AF 447 Thread No. 7

[john_tullamarine]

AF 447 Thread No. 7

Thread part -

(a) #1 starts here (http://www.pprune.org/tech-log/395105-af-447-search-resume.html#post5303737) and finishes here (http://www.pprune.org/tech-log/395105-af-447-search-resume-195.html#post6408432). Posts = 3890
(b) #2 starts here (http://www.pprune.org/tech-log/449639-af-447-search-resume-part2.html#post6408428) and finishes here (http://www.pprune.org/tech-log/449639-af-447-search-resume-part2-127.html#post6476460). Posts = 2537
(c) #3 starts here (http://www.pprune.org/tech-log/452836-af447-thread-no-3-a.html#post6476336) and finishes here (http://www.pprune.org/tech-log/452836-af447-thread-no-3-a-104.html#post6515428). Posts = 2071
(d) #4 starts here (http://www.pprune.org/tech-log/454653-af-447-thread-no-4-a.html#post6515515) and finishes here (http://www.pprune.org/6561320-post1061.html). Posts = 1061
(e) #5 starts here (http://www.pprune.org/tech-log/456874-af-447-thread-no-5-a.html#post6561270) and finishes here (http://www.pprune.org/tech-log/456874-af-447-thread-no-5-a-99.html#post6638007). Posts = 1978
(f) #6 starts here (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a.html) and finishes here (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-85.html#post6793822). Posts = 1683


Links to the various BEA reports are given below. If I have missed any of the useful papers, please PM me with the URL and I can include it.

(a) BEA site - French (http://www.bea.aero/fr/index.php), English (http://www.bea.aero/en/index.php)
- Report link page - French (http://www.bea.aero/fr/enquetes/vol.af.447/vol.af.447.php), English (http://www.bea.aero/en/enquetes/flight.af.447/flight.af.447.php)

(b) Interim Report (No, 1) Jul 2, 2009 - English (http://www.bea.aero/docspa/2009/f-cp090601e1.en/pdf/f-cp090601e1.en.pdf)

(b) Interim Report No. 2 Dec 17, 2009 - English (http://www.bea.aero/docspa/2009/f-cp090601e2.en/pdf/f-cp090601e2.en.pdf)
- Update Dec 17, 2009 - French (http://www.bea.aero/fr/enquetes/vol.af.447/point.enquete.af447.17.12.2009.pdf), English (http://www.bea.aero/fr/enquetes/vol.af.447/update.on.the.investigation.af447.17.12.2009.en.pdf)

(c) Estimating the wreckage location Jun 30, 2010 (http://www.bea.aero/en/enquetes/flight.af.447/phase3.search.zone.determination.working.group.report.pdf)

(d) Wreckage search analysis Jan 20, 2011 (http://www.bea.aero/fr/enquetes/vol.af.447/metron.search.analysis.pdf)

(e) Briefing and associated update May 27, 2011
- Briefing (http://www.bea.aero/fr/enquetes/vol.af.447/info27mai2011.fr.php) - update French (http://www.bea.aero/fr/enquetes/vol.af.447/point.enquete.af447.27mai2011.fr.pdf)
- Briefing (http://www.bea.aero/fr/enquetes/vol.af.447/info27mai2011.en.php) - update English (http://www.bea.aero/fr/enquetes/vol.af.447/point.enquete.af447.27mai2011.en.pdf)
- Briefing (http://www.bea.aero/fr/enquetes/vol.af.447/info27mai2011.de.php) - update German (http://www.bea.aero/fr/enquetes/vol.af.447/point.enquete.af447.27mai2011.de.pdf)
- Briefing (http://www.bea.aero/fr/enquetes/vol.af.447/info27mai2011.br.php) - update Portugese (http://www.bea.aero/fr/enquetes/vol.af.447/point.enquete.af447.27mai2011.br.pdf)

(f) Interim Report No. 3 July 2011 - French (http://www.bea.aero/docspa/2009/f-cp090601e3/pdf/f-cp090601e3.pdf), English (http://www.bea.aero/docspa/2009/f-cp090601e3.en/pdf/f-cp090601e3.en.pdf)

Miscellaneous pertinent links -

(a) Airbus Operations Golden Rules (http://www.airbus.com/fileadmin/media_gallery/files/safety_library_items/AirbusSafetyLib_-FLT_OPS-SOP-SEQ03.pdf)
(b) ALPA FBW Primer (http://cf.alpa.org/internet/alp/2000/febfbw.htm)
(c) C* and Civil Transports - Cranfield (https://dspace.lib.cranfield.ac.uk/bitstream/1826/186/2/coareport9303.pdf)
(d) Longitudinal Flight Control Design - RAeS (http://www.raes.org.uk/pdfs/2989.pdf)
(e) Longitudinal Stability: Effect of High Altitude and CG - Boeing (http://boeing.com/commercial/aeromagazine/aero_02/textonly/fo01txt.html)
(f) pitot static system performance - USN (Pax River) FTM (http://www.aviation.org.uk/docs/flighttest.navair.navy.milunrestricted-FTM108/c2.pdf)
(g) The Problem of Automation: Inappropriate Feedback and Interaction, Not Over-Automation. Donald A. Norman UCSD (http://www.jnd.org/dn.mss/Norman-overautomation.pdf)
(h) Upset Recovery - 16MB zip file (http://www.mediafire.com/?jrkvp2ysl7aea25)
(i) Ironies of Automation. Lisanne Bainbridge UCL (http://www.bainbrdg.demon.co.uk/Papers/Ironies.html)
(j) Cognitive Capability of Humans. Christopher Wickens Uni Illinois (http://www.humanfactors.uiuc.edu/Reports&PapersPDFs/chapters/Wickens_Durso%20Aviation.PDF)
(k) Trust in Automation: Designing for Appropriate Reliance John D. Lee, Katrina A. See; Human Factors, Vol. 46, 2004 (http://www.questia.com/googleScholar.qst;jsessionid=LHmZGvvpc1T1RT2pThDgGpvfwpMvh6f TTBPVC4hD8Tpg8J4LdQZy!-290722064?docId=5008765429)
(l) Training for New Technology. John Bent - Cathay Neil Krey's CRM site (http://www.crm-devel.org/resources/paper/bent.htm)


Search hint: You can search PPRuNe threads with a filter in Google by using the following search string example -

ths af447 site:http://www.pprune.org/tech-log/ (http://www.pprune.org/tech-log/)

This will search for mentions of THS in the AF447 threads of tech log only.

Just change the THS in the string to whatever you want to look for. This allows one to search for any term or phrase of interest throughout the threads.

Adding the site:URL end part is the magic that restricts Google to only searching in Tech Log.

This filter technique is absolutely wonderful and can be used generically to find things of interest in PPRuNe - appears to work OK in the PPRuNe search function as well.

In respect of Google searching, JenCluse has added some suggestions -

a) indenting the text block with a (one) Tab, *and*

b) emphasizing the fact that it is a search text block with some manner of . . .
<SearchText>, or
"SearchText", or
?SearchText?, etc

[AlphaZuluRomeo]

DozyWannabe, thanks for your last post (#1681) in the previous topic.

One question about it: you didn't mention thrust settings during your tests.
What were they? Did you change them during the simulated flights?

[JenCluse]

Mr Tullamarine:

May I suggest thet your suggestion ref searching, with it's example text, be modified slightly?

I's suggest that the generic entry "ths af447 site:http://www.pprune.org/tech-log/" be modified slightly, by:

a) indenting that text block with a (one) Tab, *and*

b) emphasizing the fact that it is a search text block with some manner of . . .
<SearchText>, or
"SearchText", or
?SearchText?, etc

I'm sure you get the picture :-?

[DozyWannabe]

Thanks for the thanks folks. For convenience, I'll link to my original "weekend sim research" post here:

http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-85.html#post6793521

@xcitation - Having conferred, we loaded extra fuel so that the FMGC showed MAX ALT FL379. C of G was 32% MAC. The ROD in our experiments maxed at approx 6,000ft per minute, with the VSI needle turning amber in the PFD. One of the reasons I hope someone will perform a later experiment will be to see how leaving the recovery till later in the sequence will affect the ROD, and hopefully also find out how a 40% MAC CoG will affect things. The caveat here is that the later you leave it, the further outside the tested flight envelope you go, and the more divergent the sim's performance from the real thing will become.

@AZR - Initially, autothrust dropped to Thrust Lock. We pulled the thrust levers back to match the thrust, but as we moved them the thrust increased slightly. The TRE then deliberately staggered the TLs slightly to induce a roll to the right which we trimmed out with rudder and the slightest touch of aileron.

After the initial NU pitch increase (induced with approximately half back-stick, as in the DFDR traces), we triggered a very short "G" induced stall warning as we climbed, then when the real warning sounded continuously (as happened in the AF447 scenario) we applied TOGA and held 10 to 15 degs pitch on the sidestick - during which full deflection was required in order to come close to maintaining it - as I said, the nose wanted to come down naturally if I released pressure for even a split-second.

Hope this helps!

Further details I've just been reminded of - the stall stabilised at approx 180kts IAS on the sim control with the nose-up trim at 3 degrees (the A320 hard limit). With full nose-up trim the stall was similar, but stabilised at approx. 160kts IAS. The Stall Warning was not only clear, but so loud that the TRE had to cancel it with the Emergency Cancel button in order for us to hear each other. On the second (full nose-up trim) experiment, all I had to do was briefly glance down to my left to see the trim roll forward - smoothly and *very* quickly - following recovery via sidestick pitch down.

[AlphaZuluRomeo]

DW: Thanks :)
(...)we applied TOGA and held 10 to 15 degs pitch on the sidestick - during which full deflection was required in order to come close to maintaining it - as I said, the nose wanted to come down naturally if I released pressure for even a split-second.

Hope this helps!
OK, I understand you never did (or had to) go idle to get the nose down. That's reassuring.
Now, does that apply :
- on an A330 sim
- on a real A320
- on a real A330

?

[DozyWannabe]

No problem. As for your question, I suspect there will only be minor differences - but the short answer from my end is - that's for other people to find out. :)

[fantom]

Don't under-estimate the sim.

My boss, the famous RD, said to me: "you can learn a lot about the aircraft in the sim".

True, I'm telling you.

[OK465]

Possibly if a poster might provide pictures of an A320 and an A330, we could verify by looking at them that they have similar stall characteristics.

[DozyWannabe]

The purpose of the experiments was not to provide any definitive data on stall characteristics, they were simply a technical exercise to determine if there were any obvious system problems or design deficiencies that would make recovery difficult, which it would appear there are not. We can say that with a significant degree of confidence for the A320 and a reasonable degree of confidence for the A330, as the systems designs for both share common parentage in terms of flight control requirements.

Aerodynamics is not my specialty and I'll defer to those who know better, but if I were to make an educated guess, given that a lot of the same people were involved in the airframe developement of the A320 and her larger sisters, I'd say it's a reasonable assumption to make that they are fairly docile in stall characteristics across the range. The TRE's opinion was that the A320 seems extremely docile in the stall if the sim behaviour was anything to go by - and this guy seemed to know what he was talking about - appearing to be a pilot's pilot of the old school through and through, with types from every pretty much every major manufacturer of the last 40 years under his belt.

[Machinbird]

Dozy,
Good on you for an interesting experiment.:ok:

I gather you didn't get to a high enough AOA to experience the invalid airspeed condition (or that the sim was not programed to duplicate that feature). One wonders how the little 'Bus would handle that.

[DozyWannabe]

I gather you didn't get to a high enough AOA to experience the invalid airspeed condition (or that the sim was not programed to duplicate that feature). One wonders how the little 'Bus would handle that.

The sim is not programmed to handle that (as I understand it's it's a little-understood phenomenon to start with), and even if it did we didn't have enough time to take it that far outside the envelope while I was there. My testing colleague ran them to a greater degree the week before and said that the sim outputs relayed valid speeds (despite the failed air data situation relayed to the PFDs and flight control logic) all the way down, or at least as far down as they went. Just to be clear, this test was simply intended to demonstrate that nothing was untoward with the systems, there was no unintended knock-on effect from Alternate Law affecting the controls and that even with full nose-up trim wound in it should be possible to effect a recovery with sidestick input alone *as long as the situation is recognised in a timely manner*.

[jcjeant]

One more test which confirms once more that aircraft or its systems are not to blame (if we forget that there still had the problem for a short blockage of pitot tubes) in the minutes that followed the withdrawal of the auto pilot and power levers
The plane is once again not to blame .. it's work perfect
Everything converges again to the way pilots reacted to the event
If they react well .. results will be likely those of the tests
We know that was not the case
So .. stay on the playing field:
Pilots
Air France
Regulation offices (DGAC .. BEA ... etc..)

[chrisN]

DW, does the sim produce a lot of noise when “stalled” and held in the stall with high RoD?

(It was reported in an earlier thread that somebody who had heard the CVR said that the air rush noise in the AF447 cockpit was very loud, and may have added to the PF confusion by reinforcing any belief he might have had that their problem was overspeed, as that too would have been noisy; and the pilots had probably never heard either noise before in the aircraft, and may not have heard both in the sims.)

[DozyWannabe]

Not particularly, there was a noticeable increase in volume and we were getting bumped about a fair bit - but I can tell you that in that simulator the stall warning was LOUD when it activated, certainly loud enough to get my attention even with the headset off. The only way to compare relative volume would be on the CAM track of the CVR. Hopefully the CAM and HOT sources will be made clear in the transcription of the final report.

[CONF iture]

Vertical Speed = 10,000 fpm, How can one not realise one is stalled?
It is more complex than that.
With full back stick, the PF managed to silent the STALL warning and to temporarily obtain a V/S between zero and -2500ft/min (it is not clear which V/S is recorded ...)
Of course both PNFs have no idea what are the inputs of the PF for that time.

[CONF iture]

CONF - the final report on this accident is still some time from completion, give them a chance. Having said that, given the number of ambulance-chasing vultures that would attempt to twist the data to suit their commercial ends, I'm not surprised that the release of data is limited.
Vultures won't fly much on twisted data.
Find something else.

[grity]

DW in the sim:
-I'd suspected it would involve considerable effort to hold the sidestick there for a significant amount of time, but I was genuinely surprised at just how much.

-The Stall Warning was not only clear, but so loud that the TRE had to cancel it with the Emergency Cancel button in order for us to hear each other.never say never,

your first comment show that with a bit adrenalin in your hand the spring in the SS is not so strong as expected from the designers, and this can play surely a role for the beginn of AF447s zoom climb

the second one..... if this cancel button would exist also in a real A330, I´d say they would have pressed it for the same reason.......

[Zorin_75]

your first comment show that with a bit adrenalin in your hand the spring in the SS is not so strong as expected from the designers, and this can play surely a role for the beginn of AF447s zoom climb :confused: Dozy's saying that it was even stronger than he'd expected... the second one..... if this cancel button would exist also in a real A330, I´d say they would have pressed it for the same reason....... It does. And it would be clearly evident on the CVR, wouldn't it?

[DozyWannabe]

grity:

Zorin_75 is right - it was *more* difficult (schwierig oder schwer - nicht leichter) than I expected to hold the sidestick all the way back. And the EMER CANC button is on the A330, in the same place on the ECAM panel - I've highlighted it here in yellow for you.

http://i1088.photobucket.com/albums/i331/turricaned/ecam_panel_A330.png

[grity]

well, I have to ask for pardon, for my mistranslation :ouch:

[gleaf]

The term 'detent' with SS controls keeps garabbing my attention.

So please excuse my ignorace of how the Buss's SS are rigged.
Reference point is the fly by wire stick on A-7 Corsair II aircraft.

The stick was mounted on a set of force bars with transducers.
Electronics package was set to ingnor stick forces under 4 pounds.

There was very little if any actual travel as I recall.

[DozyWannabe]

well, I have to ask for pardon, for my mistranslation :ouch:

That's OK - English isn't your first language. I made some quite embarrassing mistakes translating the initial French CVR transcript from Interim Report #3, so I can't be too hard on you.

It is more complex than that.
With full back stick, the PF managed to silent the STALL warning and to temporarily obtain a V/S between zero and -2500ft/min (it is not clear which V/S is recorded ...)

But he did have consistent stall warning for almost a minute, and a reliable V/S for just over a minute (if my reading of the traces is correct). The altimeter continued to unwind with the standby clearly visible from the right-hand seat, providing a secondary method of checking the aircraft's vertical trajectory.

Please don't think I'm criticising the PF, by the way - I'm just saying that those indications were there if he'd known where to look.

Of course both PNFs have no idea what are the inputs of the PF for that time.

Sometimes the simplest solutions can be obscured in a crisis situation - all they had to do was ask. The question is, why did they not think to do so?

@gleaf - The detents refer to the thrust lever settings, not the sidestick. The Airbus sidestick allows for a greater degree of travel than those generally fitted in fighters, however those comparing them to a computer joystick would really have to get their hands on one to understand that while the comparison works from a distance, they are obviously much stronger - chunkier and stiffly-sprung than that. They have to be to stand decades of constant operation.

[Lyman]

IMO, the most important parts of the accident are being ignored, some through ignorance, and some through active effort.

My drum? Again, the intitial 10 seconds (manual), and the ten before.

The crew inherited a maneuvering aircraft, for one or the other of two basic reasons. The AirSpeed was unreliable, or the a/c autopilot was unable to keep up with turbulence. Either way, the a/c was therefore in or on the verge of Upset.

All the interesting blather about an aircraft's performance after the fact is not relevant, it is after the fact. Post Facto.

Actively unaddressed? A rerun WITHOUT TURBULENCE factored in? A lack of notation from BEA re: the "Zipper"?

The further the pendulum swings, the more blatant is this "unknown" zone.

The entire basis for the "conclusions?" Unrelated to the onset of Upset, imho.

Commanded or no, the climb qualifies as Upset. What initiated the Climb?

Crew, in response to instruments.

Ambulance Chasers? Fanatical Toadies? Nil/Nil. fmm.

[gums]

Salute gleaf!

You can find a good link and description of the 'bus sidestick by searching one of our earlier threads.

With no small amount of time in the SLUF, I can attest to the use of force transducers for the stick grip. Seems like breakout force was very low and the 4 pounds reference might have been when the physical stick began to move. For FCF's we would brace the stick with our knees and one hand, then exert force on the grip. With CONTROL AUG enabled, the control surfaces would move. Sure made formation flying a lot more precise.

That stick grip was used on the original Viper and worked the same way - no physical movement. Later jets, like from number 30 or so, had 1/8 inch of movement.

@DOZE

I take it that the increasing force per degrees of stick deflection was impressive?

back to our regularly scheduled discussion...

[DozyWannabe]

For the record, the turbulence encountered by AF447 was described as "MODERATE", which has a very specific meaning - namely :

MODERATE - Changes in altitude and/or attitude occur but the aircraft remains in positive control at all times. It usually causes variations in indicated airspeed. Occupants feel definite strains against seat belts or shoulder straps. Unsecured objects are dislodged. Food service and walking are difficult.

I'm sure that given the thousands of FBW Airbuses criss-crossing the globe on a daily basis for 23 years, most of them must have encountered "MODERATE" turbulence at one time or another. As yet there have been no reported incidents of such turbulence inducing an autopilot disconnect, but there have been several cases of disconnect relating to unreliable airspeed. Therefore it's quite reasonable to state that the most likely cause of disconnect was unreliable airspeed, and given the ACARS log and the DFDR records it becomes practically certain that unreliable airspeed was the reason.

As for ambulance-chasers, an example was the Aeroperu 757 crash, in which the initiating event was the inappropriate use by airport ground staff of silver duct tape to cover the static ports. The lawyers still elected to go after Boeing (who, true to the edicts of ambulance-chasing, had by far the deepest pockets), despite the manufacturer having done nothing materially wrong.

@gums - Yes, the build quality of the sim was very impressive in general. There's a reason why the top-drawer *home* sim component sidestick costs approximately $3,500 (thus the real deal I experienced likely costs more) and home computer controllers cost 1/100th of that. :)

[Organfreak]

Good Morning, Ppruners,

I have eaten all of my prunes this morning, and feel quite regular!
Has anyone found a source for the Otelli book, in English, for sale in the U.S.?

I personally feel that Otelli is out-of-line in drawing any conclusions at all at this juncture, and he comes off as an ambulance-chaser, but that doesn't mean I wouldn't be interested in reading the book.

All I can find is the French version, for $50!

Thanks for any feedback.

[GarageYears]

DW, does the sim produce a lot of noise when “stalled” and held in the stall with high RoD?

(It was reported in an earlier thread that somebody who had heard the CVR said that the air rush noise in the AF447 cockpit was very loud, and may have added to the PF confusion by reinforcing any belief he might have had that their problem was overspeed, as that too would have been noisy; and the pilots had probably never heard either noise before in the aircraft, and may not have heard both in the sims.)

As noted previously, I am one of "those" engineers responsible for developing the sound models used to generate the sounds in simulators (many, many types now). There would be no vertical speed component contributing to the noise signature in the sim, unless the company producing that sim extrapolated way outside of the available sound data supplied with the aircraft data package. The key driver for aeronoise is CAS modulated by Mach factor.

[jcjeant]

Sometimes the simplest solutions can be obscured in a crisis situation - all they had to do was ask. The question is, why did they not think to do so?James R.Chiles
The most dangerous time is when the operators don’t know what they don’t know

[Dani]

Interesting discussion. Congratulations to Dozy for his field research. I do not doubt any second that what he experienced was very close to what did the crew of AF447.

Still this is no proof that he (and me, and BEA and some other pro Airbus people) are right about the accident. You still could argue that the simulator did not simulate what the real aircraft experienced in her dire situation. That the simulation of the case is just an interpolation of known aircraft situations. That the AF447 was so far away from known that they experienced something completly else.

The only thing that Dozy proofed is what we (Airbus people) already knew: stick movement were consistent with aircraft movements, Airbusses are pretty easy to handle and stall recognition, recovery and UAS situation are possible to handle.

But I'm sure he is right. And that an A330 is behaving very similar if not easier than a A320.

[CONF iture]

Sometimes the simplest solutions can be obscured in a crisis situation - all they had to do was ask. The question is, why did they not think to do so?
The simplest solution has a name : Fully visible control columns - they tell without talking.

What do you wanna ask ?

What can you reply ?
"I am full left - half back - a third left - full back - neutral - a touch forward - mainly right - full forward - back left .........................."

[Old Carthusian]

It is highly unlikely that control columns would have made any difference. Go and read the accident report on the Airborne Express DC8 stall crash which involved control columns - they didn't make any difference to the outcome. Absorb that report and remember it before you post - the control column is another red herring. A proper and comprehensive instrument scan and properly executed CRM are what would have helped. The fact that (as Dozy identified) no one asked is highly significant and indicates a serious breakdown in communication at a vital time, just when communication should be clear and frequent.

[CONF iture]

The fact that (as Dozy identified) no one asked is highly significant and indicates a serious breakdown in communication at a vital time, just when communication should be clear and frequent.
The fact that a PM would need to ask the PF what are his inputs on flight control commands is highly significant how the concept of the sidesticks by Airbus is poor.

Read and absorb my previous comment (http://www.pprune.org/6783369-post1554.html) regarding the DC8 event and remember it before you post.


Sidestick is a sure way to waste valuable information in a multi crew operation.

Dozy never replied (http://www.pprune.org/6768340-post1386.html) - Where such statement is erroneous Old Carthusian ?
Please comment.

[Linktrained]

There were a few comments earlier that AF447's long stall had been very stable, with a high AoA, although with a fairly steady bank. When flying as a SLF when I have been able to see a wing tip through a rear cabin window across the aisle during Take-off, at what I would guess was Vr, the wing tip lifts aerodynamically, thus increasing the static dihedral. With the very high AoA AF447 had, might not this aeroelastic effect have tended to keep the aircraft stable, awaiting some other control input ?

The aircraft that I flew, attempted to have more rigid wings. (The biplanes even had Flying wires and Landing wires between the wing struts !) And later, I would be unable to see the wing tips on Take-off, even had it been safe to do so. With more rigid wings I would guess that we got a rougher ride in any turbulence for a given TAS.

( This "wing-tip-lift" is not unique to A or B, it is just that I have seen it there, on both, as an SLF .)

[Machinbird]

My experience at and beyond stall AOA in swept wing jets (trying to hold the nose up in a low speed scissors) was that centering the stick laterally and using gentle rudder inputs had the best effect in keeping the wings level. But even then the wings rocked a lot and it needed bigger and bigger rudder inputs to pick the low wing up.

I'm wondering if all those spoilers on the A330 wing more than counterbalance the adverse effect of the ailerons and make it practical to reverse the roll using the stick, particularly once well past the stall AOA? Or is it just the rudder effects from the BYDU and pedal inputs that rolled AF447 back the other way.

[BOAC]

I'm wondering if all those spoilers on the A330 wing more than counterbalance the adverse effect of the ailerons and make it practical to reverse the roll using the stick, particularly once well past the stall AOA? Or is it just the rudder effects from the BYDU and pedal inputs that rolled AF447 back the other way. - I'm pretty convinced you are right. The apparent 'restorative' effect of aileron on 447 in a fully stalled condition has puzzled me for a long time and goes against 'conventional wisdom'. I now believe that the commonality of large spoiler deflections with aileron means we may have to re-write the book on the effect of roll control at the stall..

[rudderrudderrat]

Hi BOAC,

I now believe that the commonality of large spoiler deflections with aileron means we may have to re-write the book on the effect of roll control at the stall..
I don't think so.

On page 96:
At 2.12.45. "The copilot sidestick is to the left in stop position. The roll angle changes from 12° right to 41° right in 3 seconds then fluctuates between about 20° and 40° right (period of 10 seconds)
"Hey you’re in … get the wings horizontal Get the wings horizontal"
"That’s what I’m trying to do"
"Get the wings horizontal"
At 2.12.59:
"I’m at the limit … with the roll"
"The rudder bar"

It strikes me that the roll control worked the wrong way during the stall (which agrees with current wisdom). The Captain ordered the use of the rudder bar, which then picked up the wing.

I agree with Linktrained and think it was simply the massive side slip which they had with 40 degs of bank (due no radius of turn) and the dihedral effect which caused it to stabilise.

[BOAC]

Quite possible.

Can someone remind me please? We know that fore and aft SS demands are 'processed' by HAL according to some 'law', be it 'g'/attitude or whatever . What does HAL think a pilot wants when the SS moves over in whichever *** 'law' the beast was in at the time? Roll Rate/bank angle/acceleration in roll?? IE When PF moved the stick to the left, what did HAL think he wanted - and gave him?

[Zorin_75]

Roll control is direct law, stick position -> surface position.

[gums]

Salute!

Beg pardon, but roll commands do not command a 1 for 1 deflection of either the spoilers or ailerons in Alt1 or Alt 2, only in "direct law". That's what my copy of the FCOM shows.

The commands except in "direct" are roll rates, and the "gains" are set by various inputs and other control surface settings. So no direct deflection of surfaces according SS deflection.

This is a fairly standard implementation for FBW jets. The rudder will move to help rolling and minimize adverse yaw. In the Viper, HAL would command the rudder to very large deflections when rolling at max rates and slow speed.

At high AoA's, I go with 'bird. Use rudder and not aileron for roll. Spoilers can reduce adverse yaw and such, but my understanding is that the outboard spoilers on the 'bus are inhibited once gear up. So the inboard spoliers may not have helped as much as rudder.

The CVR shows the PNF mentioning the "rudder bar" when PF had full SS deflection for roll and the jet was not responding. Here again, knowing you were stalled or approaching a stall might have changed the PF stick inputs. However, in view of most PF stick inputs and PF's possible lack of experience flying at extreme AoA , then I can see a bit of the rationale for roll inputs, but not pitch.

Sent by an old FBW pioneer.

[BOAC]

OK - seconds out - round 2

Zorin Roll control is direct law, stick position -> surface position.

Gums roll commands do not command a 1 for 1 deflection of either the spoilers or ailerons in Alt1 or Alt 2, only in "direct law". That's what my copy of the FCOM shows. The commands except in "direct" are roll rates, and the "gains" are set by various inputs and other control surface settings. So no direct deflection of surfaces according SS deflection.

Which FCOM/understanding is correct? It could be important in a confused cockpit. Not a lot of time to open an FCOM volume? Let's get it right?

Ding Ding Ding.

Oh yes- a round is 3 minutes I think - about the time from 38,000 to sea level at a high rate of descent .

[rudderrudderrat]

Interesting. My A320 FCOM says:

"LATERAL CONTROL
When the aircraft flying in pitch alternate law, lateral control follows the roll direct law associated with yaw alternate or mechanical.

ROLL DIRECT LAW
Refer to Direct Law."

The fact that rudder produces a roll (despite the side stick is not centred) suggests to me that it is not commanding a roll rate in ALT Law.

[RetiredF4]

It is quite simple, and said before.

In high AOA and especially in the stall region the aileron is the wrong control surface for roll control.

If you like, use any aircraft model to get a picture from following description.

In normal LAW by a roll action on the side stick, the pilot commands a roll rate, with minimized sideslip (automatic turn coordination), elaborated in the FCPC.

In Alternate 2 LAW the roll control is direct, an order on the side stick directly commands a deflection, according to a kinematic. The yaw control is achieved from the pedals, through a mechanical linkage without automatic sisdeslip correction. A Dutch roll damping function using limited yaw rate data is introduced via the yaw damper servoactuators.

When PF wanted to raise the right low wing with a left SS input, the downgoing aileron on the right wing produced a lot of drag, thus inducing a yawing momentum to the right (into the low wing).

Normally the upgoing spoiler on the left wing would not only help in roll, but would produce drag as well and thus reduce the yawing moment, but under such high AOA the spoiler is blanked out, does not assist in roll and produces not enough drag to prevent the yaw. Sideslip protection was not available, and manual rudder not used.

The induced yaw into the right (low) wing increased the sweep back in relation to the relative wind and thus decreased the available lift on this wing, where on the opposite wing the sweep in relation to the relative wind decreased, thus increasing the lift.

Why did the bank not incrase beyond the 40° (like going into a spiral dive) but oscilated between some left bank and lot of right bank? I don´t know for sure, but it might have something to do with the dutch roll dampening function:

In the event of loss of the inertial data from the ADIRUs, the yaw rate data for Dutch roll damping are provided to the FCPCs via a unit comprising 2 rate gyros. In case of 3 FCPCs loss, the Dutch roll damping is achieved by the FCSCs with yaw rate data coming from the rate gyro unit

Thus left SS input without rudder input produced exactly the opposite what the PF intended to achieve.

One more comment concerning the stall behaviour. It looks like most pilots expect violent maneuvers of the aircraft in a stalled situation, heavy g variations, fast nose position transitions like bank pitch and yaw changes or what so ever. I expierienced the stall violent at the point of departure, but after those initial unpredictable movements nearly stable, but just not logic responsive to the flight controls. AF447 departed and behaved similar, and in combination with a different expectation might also have led the crew to take a stalled situation not into consideration.

[gums]

You have it nailed, BOAC.

I have a hard time blaming the crew for 100% of the problem when I see the current training regimen and emphasis upon HAL to "protect" you and the 200 SLF's you are responsible for getting home.

The reversion sequence of the 'bus and its loss of "protections" all along the way disturbs me to this day. Seems the crews are thinking "Normal", and have been "trained" thru hundreds of hours in "Normal" law and "normal" flight conditions. Then when things go Tango Uniform, we see confusion and poor cockpit resource management and..... Also remember that some of us here didn't have the CRM problem, nor could we take a nap someplace aft and hit the bathroom or...

I also have a problem with the warnings and chimes and criteria for them in the 'bus. Many of the flight control functions revert to back-up modes according to loss of speed or whatever. Where should the pilot hang his hat? What's working? And let's forget all the "protections", shall we. I do not advocate a reversion to "direct" law unless there are multiple catastrophic failures of sensors or mechanical systems. It would seem to this old, dumb pilot that we use whatever the jet and/or HAL can give us with clearly defined limits that can be understood by the pilots. For example, who gives a rat's about bank angle limits once outta "Normal" law? Why have two max roll rate limits once reverting from "Normal" to ALT1 and then ALT2 and then "unusual attitude" and then..... Get my point?

Guess/hope the whole affair will result in better crew training, but I would still like to see at least a few concessions by the 'bus folks concerning the reversion sequences, warnings, etc.

[CONF iture]

I do not advocate a reversion to "direct" law unless there are multiple catastrophic failures of sensors or mechanical systems.
gums,
Beware that Direct Law on the bus is nothing worse than any conventional aircraft.
It has also the huge advantage to prevent the risk of any protection to kick in on false information.
It puts back the trim duty on pilot's shoulders and would have prevented AF447 to autotrim full up under STALL warning.

[gums]

A great point, CONF.

With the FBW systems, there are usually "gains" that depend upon dynamic pressure, and I would prefer as a pilot to still have something I could count on. So in the dinosaur FBW I flew we had "standby gains" when the air data went south. Two values - one gear down, one gear up. Sure, if we flying at the speed of stink, the jet was sensitive. Gear down was about the same as normal.

I have yet to see the charts of the 'bus stick commands versus gee or roll rate.

For example, here's mine for roll command:

http://i120.photobucket.com/albums/o196/gatlingums/roll_cmd.jpg

Now this is just the "command", and the actual control surface deflection could be 2 deg or 25 deg. So non-FBW folks may not completely understand the implementation.

As I understand it, the 'bus "direct" law is just the same as most all planes with 100% hydraulic control wheels/sticks and zero force feedback from the control surfaces. BFD, Been that way for most jets since the 1960's.

I would still like to see some of the control laws on a "block diagram" and I'll try to have one of mine scanned so all can see the inputs to each surface and the commanded movements using the stick.

[Old Carthusian]

No Conf iture
The fact that the PNF would ask a question shows that he was paying attention. I take it you have gotten your instrument rating? If so, you will recall that you are trained to trust your instruments not your unreliable estimate of what a slanted piece of metal may be doing or your sense of 'feel'. How someone perceives the same event can vary enormously especially under stressful conditions. Rely on the instrumentation (altimeter and artificial horizon) not on your eyes.
The yoke would not have made a blind bit of difference in this case. One can be sure that the PNF would have done nothing except summon the captain. If you take a look at the various reports you can see he perceived a problem but did nothing. Why would the yoke have made any difference to this lack of action? Remember he could see what was happening from his instruments. Do not get led astray by red herrings about yokes or otherwise. Your comments on the sidestick introduce a side issue which is totally irrelevant. The number of Airbuses fitted with sidesticks flying safely demonstrates this.

[Zorin_75]

Oh my.
ALTERNATE LAW
(...)
Handling Characteristics (...)
In Roll, depending on the failure level, control is either normal (ALTN 1) or direct (ALTN 2). In roll direct, the aircraft appears to be very sensitive and bank stability is no longer active.

DIRECT LAW
(...)
Handling Characteristics
The handling characteristics are similar to a conventional aircraft. (...) In roll, aileron and spoiler deflection is proportional to sidestick deflection. Direct law works with the yaw damper to provide a minimal turn coordination.
I can't believe we're debating again what flight law they were in. :ugh:

[DozyWannabe]

@CONF - "Dozy didn't answer" because he was out at work, so he can continue to pay for the privilege of joining in these delightful discussions. There have been too many LOC accidents in yoke-equipped airliners for the argument that it would have made a difference to stick, and we've already been round that hamster wheel more than once.

@gums - Your aerodynamic knowledge is beyond question, but both Alternate 1 & 2 are "roll direct" [Correction - Alt 2 is roll direct, yay early morning!]. The crews may be "trained in Normal", but in the sim there wasn't that much difference between Normal and Alternate roll handling. It was more sensitive outside the stall, but it took me all of a few seconds to get used to. Also, it looks like the trim is a red herring and the aircraft can be recovered in approximately 5,000ft on sidestick alone *even with full nose-up trim wound in*.

However - in the sim, the TRE noticed that I was trying aileron in the stall sequence and told me to use rudder instead. On this occasion he was standing over the pedestal having just wound the trim on and he could obviously see what I was doing in order to tell me not to do it.

This discussion isn't going anywhere until people start listening to each other and not just making assumptions based on their own prejudice against a specific design. I've never ignored anyone on this forum in my life until Lyman, and if I keep hearing "HAL" used to describe the Airbus system, those that use it are likely to join him.

[airtren]

No Conf iture
The fact that the PNF would ask a question shows that he was paying attention. I take it you have gotten your instrument rating? If so, you will recall that you are trained to trust your instruments not your unreliable estimate of what a slanted piece of metal may be doing or your sense of 'feel'. How someone perceives the same event can vary enormously especially under stressful conditions. Rely on the instrumentation (altimeter and artificial horizon) not on your eyes.

The visual contact with the PF's SS, the seeing of where the SS is at any given point of time, would have given to both PNF and Captain, the immediate, DIRECT, unaltered information of what the PF is doing.

Inferring the positions of the SS from instruments or anything else is INDIRECT information. When the instruments are not reliable it can be lethal.


The yoke would not have made a blind bit of difference in this case.
Of course it would, and not because it's a yoke. Ultimately, it's not about the "yoke" versus "SS", it's about the "SS" problem, which is its positioning in the A330, that can impact an exact, immediate, and precise visual perception of the actions on it.

As I've mentioned it in the past, and will do it again, that using INDIRECT versus DIRECT information, is an elementary system design issue that is known to create problems, where ever is present in any application where immediate and accurate perception of information is critical, one of which happens to be a passenger A/C cockpit.

@CONF - "Dozy didn't answer" because he was out at work, so he can continue to pay for the privilege of joining in these delightful discussions.
You're doing very well with your presence on this Forum. Ironically, the quality of the service brought to Airbus does not depend on how blindly one sticks to his mission.

[DozyWannabe]

@airtren

You and Lyman are sounding even more like you're one and the same - so what am I, a "servant of Airbus" or a "fanatical toady"? For the record I neither work for Airbus nor any of their clients or suppliers. I think modern aviation on a technical level is nothing short of a bloody marvel whether the aircraft come from either side of the Atlantic.

I prefer to think of myself as a neutral party with an inbuilt dislike of bullsh*t and preference for evidence and experimentation over hearsay. I was privileged enough to take part in one experimental session and I'm just telling you what I learned and observed. The response from those determined to hold on to the "AIRBUS BAD" philosophy was to bring control columns up *yet again*, with no evidence that they would make a difference.

[CONF iture]

Rely on the instrumentation (altimeter and artificial horizon) not on your eyes.
So how do you do that now ... you need the Braille !?

[CONF iture]

@CONF - "Dozy didn't answer" because he was out at work, so he can continue to pay for the privilege of joining in these delightful discussions. There have been too many LOC accidents in yoke-equipped airliners for the argument that it would have made a difference to stick, and we've already been round that hamster wheel more than once.
As a politician you twist the question not to address it and then invoke 'the hamster wheel'.

[DozyWannabe]

No sir, it has already been addressed - by people far more worthy of addressing it than me - in several places on the previous threads, hence the reference to the hamster wheel.

I also found it mildly amusing that my lack of an immediate answer was used as an indication that I did not have one, especially given the fact that a few months ago I left you an open goal to shoot at on another thread to talk about your specialist subject - namely Habsheim - and yet you never replied.

In short, I can't help but suspect that the anti-Airbus brigade "ain't got nuthin'" - to coin a phrase - to go on here, and are simply resorting to calling out their stock phrases.

[Machinbird]

Also, it looks like the trim is a red herring and the aircraft can be recovered in approximately 5,000ft on sidestick alone *even with full nose-up trim wound in*.This may be a premature pronouncement. In Dozy's case, the trim came promptly back down with nose down stick. If I understand CONF's experience, it did not.

On AF447, it seems to have stayed solidly at its highest value. Was there long enough nose down to get it even moving a bit if it was working? Did the airspeed have to become valid before it would be enabled? Was some interlock stopping it?

[Zorin_75]

In Dozy's case, the trim came promptly back down with nose down stick. If I understand CONF's experience, it did not.
According to this Stalled AF447 did not switch to abnormal attitude law (http://www.flightglobal.com/news/articles/stalled-af447-did-not-switch-to-abnormal-attitude-law-357394/)
BEA says abnormal attitude law, which could have stopped autotrim, wasn't entered.
Maybe an artifact of the way the sim was forced into alternate in confiture's case ?

[OK465]

The A330 simulation referred to by that poster involved a full forward SS input but 'the nose did not come down'.

If the SS input did not change the existing dynamic, why would there be a requirement for the autotrim to change even in ALT2?

Autotrim is a 'TRIM' function for dynamic pressure changes which would alter the existing 'G'/longitudinal command and doesn't 'necessarily' follow the direction of SS movement unless the SS has some effect on the existing flight conditions.

These are two very different simulations, neither of which can positively be confirmed as representing either aircraft faithfully. Both posters may well want to monitor the SD FLT/CNTL page the next time they get a chance to do this.

The other side of the coin is that one or both of the simulations MAY actually represent the aircraft characteristics and certainly will up to the point that actual stall flight data was accumulated and incorporated in the simulator flight package. Beyond that, well there are a number of posters here that are sure they know what will occur...

[Lyman]

There is (to me) a lack of technical discussion of the TRIM operation prior to its travel to NU stop at (near) the top of climb. The accepted wisdom is at 3 degrees NU (-3), the THS stopped moving. The rest of the climb was not followed (augmented, commanded) by TRIM.

It is said that it stopped because the elevators had requisite authority to change PITCH w/o the slab. This infers a data point at which the THS inhibits, leaving to the stick, commands that do not "require" THS follow.

This implies (to me), a computer generated point at which "maneuvering" is left to elevators alone. This is inconsistent (at least to me) with AB philosophy, even in ALTLAW2.

Had the TRIM continued, would we see less mayonnaise, and more stability in the climb to 38k? Was PF "hunting"? I think he was, and though that may be improper, I certainly see how that could happen. Afterall, we know he lost SA with PITCH/POWER from the git, with his intitial input.

The THS was articulating to, (and through) handoff to manual flight, why did it stop? It moved as the PF was ordering a climb, what was different about his initial input from the regime that prompted the FC to stop the THS in the zoom? Again, his initial input caused STALLWARN, so it wasn't for lack of emphasis, or authority, that the airframe sensed the lack of a need for continued THS?

What separates PITCH command (NOT LAW), in auto from PITCH command in ALTLAW2? In the time it takes (took), to climb 3k feet, the PF became accustomed to elevators/results? I realize there is room here for slandering the crew, but it seems to me, the computer was little help in the transition.

I'm looking for an honest answer to an honest question, not flames or politics.

[airtren]

...
For the record I neither work for Airbus nor any of their clients or suppliers.
I strongly believe that sentence. If you worked for Airbus, you would have been long ago silenced, in a way or another, as I know the perception of de-service to Airbus, and dislike of your type of defense.

I prefer to think of myself as a neutral party with an inbuilt dislike of bullsh*t and preference for evidence and experimentation over hearsay. Your not recognizing the difference between DIRECT and INDIRECT information transfer combined with the advertising of a software engineering background is again, as it was in past posts of yours a clear indication of BS.

I was privileged enough to take part in one experimental session and I'm just telling you what I learned and observed. As far as I am concerned the BEA report information on the Airbus simulation of the AF 447 case is sufficient, and any simulation on a non-A330 may be a valuable personal experience, but cannot bring true scientific value - it's rather a source of more speculation, and self-serving argumentation.

You may pretend to be, or would like to think as "neutral", but it's so obvious were you stand. Your personal attacks, ....

The response from those determined to hold on to the "AIRBUS BAD" philosophy ....
In short, I can't help but suspect that the anti-Airbus brigade "ain't got nuthin'" - to coin a phrase - to go on here, and are simply resorting to calling out their stock phrases. the "anti-Airbus brigade" obsession, and your self assigned mission of defending Airbus at any cost, even those elements that are scientifically indefensible, for anyone that is a professional, and wrongly extrapolating faults with certain few Airbus elements, as being applied to the entire Airbus design, is a good indication of the type of alignment you're driven by.

[Clandestino]

Sidestick is a sure way to waste valuable information in a multi crew operation. Can anyone provide any verifiable source for this statement? If we were to believe it then right now thousands of FBW Airbi currently airborne are operating with considerable wastage of valuable information in a multi crew operation.

The yoke would not have made a blind bit of difference in this case.Probably wouldn't make a lot off difference in the accident sequence but it would make a whole lot in analysis phase: with independent sidesticks, there is no doubt who made which controls input.

[HazelNuts39]

The accepted wisdom is at 3 degrees NU (-3), the THS stopped moving.Not true, see Interim #3, page 42.

[Lyman]

Clandestino.

Additonally, with Yokes, the temptation to concurrently provide input to the controls on both sides is alleviated.

Your thoughts?

[DozyWannabe]

You may pretend to be, or would like to think as "neutral", but it's so obvious were you stand. Your personal attacks, ....

I wasn't the one who obliquely described me as a "fanatical toady" - I've said nothing personal to anyone who hadn't already got personal with me.

the "anti-Airbus brigade" obsession

It's not an obsession, it's just the way of things - whenever the subject comes up, the same 3 or 4 posters always materialise and cast the same aspersions they always do - rarely if ever bringing anything new to the discussion.

and your self assigned mission of defending Airbus at any cost, even those elements that are scientifically indefensible

I'd love to see the post where I assigned myself that mission, because it must have been someone else using my handle - unless of course you're making it up. And I'd also love to know what you find "scientifically indefensible" about the design.

I'm just here to make sure that press-induced falsehoods about the design, including but not limited to it being "designed to take pilots out of the loop", "the first step in replacing pilots", "designed by managers and computer nerds without pilot input" and "reliant on the French Government covering up the real reasons for accidents" meet with robust and evidence-supported rebuttal. Any or all of which are not only substantively untrue, but also defamatory against the hard work of all the teams that have worked on it over the years, some of whom are no longer with us.

for anyone that is a professional, and wrongly extrapolating faults with certain few Airbus elements, as being applied to the entire Airbus design, is a good indication of the type of alignment you're driven by.

In this case, aside from the pitot tube issues (which are serious, and Airbus/AF have some 'splaining to do there...), it's looking increasingly likely that there were no hardware (or indeed software) faults involved in the crash of AF447. All the talk of sidestick vs. yoke and FBW vs. conventional control are therefore nothing more than a distraction from the issues at hand. Laying the blame for insufficient training at Airbus's door because management got the wrong idea about what automation means is also a false attribution. If it was Boeing getting the stick I'd be just as annoyed about it.

It's not about the manufacturer and it's not about defending modern automated aircraft in the slightest, it's about demanding a degree of factual basis behind the discussion rather than a bunch of tired old cliches that have been doing the rounds since 1988.

[HazelNuts39]

aside from the pitot tube issues (which are serious, and Airbus/AF have some 'splaining to do there...)Dozy,
Given -


the history of the pitot issues in Interim #1,
the recommendations in the area of certification in Interim #2,
the existence of UAS procedures in AF and AB manuals,
that DFDR and CVR have hardly added anything to this issue,

do you expect anymore 'splaining in the final report, or are you perhaps referring to the judicial proceedings?

[jcjeant]

Clandestino
Can anyone provide any verifiable source for this statement? If we were to believe it then right now thousands of FBW Airbi currently airborne are operating with considerable wastage of valuable information in a multi crew operation.Well .. it's not always wastage of valuable information
We must take in account the airbus FBW laws and autopilot
We have indeed a multicrew .. in fact (normal crew manning) 3 members .. 2 humans and the additional crew member .. the AP computer-FBW system entity
In normal law ... it's no wastage (human crew members hands are out of SS)
In other laws (or when a human crew member put hand on SS) it can be a wastage of valuable information

[DozyWannabe]

Dozy,
Given -
...
do you expect anymore 'splaining in the final report, or are you perhaps referring to the judicial proceedings?

I'm sure the final report will condense what's in the interim publications, and maybe something will come out of the judicial proceedings, but primarily I was just trying to make it obvious that I believe that mistakes were made, although it probably followed the letter of the law at the time, and this is all with the benefit of 20/20 hindsight.

In short, I'm not trying to "defend" or "protect" Airbus indiscriminately, I am and always have been simply trying to keep the discussion to the matters at hand and not get sidetracked by the same old kvetching.

[Old Carthusian]

The Red Herrings become a shoal. Direct v Indirect input now. Instruments, AirTren, instruments are the key. They are not fooled by panic, tension, stress or any of the other factors which so much mess up human perception. They can be relied on to give an accurate reading of a situation provided you remember your training and cockpit drills. No need to look at the yoke or whatever, look at your instruments. One can be sure that BEA know who was making the inputs - a yoke is not needed for that. As for the flight crew they also knew so where does the yoke help? A yoke is a piece of equipment to transmit inputs to the aircraft it is not a magical cure all to save lives. It performs its function like sidesticks do and some pilots prefer it. This is human nature not everyone likes the same thing. But it is not superior in any way to a sidestick.
Conf iture - what on earth are you talking about?

[CONF iture]

No sir, it has already been addressed - by people far more worthy of addressing it than me - in several places on the previous threads, hence the reference to the hamster wheel.
Do not hide Dozy.
No reply in sight ... but put your own thoughts using your own words.

Habsheim (http://www.pprune.org/6661648-post473.html) ?
AF447 has its own thread.
Habsheim should also ...

Can anyone provide any verifiable source for this statement? If we were to believe it then right now thousands of FBW Airbi currently airborne are operating with considerable wastage of valuable information in a multi crew operation.
Correct.
Usually more relevant in take off and landing phases but AF447 demonstrates how it can also be true at FL350.

If the SS input did not change the existing dynamic, why would there be a requirement for the autotrim to change even in ALT2?
Because the sidestick provides control of elevators and THS to achieve a load factor proportional to stick deflection.

Both posters may well want to monitor the SD FLT/CNTL page the next time they get a chance to do this.
Something to do for sure ... what would be your assumption or presumption for the elevators position with stick full fwd ?

[CONF iture]

One can be sure that BEA know who was making the inputs - a yoke is not needed for that. As for the flight crew they also knew so where does the yoke help?
2 PNF knew the PF was making inputs - Did they know which inputs he was making ?

[Old Carthusian]

Yes by looking at the instruments. An input produces a certain pattern on your instruments and you can understand what your aircraft is doing. The seated PNF could see the zoom climb from his instruments. He even mentioned this. The captain also could see the instruments when he entered the cockpit.

[RetiredF4]

Confiture
2 PNF knew the PF was making inputs - Did they know which inputs he was making ?

Answer Old Carthusian
Yes by looking at the instruments. An input produces a certain pattern on your instruments and you can understand what your aircraft is doing.

Would you explain yourself in relation to the timeframe starting from 02:12:45 (http://www.pprune.org/6798699-post36.html)?

Stick was full left, aircraft was banked to the right, how do you know by instruments, what kind of inputs are made by the guy in the dark 1 meter away?

[CONF iture]

... or 02:11:55 when the pitch is 10 deg below horizon ... where is the stick Old Carthusian ... !?

[gums]

Once again, I have to go with Retired.

If I am not the pilot in control, then simply looking at the instruments does not provide the best feedback required to maintain control or get the beast going where you wish. It is true that having a mechanically coupled wheel/stick would help the "other guy" understand what was happening, but the jet involved did not have that feature. Retired pointed out that the "other guy" did not know exactly what the control inputs were and finally advised to use some rudder to pick up the low wing.

I realize that I do not have 20,000 hours as some here. But I prolly had as many takeoffs and landings with my measly 4,000 hours, none of which had a co-pilot to help/monitor. I also had to solo pilots from a "chase" aircraft on their first hop, as we had no family models. So not feeling their control inputs was very familiar to me. 'nuff of that.

Rely on the instruments? Hell, the tragedy started when the instruments became unreliable!! BEAM ME UP! So would you trust the speed and air data after the A/P disconnected and then the PF states we're in alternate law? Then we have stall warnings and other chimes.

Those that have not flown FBW still need to realize that even in the Airbus "direct" law, the computers still modify the control surface deflections and deflection rates. To wit from FCOM manual I have:

- "In all configurations elevator deflection varies as a function of aircraft C.G."

- Roll rate commands are limited in ALT 2 depending upon gains and configuration". 20 - 25 deg/sec compared to 15 deg/sec in "normal". So roll is not a direct movement of the ailerons/spoilers WRT to stick inputs.

Finally, this old curmudgeon is not anti-Airbus. I crowed about the A320 with partners of mine on our first flight in one of them. Asked them to look at the ailerons and spoilers moving to keep bank angle constant even in mild turbulence. Small movements not possible with the older systems. I gained a lot of respect for the GD folks that did the Viper system after a few minutes flying the beast. I gained more after my leading edge flap failure ( see my bio on my profile).

I simply feel that there are too many protections that are different between all the reversion laws. For example, why the change in roll rates? Why keep changing things when air data is deemed unreliable by HAL ( had to get that in for Doze, heh heh) versus switching to a simple standby gains vale or all the gains and such? And the beat goes on...

And then there's the issue, a big one, of crew training for worst case scenarios, and that may be a major recommendation of the accident board, IMHO.

Gotta go, and I only have a basic B.S. in the academic arena, but prolly a PhD in the real world school.

[DozyWannabe]

@Franzl, CONF:

The precise position of the stick is considerably less important than being able to work out that the stick is not where it should be. Once that is ascertained, then the only logical recourse is "I have control".

This isn't a trainer, where the junior pilot follows through his senior's movements - this is line flying, and if your colleague is not successfully controlling the aircraft into a recovery, then they have no business continuing to do so.

Also, CONF - if you use the Search function - my username plus the keyword "yoke", you have instant access to everything I've ever said on the matter, including conversations with you. I'm not going to be your monkey by rehashing it again.

[Machinbird]

O.C.
The Red Herrings become a shoal. Direct v Indirect input now. Instruments, AirTren, instruments are the key. They are not fooled by panic, tension, stress or any of the other factors which so much mess up human perception. They can be relied on to give an accurate reading of a situation provided you remember your training and cockpit drills. No need to look at the yoke or whatever, look at your instruments. One can be sure that BEA know who was making the inputs - a yoke is not needed for that. As for the flight crew they also knew so where does the yoke help? A yoke is a piece of equipment to transmit inputs to the aircraft it is not a magical cure all to save lives. It performs its function like sidesticks do and some pilots prefer it. This is human nature not everyone likes the same thing. But it is not superior in any way to a sidestick.Only partially correct I think. Up until the stall, the instruments did tell the story of what the inputs were.

After the stall, the aircraft began to act perversely in roll and pitch, and at that point, the control inputs were masked by the aircraft's gyrations.

This must have been immensely confusing to both the PF and PNF.:ooh:

[CONF iture]

Also, CONF - if you use the Search function - my username plus the keyword "yoke", you have instant access to everything I've ever said on the matter, including conversations with you. I'm not going to be your monkey by rehashing it again.
So consider me as being yours as such search has been done for awhile now ... but nowhere could be spot a comment how my statement "Sidestick is a sure way to waste valuable information in a multi crew operation" could be erroneous.

[Old Carthusian]

Retired F4
Both the PF and PNF have displays with the same instrumentation on them. Your artificial horizon will tell you if the plane is climbing or banking. You derive your rate of climb (or descent) or descent from your altimeter. Your bank rate from your rate of turn indicator. These are reliable and accurate instruments. They are not affected by UAS. Anyone who doesn't rely on their instruments ends up in a dangerous situation.

[airtren]

I'm just here to make sure that press-induced falsehoods about the design, including but not limited to it being "designed to take pilots out of the loop", "the first step in replacing pilots", "designed by managers and computer nerds without pilot input" and "reliant on the French Government covering up the real reasons for accidents" meet with robust and evidence-supported rebuttal. Any or all of which are not only substantively untrue, but also defamatory against the hard work of all the teams that have worked on it over the years, some of whom are no longer with us.


The danger of one taking himself waaay tooooo seriously is the exhibiting of ridiculous patronizing attitudes.


In this case, aside from the pitot tube issues (which are serious, and Airbus/AF have some 'splaining to do there...), it's looking increasingly likely that there were no hardware (or indeed software) faults involved in the crash of AF447. The "enhancements" of the next versions/generations speak and will speak by themselves.

It's not about the manufacturer ... it's about demanding a degree of factual basis behind the discussion
Your very recent posts, like many in the past, on the SS topic are another crude example of your ignoring factual elements, and not producing any countering factual elements, at a "n" iteration.

It does not really matter if it's caused by a lack of comprehension, a lack of technical expertise, or ill intentioned tactics. The predominant appearance of spreading a smoke screen over a few problems is counter productive not only for those very few problems, but the entire Airbus technology, as it reflects badly on the many things that are good.

[airtren]

The Red Herrings become a shoal. Direct v Indirect input now.


No.

It's not Direct or Indirect Input.

It is perhaps too abstract, and a terminology that is not part of your profession.

It is Direct versus Indirect Information Transfer.

If B is interested in information about A, it can have a Direct information exchange from A to B, which is not altered by any intermediate agent.

An Indirect information exchange involves one or more intermediate agents - let's say C, D, E, F, G. Each intermediate agents transform, translate, or process the information as part of the transfer. C, D, E, F, and G transforming, translating, or processing, is introducing distortions, and errors. Consequently, when the information arrives to B from A, via C, D, E, F, and G, it can be distorted or altered significantly.

... Instruments, AirTren, instruments are the key.
They are not fooled by panic, tension, stress or any of the other factors which so much mess up human perception.

No.

The KEY is the visual contact, the visual perception.

In case of a blinding attack, the instruments are not good at anything.

The panic, tension, stress, are affecting the visual perception.

Instruments can be inaccurate, can be fooled. They show data collected by sensors, processed by sensor data processing units, and as such they can be fooled by malfunction of sensors, by margin of errors in the processing algorithms, etc... This was the case with the AF447 out of specs AOA.

See also Machinbird's post.


They can be relied on to give an accurate reading of a situation provided you remember your training and cockpit drills. No need to look at the yoke or whatever, look at your instruments. You're missing the point, you're missing the difference between Direct and Indirect Information Transfer.

The direct visual contact of the PNF with the PF's SS, yoke, or whatever other control mechanism is in the cockpit, is a Direct Information Transfer - from A (SS of PF) to B (PNF).

The reading of instruments, is Indirect Information Transfer - from A to B, via C, D, E, F, G etc.... , because, the instruments don't show directly the PF actions on the SS, but rather the effects of the PF's SS actions onto the deflective surfaces, along with effects onto the A/C attitude, A/C speed, etc,... (which combine other controls, like throttle, trim, etc...) Information about those effects is collected by the A/C sensors, each sensor with its margin of errors, and passed to the sensor data processing units, and so on, (with each sensor data processing algorithm having its own margin of errors).....

Finally, the PNF reading the instruments need to make a mental translation of the instrument readings into PF SS actions. For accuracy,
the PNF need to exclude the effects of the PF actions on Throttle, or trim, or others... That is in fact impossible....

As you can see - if you're willing to - the Indirect Information Transfer is not only so convoluted, that by now, we've probably forgot that the PNF was just interested in the PF's actions onto the SS,.... but it is introducing the effects of other controls than the SS, which is impossible to determine only from a reading of the instruments......:ugh:

[OK465]

CONF:

With the SS full forward, I would expect the elevators to be full leading edge up for a simulator full nose down command, and be displayed as such on the SD.

One then would in general expect the nose of the simulator to follow this command. Why it didn't in the 330 and evidently did in the 320 is what's at issue.

As far as SS commanded proportional 'G' and the THS, what was the 'G' indication in the Flight Data block during the full nose down SS command prior to manual re-trim?

:)

[Old Carthusian]

I am afraid you misunderstand the situation - it is not about information transfer it is about information interpretation. How you judge the information you receive is the important factor. A yoke does not add any advantage because the interpreter of the position may well differ in where he sees the position of the yoke and the threat or otherwise it represents. If you think of visual perception as reliable I would point out that an instrument is a much more likely to be read reliably than the position of a yoke.
Now I assume you are not a pilot otherwise I would not need to explain this. At night without any visual references it is easy to become disoriented. This is where the aircraft instruments come into play. Running off separate reliable mechanical or electronic inputs they give an accurate and measured stream of information which a trained pilot can use to fly an aircraft safely. If one instrument does prove to be unreliable then there is enough redundancy in the others to enable the pilot to fly the aircraft smoothly. It is important to remember that the instruments are not an indirect transfer but a reliable indicator of the state of the aircraft at the time. Over many years instruments have been refined so that they are more accurate than human perception.
Of course to use your instruments requires training and cockpit discipline. The mode of input for control directives is actually irrelevant and comes down to preference. Your direct v indirect information transfer is one of the shoal of red herrings. It falls at the hurdle of interpretation. There is clear evidence that the PNF was aware what was happening with the aircraft. How was this - he couldn't see the sidestick but he could see the instruments and they gave him the information he needed. His actions and later perceptions were not sufficient but this does not alter the fact that he knew there was something wrong very rapidly. The PF does not seem to have looked at his instruments at all and this is a clear training failure for which the airline must also be held responsible.
You also owe Dozy an apology - of the non-pilots he is perhaps the one who has understood the dynamics of the accident clearly. It was human generated in a situation which was clearly survivable if the crew had been adequate.

[Zorin_75]

Those that have not flown FBW still need to realize that even in the Airbus "direct" law, the computers still modify the control surface deflections and deflection rates. To wit from FCOM manual I have:So let's get to the point.
Is it your opinion the pilots were trying to do the right thing but the flight control computers, "HAL" if you insist, grabbed their arm and didn't let them?
If so, please point out where, as it would be a serious factor in AF477 and definitely should be discussed here.
Otherwise, maybe a separate general FBW thread would be a more fruitful place for a discussion of these matters?

[RetiredF4]

Quote:
Confiture
2 PNF knew the PF was making inputs - Did they know which inputs he was making ?

Answer Old Carthusian
Yes by looking at the instruments. An input produces a certain pattern on your instruments and you can understand what your aircraft is doing.
Would you explain yourself in relation to the timeframe starting from 02:12:45?

Retired F4

Stick was full left, aircraft was banked to the right, how do you know by instruments, what kind of inputs are made by the guy in the dark 1 meter away?

Answer Old Carthusian
Retired F4
Both the PF and PNF have displays with the same instrumentation on them. Your artificial horizon will tell you if the plane is climbing or banking. You derive your rate of climb (or descent) or descent from your altimeter. Your bank rate from your rate of turn indicator. These are reliable and accurate instruments. They are not affected by UAS. Anyone who doesn't rely on their instruments ends up in a dangerous situation.

Why not answer my question, which you yourself raised with your answer? We are not talking about instrument flying and its carrying water to the sea to try to teach me how it is done. All of my 3.336 instrument approaches where handflown from start to end and successful terminated. Most of them in german wx conditions, not under the sun of california.

The discussion is about recognizing actions (not outcome) of handling flight control inputs in a non normal situation like AF447 was in.

I did lots of instructing in the backseat of the F-4. Our sticks had been interconnected and i could feel through critical maneuvers. Let us look at stall approaches, where a wrong flight control input lead to departure. On the stick the wrong input could be felt and corrective action could be taken immidiately and thus departure prevented, whereas on the instruments the faulty input would show later, when the faulty input had already lead to departure and uncontrolled flight. Better to be one step ahead than one step behind.

In the case of AF447 at 02:12:45 the PNF and the captain had been both aware of the right bankangle and gave instructions to the PF to correct that bank as they could not observe any action of the PF to correct this bank on the instruments. In reality the PF was aware of the same fact and told them, that he already had full left SS without success. That information was vital as it showed, that correction with aileron alone did not work and helped the captain to refocus on solving the bank problem with rudder input. It took considerable time to unmask this information and it was not visible on any kind of instruments.

DW
The precise position of the stick is considerably less important than being able to work out that the stick is not where it should be. Once that is ascertained, then the only logical recourse is "I have control".

It can be assumed, that had the PNF took control of the aircraft prior receiving this information at 02:12:45, that he as well would have used aileron firsthand and would have lost valuable time as well.

I never said, that the SS should be replaced by a yoke, but i do not turn a blind eye to the fact, that in this stressfull situation the awareness of the crew concerning the behaviour of the aircraft in relation to the flightcontrol inputs of the PF was totally lost, that the captain was not able to grasp the situation when he came back to the cockpit and that the mentioned timeframe starting at 02:12:45 is a master example for the lack of direct feedback. Not that this is the only situation in these horrible 4 minutes, there are others as well. It is only a question of perspective.

[Clandestino]

... or 02:11:55 when the pitch is 10 deg below horizon ... where is the stick Old Carthusian ... !?

Right SS - full back, left SS - neutral. Do you understand why the aeroplane pitched down even with full back sidestick, full NU elevator and THS in heavy nose up position, increasing towards stop?

In the case of AF447 at 02:12:45 the PNF and the captain had been both aware of the right bankangle and gave instructions to the PF to correct that bank as they could not observe any action of the PF to correct this bank on the instruments. In reality the PF was aware of the same fact and told them, that he already had full left SS without success. That information was vital as it showed, that correction with aileron alone did not work and helped the captain to refocus on solving the bank problem with rudder input. It took considerable time to unmask this information and it was not visible on any kind of instruments.Do you understand why the crew had what you call "bank problem"?

[RetiredF4]

Clandestino
Do you understand why the crew had what you call "bank problem?

I do.
But please tell me your oppinion and how it would influence the discussed matter concerning recognition of correct or incorrect SS input as discussed.

[Old Carthusian]

Retired F4

I would hesitate to compare an F4 with an A330.

[Clandestino]

I do.
But please tell me your oppinion and how it would influence the discussed matter concerning recognition of correct or incorrect SS input as discussed. Could you please provide your explanation behind "I do"? Methinks that therein lies the problem but I wouldn't like to waste bandwidth by going tangentially.

[RetiredF4]

Clandestino
Could you please provide your explanation behind "I do"? Methinks that therein lies the problem but I wouldn't like to waste bandwidth by going tangentially.


http://www.pprune.org/tech-log/468394-af-447-thread-no-7-a-3.html#post6799108

And feel free to PM me, that way we may waste time, but no bandwith.


OldCarthusian
Retired F4
I would hesitate to compare an F4 with an A330.

I would too, therefore i was not tempted to do it.

[airtren]

I am afraid you misunderstand the situation - it is not about information transfer it is about information interpretation....... etc, etc...


Your reply to my post, the wrong references or repeats of my text, show that you don’t see, can’t see, or not want to see what I pointed out.


With the current location of the SS in the A330 cockpit, and lack of ability to have visual contact with it, it is not possible to a PNF and NF Captain to ascertain with good precision the SS position, and PF's actions on the SS. Several suggestions of resolving this without replacing the SS with a yoke were made even on this Forum – NO, it is not the use of instruments, which is wrong for reasons I will not repeat.



From a system architecture perspective, the cockpit is a critical system application, and in such an application having a virtual wall of secrecy around one of the main controls, like the A330's SS, is a NO-NO. It’s a NO-NO, as it is a NO-NO in the Control Center of a Nuclear Power Plant, or as it is in the Control Center of a large cargo ship, or a very large crane operated by a crew, to name a few. In all of those, there are instruments, like in the cockpit, but the controls are not hidden, from the crew present in the control center. As some A/C cockpits do not have this problem, the lack of consistency in the airline industry, may be favored by the lack of regulation in this respect.



The AF 447 accident was caused by the confluence of multiple factors, that span a wide spectrum, which include a few manufacturer problems, which are revealed only in such extreme cases, as the AF447.

While the information made public will be shaped to minimize public perception impact, it’s likely every organization will do its best to address the problems, even if they are not spelled out straight forward in an official report. As far as the design goes, as I mentioned, new versions/generations will speak by themselves of the problems, and their solution.

[Clandestino]

Thanks for the link, Retired F4.

Great. So you recognize that aeroplane was stalled yet keep on drumming on roll behaviour. For Finnegan's sake, can you picture A330 flying at 40° AoA with about 100 KTAS? Ugly, eh? Spoilers are blanketed by wing, rudder is blanketed by fuselage and ailerons don't have much say - going up they're in wings wake, going down makes a bit of difference but very low forward speed makes them not particularly efficient.

What the heck does sidestick have to do with behaviour of aeroplane that is at extreme AoA, beats me. Oh yes - there's a theory that with yoke somehow CM1 would recognize that CM2's control inputs do not have much effect on aeroplane so he would recognize that the aeroplane is stalled and that first and foremost is AoA reduction.

Well, I'm not buying it. He was listening stall warning for 54 seconds and made not a comment about it, let alone done something.

So far, I have found two fuel sources that keep this Hamsterwheel turning

1. People having no grasp of aerodynamics, instrument flying or aeroplane system making elaborate analysis of some technical detail. Not able to take subtle hints their theories are spectacularly flawed, they resort to personal attacks when told so in no uncertain terms.

2. People that have some idea how flying works, take out a detail out of whole picture then trying to reconstruct the whole scene just on that little detail. That their picture bears not much resemblance to original seems not to bother them much.

[gums]

Salute!

@ Zorin

Sorry if I did not my point clear.

- My main point is that even in "direct" law the elevator does not follow the stick inputs as most think. And I am also not sure that "gains" and rates for the ailerons are eliminated.

- I do not feel that the reversion sequence is clearly understood until one goes thru it many times and notes what's protected, what isn't and actually sees/feels the results of control inputs. My personal preference would be to have only one "alternate" law, then "direct" law, and the THS would require manual settings in both.

- The auto-trimming of the THS did not "help". The pilot would have had a harder time holding the AoA and pitch attitude if the THS had stayed where it was when air data went awry. So in that regard I DO THINK the computers got in the way.

Simply stated, I lay most of the fault with the crew but can not rule out contributions by some of the 'bus FBW and display/warning implementations.

[DozyWannabe]

@CONF:

By attempting to force me into the debate on your terms, I think you'll find that it is you who is arguing like a politician. I've already stated numerous times that I don't want to go there again because we've already been there before - you *know* we've been there before, and because I've stated my position that I don't think it's relevant to this case I think it's only fair that is accepted.

Probably going to take a break for a while after this, as it appears the thread is being sucked into the old "interconnected" debate for something like the fifth time, but just to summarise:

Based on historical data, we have incidents where inappropriate backpressure following UAS has occurred on aircraft equipped with interconnected yokes and independent sidesticks, most of which have led to an airframe loss. We also have historical data that proves lack of interconnection is no barrier to recovery (specifically the other 30-or-so A330/340 incidents which did not lead to a crash). That suggests to me that any round-robin discussion of interconnection vs. independence is not relevant to the case at hand, which is why I'm not going to get involved any further there.

Yes, the Airbus sidestick design drops the tactile feedback channel, but whether that is a big deal or not largely depends on your opinion. Some pilots who have grown up flying on feel distrust the design, and they wouldn't be human if they didn't. From an engineering standpoint most of the reason for having interconnection (i.e. the ability to apply extra leverage from the second pilot in the old cable days) was gone by the time controls became fully-hydraulic over 40 years ago. The yokes are cumbersome, and inadvertent bumping or moving of the columns have led to several incidents over the years, some of them fatal. The Airbus engineers ran the sidestick design past the pilots (at least one of whom was the most respected safety pilot in the world at the time) and got approval. Muddying the issue was the rise in automation during the '70s and '80s and a lot of people got their wires crossed - not helped by the press, who always like a "let's you and him fight" situation.

To my mind, this is irrelevant in this discussion for the reasons I laid out in my third paragraph, and what makes it more so is that while arguing over whether having a badly-positioned yoke in front of him might have made the PNF react more decisively, the thread is missing the point that neither of the F/Os at any point seemed to acknowledge that they were in a stall, and without that it's arguable that even if the PNF had taken control he might not have been able to recover in time.

The reason I say this comes from my sim session, which taught me some things I didn't know - namely that when stalled, the tendency is for the aircraft to respond to aileron input with a roll in the *opposite* direction, and as such it is advisable to use the sidestick for pitch only and to control roll with gentle rudder, which took less than 30 seconds to explain (albeit several attempts for my lead feet to get right :) ) - but if we are to believe what the BEA is saying then this little bit of life-saving knowledge was something that these professional line pilots had never been told, or at least not recently.

So (sorry for the lengthiness of this rant), Air France was routinely sending up 3-man crews, two of whom had no manual handling instruction at high altitude, in a type that they were aware had a known problem with the pitot tubes that in a worst-case scenario would force the handling crew into handling the aircraft manually at altitude. That's almost priming the system for an accident eventually, and no amount of debate over automation or interconnection will alter that fact. Whether Air France were alone in this practice (I suspect they weren't), they were the ones who ended up with the bad cards and had the accident and in my opinion it is they who should shoulder the lion's share of responsibility for allowing it to happen. I think "blame" is a non-helpful concept in aviation accident investigation and I'm not a fan of the continental practice of making it a judicial matter because it makes getting at the truth problematic (although, truth be told, the Anglo system is much the same but handled by the civil courts).

@gums - I can assure you that once the aircraft stops responding in the manner you expect, the last thought on your mind should be what is protected and what isn't - it's safest to assume that nothing is protected and the utmost caution be taken to get your response right.

Safe journeys folks.

[Lyman]

Dozy. You're last paragraph re: pilots/Air France. Excellent. It pulls together a major portion of the impetus for disaster we see in this tragedy. I completely agree. Allow me a small addition? With the stage set for LOC in manual under these conditions, (and they were stinko), Airbus shows a remarkable blind spot in monitoring their product whilst in service. This is not a third world fifth owner operator, it is a legacy Flag Carrier.

Wildly expensive and complicated machine systems need nurture. In seeing to it that her operators were allowed singly to abuse her care and operation was a major player in her demise. Her makers lost the marque.

If one truly believes that as automatics increase in capability, Pilotage can degrade, the coffin business will bloom, leastwise whilst airborne.

[Machinbird]

Well, I'm not buying it. He was listening stall warning for 54 seconds and made not a comment about it, let alone done something.1. People having no grasp of aerodynamics, instrument flying or aeroplane system making elaborate analysis of some technical detail. And some people have very little grasp of the varied ways in which people gather and process information. :rolleyes:

but if we are to believe what the BEA is saying then this little bit of life-saving knowledge was something that these professional line pilots had never been told, or at least not recently. There have to be a whole lot of jet pilots who have never flown a swept wing jet at very high & at stalled AOA. They have been spending their lives avoiding just that situation.(Non-tactical flying)

A swept wing jet does not behave like a straight wing trainer at high AOA. The dihedral/roll effect from the swept wings is very powerful, particularly at high AOA.

[jcjeant]

Hi,

The reason I say this comes from my sim session, which taught me some things I didn't know - namely that when stalled, the tendency is for the aircraft to respond to aileron input with a roll in the *opposite* direction, and as such it is advisable to use the sidestick for pitch only and to control roll with gentle rudder, which took less than 30 seconds to explain (albeit several attempts for my lead feet to get right http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/smile.gif ) - but if we are to believe what the BEA is saying then this little bit of life-saving knowledge was something that these professional line pilots had never been told, or at least not recently.
I don't buy any A330 simulation of stall like you don't buy a cat in a bag
The real thing (full stalling) was never tested on the A330
This was not made cause certainly was taken in account the risk and money
So the choice was to not put in danger the life of a test crew and the risk to loss a frame .. but this imply to put the life at risk of the line crews and the passengers in case of a stall .. as the pilots don't know how the plane will really act at the eventual recovery manoeuvres
Very bad choice
It's really a big issue in the aircraft industry to not perform all the needed tests .. and this not only apply to the planes but also for the parts used
The life boats of the Ocean Ranger (drill rig) where tested many time by nice weather and all was good
When the tragedy was there .. the life boats were pushed by the wind against the columns of the rig .. were crushed even before touch water .. killing all people in
The design of survival gear was not good (location) for bad weather .. but this kind of situation was never tested
Heuristic ?

[airtren]

...
Based on historical data, we have incidents where inappropriate backpressure following UAS has occurred on aircraft equipped with interconnected yokes and independent sidesticks, most of which have led to an airframe loss. We also have historical data that proves lack of interconnection is no barrier to recovery (specifically the other 30-or-so A330/340 incidents which did not lead to a crash). That suggests to me that any round-robin discussion of interconnection vs. independence is not relevant to the case at hand, which is why I'm not going to get involved any further there.

First, this paragraph creates a wrong equivalence, by generalizing and taking historical/statistical data out of the very specifics of the context of each case.

Then, the paragraph is diffusing, or blurring the main point from the "visual contact", and/or "virtual secrecy" of the placement of the A330 SS, which is the problem pointed out by several posters, to "interconnection" and "independence", which no-one mentioned other than you.

Addressing the "visual contact"/"virtual secrecy" would be a lot more helpful in converging on this discussion....


...The Airbus engineers ran the sidestick design past the pilots (at least one of whom was the most respected safety pilot in the world at the time) and got approval.It's "the placing of the SS" that makes visual contact with it impossible, not the "SS". The paragraph is another example, mentioned before, of extrapolating or extending one problem of a mechanism, to the entire mechanism, or system, which creates the road blocks of being able to converge in this discussion.


...while arguing over whether having a badly-positioned yoke in front of him might have made the PNF react more decisively, the thread is missing the point that neither of the F/Os at any point seemed to acknowledge that they were in a stall,......while the more decisive reaction is emphasized correctly, the paragraph is missing the point that an earlier and more effective correct action of the PNF could have prevented the Stall, during approach.... or could have made the recovery from Stall possible....


.... Air France was routinely sending up 3-man crews, two of whom had no manual handling instruction at high altitude, in a type that they were aware had a known problem with the pitot tubes that in a worst-case scenario would force the handling crew into handling the aircraft manually at altitude. That's almost priming the system for an accident eventually, and no amount of debate over automation or interconnection will alter that fact. Whether Air France were alone in this practice (I suspect they weren't),...
Of course they weren't, ....

What Air France, or others did, while being "a cause", is in fact, also "an effect".

Why did they do that? what is the cause? what put them at ease, that it is possible to do that without significant risk?....

[Organfreak]

Answer Old Carthusian:
Yes by looking at the instruments. An input produces a certain pattern on your instruments and you can understand what your aircraft is doing.


Two points to keep in mind:
-There is no record of what was displayed to the PF, and thus, no proof that he had all the info he needed on his displays. There is no reason to "know" either way if he had working displays. (As we all know, pilots have vigorously resisted the suggestion to install video cameras on the flight deck, just as they resisted the addition of CVR at one time.)
-It hasn't been determined, and probably cannot be, what the poor PF meant when he said, "We have no more indications." Correct me if I'm wrong, but I believe that many here have interpreted that to mean "no speed indications." There's no reason to assume that as gospel.
-Oh, here's a bonus third point! If PF had had a working AoA display, and he had looked at it, ya never know that 228 people might still be walking the earth today.

airtren said:
The AF 447 accident was caused by the confluence of multiple factors, that span a wide spectrum, which include a few manufacturer problems, which are revealed only in such extreme cases, as the AF447.

I'm weighing-in in support of what airtren, Machinbird, and F4 have been trying to say. As a dispassionate observer, their views make the most sense to me, and I have no AB, FBW, or Boeing axe to grind. Suggestions that such contributors are prejudiced or "anti-AB" are simply paranoid, in my view. (See airtren's comment above.) Anyone unwilling to weigh ALL possible factors is not being intellectually honest, yeah you, DW! :p

[RetiredF4]

Let me use some more bandwith then.

Great. So you recognize that aeroplane was stalled yet keep on drumming on roll behaviour.

Read my post. I did not do that.

For Finnegan's sake, can you picture A330 flying at 40° AoA with about 100 KTAS? Ugly, eh? Spoilers are blanketed by wing, rudder is blanketed by fuselage and ailerons don't have much say - going up they're in wings wake, going down makes a bit of difference but very low forward speed makes them not particularly efficient.

I´m fully aware how a basic aircraft works or better not works in a stalled condition, they are all similar. ANd i needed no sim time in a A320 like DW to know what ailerons do in a stalled condition.

What the heck does sidestick have to do with behaviour of aeroplane that is at extreme AoA, beats me.

Nothing at all. Could you quote me where i made such an mistake?

Oh yes - there's a theory that with yoke somehow CM1 would recognize that CM2's control inputs do not have much effect on aeroplane so he would recognize that the aeroplane is stalled and that first and foremost is AoA reduction.

Is that your theory? Amazing. I only used it as an example to answer OC´s statement, quote below.

Quote:
Confiture
2 PNF knew the PF was making inputs - Did they know which inputs he was making ?

Answer Old Carthusian
Yes by looking at the instruments. An input produces a certain pattern on your instruments and you can understand what your aircraft is doing.

Retired F4
Would you explain yourself in relation to the timeframe starting from 02:12:45?

Not more and not less. By the way, i still wait on the answer to my question, how the PF or the captain could have seen on the instruments, that despite the continuous right bank PF had full left SS.

Or is this answer no longer relevant as it does not fit in the "everything is right, nothing needs to be changed" scheme?


Well, I'm not buying it. He was listening stall warning for 54 seconds and made not a comment about it, let alone done something.

The simple answer is he should have failed his medical previously due to a hearing problem, or he wanted to kill himself, or....
what is your answer?

So far, I have found two fuel sources that keep this Hamsterwheel turning

1. People having no grasp of aerodynamics, instrument flying or aeroplane system making elaborate analysis of some technical detail. Not able to take subtle hints their theories are spectacularly flawed, they resort to personal attacks when told so in no uncertain terms.

2. People that have some idea how flying works, take out a detail out of whole picture then trying to reconstruct the whole scene just on that little detail. That their picture bears not much resemblance to original seems not to bother them much.

Now where do i fit in?

I like the term KISS, but not in the cause of accidents. I like to turn every stone and look under it, and most of the people you acuse to turn the hamster wheel do the same. Its collecting bit for bit, some turn out to be one way streets, some need further consideration.

I take out a detail and discuss it, but the reconstruction will need lots of those details to get the picture complete. To cry out loud when one of those details is discussed that this is against A or that the whole accident is hung on one single nail is tiring.

I for myself leave it anyway to BEA and Airbus and whatever agency is responsible to make the final saying. But that does not keep me from telling my oppinion on certain aspects of this accident.

But if you do not like this "hamster wheel" then it would be very simple to just stop reading it.

[Mr Optimistic]

Interesting reading but the strong inference must remain that the 3 crew at no time seriously considered that they were stalled and at no time applied appropriate inputs to attempt to address a stall. Can't see how yoke/aoa gauges are relevant. Perhaps they would have made a difference, we can never know, but they should not have been needed in any case. Dialogue articulating the pull-up inputs is clear enough on the transcripts so can't think anyone was seriously misunderstood for any appreciable period.

Had the situation finally been appreciated and the subsequent recovery hindered through lost time or absence of some instrument, OK. But it never got to that point.

[Clandestino]

My main point is that even in "direct" law the elevator does not follow the stick inputs as most think.Problem one: those "most" include the ones who designed Airbus, the ones who certified and the ones who fly it. Direct law in pitch is proportional stick-to-elevator displacement.

Problem two: AF447 went into ALT2 so it wasn't in direct pitch. To oversimplify: ALT2 in pitch is basically G demand. That the aeroplane remained in ALT2 is indication inertial reference was working.

Problem three, which really is mostly limited to fora: Airbus control laws are difficult to understand for someone with just a passing interest in aviation. Those with dedication and capability can master them without giving too much thought to them. Bad news is that not everyone can be an airline pilot. Good news is: those who really can have extremely good chances of getting to grips with Airbus.

Yes, the Airbus sidestick design drops the tactile feedback channel, but whether that is a big deal or not largely depends on your opinionOpinion of certifying authorities is that it matters not.

when stalled, the tendency is for the aircraft to respond to aileron input with a roll in the *opposite* direction, and as such it is advisable to use the sidestick for pitch only and to control roll with gentle rudderCorrect for almost any aeroplane. Caveat is that it works as long as there is enough rhoveesquared and controls are not blanketed. No transport aeroplane has ever been put intentionally far beyond stall AoA therefore while sim behaviour is extremely realistic just above stall AoA, it turns into guesswork as AoA is increased, which is not a problem at all. Sims, just like aeoplanes, re not meant to be operated outside the envelope.

but if we are to believe what the BEA is saying then this little bit of life-saving knowledge was something that these professional line pilots had never been told, or at least not recently.Say what?!? Professional line pilots are trained to avoid stall, roll control via rudder while stalled is domain of flight testers and those bent on serious aerobatics! Life saver would be push forward!

Air France was routinely sending up 3-man crews, two of whom had no manual handling instruction at high altitude, in a type that they were aware had a known problem with the pitot tubes that in a worst-case scenario would force the handling crew into handling the aircraft manually at altitude. That's almost priming the system for an accident eventually, and no amount of debate over automation or interconnection will alter that factSo? There are thirty-seven cases of unreliable airspeeds on 330/340 aeroplanes listed in interim2. Companies are de-identified, however, given registration and date, it is easy to find out who was the operator at the time of the incident. On a few occasions it was AF crews, that despite having no training at manual handling, actually lived through the experience. This might lead the AF into believing that all of their crews would cope with the problem under any circumstances.

Of course, it would be mistake to interpret this as "It was deceased pilot's fault". There definitively were organizational precursors but pilots were not lambs lead to slaughter by tricky aeroplane and inadequate training.

And some people have very little grasp of the varied ways in which people gather and process information.There are strict demands how one who wants to fly and avoid getting killed flying has to "gather and process information". As I said: not everyone...

By the way, i still wait on the answer to my question, how the PF or the captain could have seen on the instruments, that despite the continuous right bank PF had full left SS. He couldn't. No one flying FBW Airbus can know what exactly is his significant cockpit other doing with the stick. If it's such a big deal, why would it get overlooked by those allowing thousands of Airbi flying passengers commercially?

[CONF iture]

By attempting to force me into the debate on your terms, I think you'll find that it is you who is arguing like a politician. I've already stated numerous times that I don't want to go there again because we've already been there before - you *know* we've been there before, and because I've stated my position that I don't think it's relevant to this case I think it's only fair that is accepted.
Relevant or not is not my question.
I don't force you to anything - If you have nothing to argument you don't have to write that long either.

At least I'm not the only one to perceive what I would qualify also as intellectual dishonesty.
I'm weighing-in in support of what airtren, Machinbird, and F4 have been trying to say. As a dispassionate observer, their views make the most sense to me, and I have no AB, FBW, or Boeing axe to grind. Suggestions that such contributors are prejudiced or "anti-AB" are simply paranoid, in my view. (See airtren's comment above.) Anyone unwilling to weigh ALL possible factors is not being intellectually honest, yeah you, DW!

Probably going to take a break for a while after this
I also think you need one.

[Organfreak]

Mr Optimistic said:
Interesting reading but the strong inference must remain that the 3 crew at no time seriously considered that they were stalled and at no time applied appropriate inputs to attempt to address a stall. Can't see how yoke/aoa gauges are relevant. Perhaps they would have made a difference, we can never know,

First, ND input was tried (for not long enough) but it brought the stall warning back on. That may not be a good excuse but it is perhaps a REASON.

"We can never know" if an AoA indicator would have helped. And there, you've made my case, thank you. Likewise, we "can never know" whether-or-not seeing a yoke buried in his lap might have helped PFN come to a realization. In other words, you who insist that some of these things made no difference really have no solid evidence for those claims. Pure opinion.

Of course, there is no such thing as foolproof, but should we not err on the side of making the Airbus as "foolproof" as possible? Of course we should. Why shouldn't pilots have every possible tool in their box, given the many opportunities here for profound confusion?


Originally Posted by DozyWannabe
Yes, the Airbus sidestick design drops the tactile feedback channel, but whether that is a big deal or not largely depends on your opinion


To which Clandestino offered:
Opinion of certifying authorities is that it matters not.

Well sir, now that we have AF447, maybe they will reconsider, eh? Are certifying authorities always right the first time?
Where is the icon for 'pppfffttt!'?

[TTex600]

Interesting reading but the strong inference must remain that the 3 crew at no time seriously considered that they were stalled and at no time applied appropriate inputs to attempt to address a stall. Can't see how yoke/aoa gauges are relevant. Perhaps they would have made a difference, we can never know, but they should not have been needed in any case. Dialogue articulating the pull-up inputs is clear enough on the transcripts so can't think anyone was seriously misunderstood for any appreciable period.

Had the situation finally been appreciated and the subsequent recovery hindered through lost time or absence of some instrument, OK. But it never got to that point.

Thank You. In all of the techno babble, "sim-geek", bovine scat, the fact remains that the crew saw something that convinced them to ignore a stall warning. Either they were incrediblly stupid, or incrediblly confused by what they saw, felt and heard. No amount of FBW, SS, automation, defense changes the fact that three qualified aviators flew the bird into the ocean. What I find disturbing is that the airplane (AB) was designed to prevent such an event, but failed.

[Machinbird]

Interesting reading but the strong inference must remain that the 3 crew at no time seriously considered that they were stalled and at no time applied appropriate inputs to attempt to address a stall. Can't see how yoke/aoa gauges are relevant. Perhaps they would have made a difference, we can never know, but they should not have been needed in any case. Dialogue articulating the pull-up inputs is clear enough on the transcripts so can't think anyone was seriously misunderstood for any appreciable period.

Had the situation finally been appreciated and the subsequent recovery hindered through lost time or absence of some instrument, OK. But it never got to that point. The lead up to the stall almost certainly had to result from mental processing overload on the PF, and a hesitancy to act on the part of the PNF.

I agree that none of the 3 in the AF447 front office seem to have acknowledged or verbalized a stall (According to the released transcript). I have to assume that once stalled, the experience was too far from their training to recognize and would therefore have had to be puzzled out on an intellectual basis for a successful outcome.

Mixing the discussion of yoke vs stick and presence of AOA is like mixing oil and water.
If you had ever flown with an AOA gauge, had observed one in various flight regimes and in the Sim, and had became comfortable with the veracity of the indication, then when the stall warning began to squawk, your eyes would be programmed to look at the AOA indication for confirmation, particularly when the airspeed is no longer available in front of you. As long as AOA is moving in response to control motions, the operational assumption should be that it is valid (operational assumption = bet your posterior on it).
If the AF447 crew had an AOA indication and had been trained to use it, the only valid explanation for allowing the stall would be a death wish or both pilots sleeping.
There is a world of difference between stall warning and AOA.

[lomapaseo]

What I find disturbing is that the airplane (AB) was designed to prevent such an event, but failed.

Let's be careful about the semantics lest somebody starts believing these words.

The aircraft is designed with the means to have prevented this event.

It is not designed with the pilot out of the loop.

[Organfreak]

Machinbird uttered:Mixing the discussion of yoke vs stick and presence of AOA is like mixing oil and water.

Sorry, Mr. Bird, I had no intention of conflating the two things. What I intended to say is that they both share the attribute of "might have helped, who knows?"

The rest of your comments about AoA indicator are spot on and exactly what I meant but didn't have the skills to say so.

[Machinbird]

Quote:
Originally Posted by Machinbird
And some people have very little grasp of the varied ways in which people gather and process information.

Clandestino
There are strict demands how one who wants to fly and avoid getting killed flying has to "gather and process information". As I said: not everyone...So, are you suggesting that the crew for AF447 were not properly selected....?

[jcjeant]

Hi,

Clandestino
Problem three, which really is mostly limited to fora: Airbus control laws are difficult to understand for someone with just a passing interest in aviation. Those with dedication and capability can master them without giving too much thought to them. Bad news is that not everyone can be an airline pilot
So .. are the AF447 airline pilots or not ?

Clandestino
This might lead the AF into believing that all of their crews would cope with the problem under any circumstances. Heuristic ... the good choice for evaluate a problem ?

Clandestino
He couldn't. No one flying FBW Airbus can know what exactly is his significant cockpit other doing with the stick. If it's such a big deal, why would it get overlooked by those allowing thousands of Airbi flying passengers commercially? Heuristic .. again
Heuristic is a invite to disaster

[CONF iture]

Your artificial horizon will tell you if the plane is climbing or banking.
Certainly not.
If it was true AF447 would have landed at CDG.

[Old Carthusian]

The shoal continues to multiply. Gentlemen this accident is about perception and psychological factors. It is nothing to do with the machine. I have consistently mentioned 'Know your machine'. In my view, the flight crew didn't and here I have to break cover. In my view they were incompetent and unsuitable to be flying an aircraft - their lack of professionalism and disregard for the procedures caused an accident in a recoverable situation. In my view they were part of a culture that had developed in Air France based on arrogance and casualness. I referred some threads ago to the Clipper Skipper syndrome - pilots who could do no wrong and didn't have the skills needed. Some of you should go and read up on the Pan Am accidents in the 1970s. In my view Air France their airline cut training and ignored important aspects of flying - they also are culpable.
As for the arguments that the instruments are unreliable I have never seen so many straws being grasped in one go. Read the reports again - the instruments were functioning effectively. It was the flight crew who didn't know what to do. NO CRM, No SOPs, No UAS procedure just frozen incomprehension. A yoke wouldn't have helped here at all. NO training, No chain of command. This is a human disaster not a machine failure. We must be realisitic here this is a pilot failure brought on by poor procedures. This was not an extreme case - this was an unusual situation which could have been recovered and has been in other situations. AirTren talks about information when perception is the key. Why did the crew ignore the stall warning? Why did they ignore their reliable instruments? They were not up to the job - that is the real cause of the accident.

[CONF iture]

Right SS - full back, left SS - neutral. Do you understand why the aeroplane pitched down even with full back sidestick, full NU elevator and THS in heavy nose up position, increasing towards stop?
I doing ok Clandestino, thanks, Old Carthusian may now realize that instruments don’t necessarily tell what the flight control inputs are …

Now for you Clandestino :
You are the Captain on AF447, as you enter the flight deck the stall warning stops, the pitch is going down.

The equipment is a A-330, you don’t know for sure which pilot has control and don’t know which inputs are applied.
The equipment is a A-310, you see the right seater with 2 hands on the control wheel to maintain it to his stomach for half a minute.

Which scenario do you consider the most informative for you ?

[Old Carthusian]

Instruments are more reliable than human perceptions Conf iture and I haven't changed my opinion one bit. Certainly not on the spurious irrelevancies that have been presented so far.

[CONF iture]

Instruments are more reliable than human perceptions Conf iture
Who said otherwise ?

[Old Carthusian]

AirTren, retired F4 to name a couple. Those who argue that a yoke would have helped. By implication you yourself (and I do apologise if I have misread your posts) also seem to think that

"Old Carthusian may now realize that instruments don’t necessarily tell what the flight control inputs are"

Instruments do precisely that because that is what they are designed to do.

[CONF iture]

To my knowledge those guys have never pretended that "Instruments are more reliable than human perceptions" but I will let them reply.

"Those who argue that a yoke would have helped"
I am positively one of them.
Note : I do not pretend it would have avoided the crash but I do pretend it could have helped to avoid the crash.

But it is interesting to read you, and I think we are here in a situation where you read what you think you read and not necessarily what is actually written :

My comment IS :

you may now realize that instruments don’t necessarily tell what the flight control inputs are.

My comment is NOT :

you may now realize that instruments don’t necessarily tell what the aircraft is doing.

[Old Carthusian]

Of course they did - go back and read their posts. You will find numerous statements on how the yoke was more reliable than instruments. AirTren goes as far as to construct a whole castle in the air about it. Retired F4 talks about the yoke being more reliable than instruments. I would submit his memory is at fault here.
Given the way the PF reacted a yoke would have made no difference - simple as that. The cause of the accident lies in the human factors and we may never know exactly what caused the PF to act as he did. However, your preference for a yoke is an irrelevance to the cause of the accident. It would not have helped because of the circumstances of the crew on that flight.
As for your final point my comment still holds. Instruments do tell you what the flight control inputs are. That is their purpose - to give a pilot a measurable and reliable indicator of his flight control inputs.

[BOAC]

Old Carthusian - leaving aside SS/yoke arguments, I see a matter of some concern in your understanding of instrument flying. You have no 'career' information in your profile, so I have to conclude you are inexperienced in Instrument flying.

There are two glaring inaccuracies in your recent posts that I do not wish other pilots to absorb:

1) Post #69 "Yes by looking at the instruments. An input produces a certain pattern on your instruments and you can understand what your aircraft is doing" It might not and you cannot always.The instrument reflects what the aircraft is doing after the input and that may well NOT be what you intended. See AF447?

2) Post #76 "Your artificial horizon will tell you if the plane isclimbing or banking" It will not. It will, of course, certainly tell you if your nose is high or low. Perhaps you do need to re-read the AF447 report? Then tell us what PNF's EADI showed in terms of 'climb'?

Lastly, I would point out that no-one knows what PF's instruments were displaying anyway? We are (naturally) assuming they were functioning correctly - and they probably were, but we do not know.

[RetiredF4]

Old Carthusian (bolding by me)
Of course they did - go back and read their posts. You will find numerous statements on how the yoke was more reliable than instruments. AirTren goes as far as to construct a whole castle in the air about it. Retired F4 talks about the yoke being more reliable than instruments. I would submit his memory is at fault here.

That is a hard accusation of you, and a personal one. If you make such peronal accusations, you should at least quote where i did so. Lets find out whose memory is at fault.

As we exchange personal genialness, i would assume that your personal knowledge concerning flying itself seems limited, and the knowledge concerning aerodynamics and other vital aircraft dynammics is not existent.

Your analysis concerning the human factor stands well and was not doubted neither by myself nor by a lot of other posters, but it does not stand alone. There are contributing factors to any accident i´ve known so far.

To close his eyes and cry down other voices like you do here with my oppinion by disqualifying my memory places you as the first ever poster on any forum on my ignore list.

[rudderrudderrat]

Old Carthusian,
Instruments do tell you what the flight control inputs are. That is their purpose - to give a pilot a measurable and reliable indicator of his flight control inputs.
But on Airbus, the F/CTL ECAM page is not normally displayed in the cruise. A pilot would have to deliberately select that page.

[Old Carthusian]

BOAC
Of course artificial horizon will tell you if you are climbing - what do you think the gap between the horizon line and whatever symbol is used for the aircraft means? Yes it means your nose is raised but it also can be used to ascertain that the aircraft is climbing. OK here I am guilty of simplfying a bit (which is a problem for me, I value brevity and expect others to understand this.) but then so are you - it serves both purposes very adequately. What it will not tell you is your rate of climb, you need the altimeter for that and if you quoted in full you would have included my mention of the the altimeter.
The instruments are there to provide an indication of the results of your inputs. Without them you are very much guessing every flight and they are certainly more reliable than your personal impressions. As for AF447 I suspect that BEA knows pretty much what the PFs instruments were reading - they may not have chosen to release the information but they do have it. Everything released though points to a psychological reaction by the PF which was not dealt with adequately by the captain or PNF. It does not point to any problem with the aircraft. Your final point is a straw man argument - if there is no reported problem with the PFs instruments then there is no reason to impute a problem.
Retired F4
Memory - a very unreliable thing especially were flying is concerned. It's nice to be so assured about every flight you've participated in but me I cannot. I have to check and then maybe I can summon up a reliable memory. If I disqualify my memory then I also have to mistrust your memory.

[rudderrudderrat]

Old Carthusian,
Of course artificial horizon will tell you if you are climbing - what do you think the gap between the horizon line and whatever symbol is used for the aircraft means? Isn't that exactly the same error that PF also made?

[Lyman]

I do not think the PF (and the PNF + Captain) made the same basic error as Old Carthusian has made.

What did they see?

**************

Having recovered the contents of the Avionics Bay, and the boxes, will BEA report as to what the Pilots were privy to in the way of displays?

Because from the outset, and to this day, one has difficulty believing that all three pilots missed the Attitude cue, believed the Vario, and were satisfied not to push the nose down. In fact, at one point, Captain says "Climb!". Not likely a result of seeing 15NU on the panel, with a descent of 11-15 thousand fpm. The two are not compatible, and because every wag here wants to be an expert, claim the pilots have stink for think. All Three?

For that matter, what was the command pilot seeing as he took control? Did he have honest data? I have my doubts. Would a simple Back up AH have been a life saver?

The communications twixt 1 and 2 show a distinct lack of common thought. If PF's reads were total duff, why wouldn't he hand off ?

He would, and that is why I think he felt his input was reasonable.

His reads were unreliable. imo.

[AlphaZuluRomeo]

Old Carthusian,
Isn't that exactly the same error that PF also made?
Likely so... :{

[Diagnostic]

@rudderrudderrat: Yes, very likely!

@Old Carthusian:

Retired F4
Both the PF and PNF have displays with the same instrumentation on them. Your artificial horizon will tell you if the plane is climbing or banking. You derive your rate of climb (or descent) or descent from your altimeter.

BOAC
Of course artificial horizon will tell you if you are climbing - what do you think the gap between the horizon line and whatever symbol is used for the aircraft means? Yes it means your nose is raised but it also can be used to ascertain that the aircraft is climbing.

[My emboldening above]

With respect, repeating the same incorrect statement multiple times, does not ever make it correct :( Members BOAC, Retired F4, rudderrudderrat etc. are absolutely right in refuting your assertion on this point.

Please consider the other name for the artificial horizon is the attitude indicator. It is not called a climb/decend indicator - it only shows the plane's attitude (relative to the ground). The Wikipedia article on the AI seems a reasonable introduction, and I respectfully suggest that you read it - note that it correctly explains about showing the plane nose-up or nose-down (regarding pitch), and it correctly does not state that nose-up == climbing, since that would be a fallacy.

Attitude indicator - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Attitude_indicator)

To summarise:

- When you are climbing, the AI does usually show nose-up attitude.
- When the AI shows nose-up attitude, you are not necessarily climbing.
- Therefore use VSI or altimeter (not the AI), to see if you are climbing/decending.

Does this help to explain the type of replies you've been getting?

[Edited to add "usually" regarding AI indication in climb - turbulance is another factor which alters this indication, and is yet another reason why the AI cannot be relied upon to show climb/decend indication!]

[Old Carthusian]

If you had bothered to read all my posts properly you would note that I am perfectly aware of this. Selective quoting is all very well but I am guilty of abbreviating far too much and being too wooly in my terminology. However, given the phantoms that are being chased down here that can be forgiven. Actually I will strive to be a bit more precise in future - after all I can't very well criticise others if I am guilty of the same sin.

[BOAC]

Good stuff, guys (and girls?), and really more suited to the wannabee forum, and I fear we are wasting our time with this 'shoal of red herring'. Personally I am relieved to see that the Old Carthusians appear to have no connection with aviation.:mad:

[Old Carthusian]

Wrong BOAC - I do have plenty of connection but the rebuke in this case is well taken. Next time - engage brain then type.

[Diagnostic]

If you had bothered to read all my posts properly you would note that I am perfectly aware of this.
How do you know what I "bothered" to do? That's a judgement call you're not qualified to make, unless you're looking over my shoulder at what I'm reading. :)

I have read all your posts in this thread ("properly" is subjective and also depends on the clarity of your postings), and it's definitely not clear that you are aware of the correct interpretation of an AI. I don't claim to be perfect, but I was just trying to help, after believing there was a genuine misunderstanding on your part.

I am guilty of abbreviating far too much and being too wooly in my terminology.
Thanks for explaining how we got into this.

@BOAC - Agreed, I'm stopping here.

[CONF iture]

At this point, Old Carthusian, you would need to go in a flying school and ask a flight instructor to demonstrate you what the flight instruments and particularly the artificial horizon may or may not indicate regarding what the aircraft is doing.

Just to make sure, what is your experience in instrument flying ?
What is your experience in flying ?

[OK465]

You have no 'career' information in your profile, so I have to conclude you are inexperienced in Instrument flying.

Is this a "You show me yours & I'll show you mine..."?

[jcjeant]

Hi,

Lyman
Not likely a result of seeing 15NU on the panel, with a descent of 11-15 thousand fpm. The two are not compatible, and because every wag here wants to be an expert, claim the pilots have stink for think. All Three?

Collective hallucination?
You can not rule out this possibility
Read police reports about testimony regarding the UFO's
Lots conclude a collective hallucination

[Lyman]

jcjeant. Yes, a possibility of collectively focused interpretation of confusing data. I think that is what existed between the two, prior to Captain's return. A hybrid, though disagreeable "rapprochement" between LHS and RHS.

But, after Captain pops back in, the focus is on him, "What do we do?".

His is the new hope for a solution, and unfortunately, he does not grok the panel(s), nor does he see (relax....) the SS. There is virtually no chance he saw, believed, and acted upon two divergent readings from two separate instruments. His was the 'stuckness' one feels when out of options, let alone decent data.

It takes a leap of uncommon collective hysteria to believe these were three stooges. They were not, they were baffled by a situation that had gotten so far ahead of them, there was not sufficient time to unwind it, and try options.

So, back to square one: 2:09:30. A Flight computer commanding a dive, airspeed reads that were duff from either ICE or Turbulence, and a crew who were not "following" the bird as it lost its way.......

In the absence of explanation for the autoflight command to dive (Zipper), a postulate. The a/c malfunctioned, and the pilots were handed back an a/c that was in UPSET, without awareness of the level of trouble they were in.

Nothing of any sort by way of casting aspersions. This is unaddressed by BEA. How long will this remain the case?

[CONF iture]

As far as SS commanded proportional 'G' and the THS, what was the 'G' indication in the Flight Data block during the full nose down SS command prior to manual re-trim?
At that time we were well established in a 15000ft/min descent, stable, no bank, a G meter would have probably indicated 1G.

With the SS full forward, I would expect the elevators to be full leading edge up for a simulator full nose down command, and be displayed as such on the SD.
Then we both agree that both elevators should show a full down deflection.
If it was not the case, it would be a major MAJOR concern ...

One then would in general expect the nose of the simulator to follow this command. Why it didn't in the 330 and evidently did in the 320 is what's at issue.
My personal answer would be that the 12 deg NU THS position influence for the 330 simulation had much more impact than the full ND elevators position.

[TTex600]

Instruments are more reliable than human perceptions .

This statement is correct, but it means absolutely nothing in the context of this discussion. The original problem with AF447, as far as we know, was UAS. Unreliable Air Speed. That is an instrumentation/indication anomaly. An incorrect instrument. In this case, the less reliable human was forced to deal with a computerized system unable to function as designed. In my opinion, the human is the only intelligent link in the chain, but the only link influenced by perceptions. The instruments and computers are not influenced by perceptions, but they are also unable to function in the absence of proper data.

Overall, I think your statement indicates an lack of awareness of the situation the pilots faced. In the interest of preventing further UAS instigated deaths, why don't we focus on the reasons the human perceptions were incorrect? In fact, they were operating/flying a machine that uses computed info for both flight indications and flight control. We HAVE to focus on the human to machine interface instead of defending the machine at all costs. Anything less is a disservice to the dead.

[CONF iture]

Lyman,
I can well understand your last post and I do share it.

[DozyWannabe]

So, back to square one: 2:09:30. A Flight computer commanding a dive

Again with the making stuff up. Where do you come up with this, and do you find misdirection that enjoyable?

And airtren, could you be more specific with the "manufacturer problems", because outside of the pitot tubes, I don't see any.

Silent running re-engaged...

[BOAC]

Is this a "You show me yours & I'll show you mine..."? - actually no, but based on the apparent complete lack of understanding of aircraft performance and instrumentation. Don't tell me you cannot see it?

Incidentally, all are welcome to see 'mine' - just a simple click.:)

[Lyman]

Able to raise the dead with a mere click, eh? Erm, misdirection? I like to think of it as focus. There are anomalies present (and ignored) since day one. Why not cease the misdirection toward the messenger, and address the problems? "Nothing to see here, merely a poor graphing result....."

Full of conclusions re: defense, yet an obvious sleight of mouse when confronted with exculpatory?

If one owns the "correct" conclusions, one is credible? If one merely proposes, or asks a question, "off the reservation," one is to be ignored?

Nice try, Lazarus. :D

[Organfreak]

Yep BOAC, it is apparent even to me, re who knows WTF they're talking about and who doesn't! (I've learned a tremendous amount about flying the big jets by simply following these threads, thanks to all.)

I think that, given the complete lack of solid truth about this accident, toady we have gotten closer to The Truth in both threads (whatever that may be). :8
Clearly, it is much more complicated than either incompetent pilots versus evil software. Those firmly on one side or the other are talking out their, uh, patooties.

[A side note, if anyone is interested. I'm getting mysterious private messages from unknown parties that question me about misrepresenting who I really am. I don't know what the problem is, but I've apparently touched some nerves out there. It's rather unsettling to get these creepy accusations. Maybe they mistake my intelligence for some sort of sekrit piloting knowledge. :yuk:]

[Lyman]

Organfreak. It is the constant annoying paranoid PMs that I receive that have caused me to molt. It comes with the terror-tory....

This subrosa attempt at moderating is unsettling, but harmless. It speaks to the fear some have of probing questions.

CONFiture. Thank you, Sir.

[Organfreak]

Thanks for the reassurance, Lyman. Good to know.
I should have also mentioned that I also received some private thanx from more than one real pilot, for defending their posts. That tells me that I'm not (entirely) talking through my hat. And now, back to our regularly-scheduled tomfoolery. :ugh:

[BOAC]

A side note, if anyone is interested. - yes, I am. Are they suggesting you do not, in fact, play the jazz Hammond organ?

There is a slight problem here on PPRune in that the content of Private Messages should be so, but I don't think there is any etiquette preventing you from telling us who is sending them? Perhaps then they could speak out here with their doubts rather than filling your inbox.

We might even be able to help with the 'unknown parties':)

[Lyman]

Off the plot? Singing from different Hymnals? Who are these Shepherds of group think?

[DozyWannabe]

Coming back from the "dead" (I prefer resting ;) ) to point out that Lyman has received no PMs whatsoever from me for a considerable time. Organfreak has received none from me full stop.

Old Carthusian has oversimplified to the point of making an incorrect assertion, but that doesn't invalidate what he's saying. The problem is, so has Lyman - "Commanding a dive" is a completely incorrect description for what autoflight was doing, which was attempting to hold altitude in turbulent conditions.

Organfreak, let's be clear here - I'm not saying that the pilots were incompetent and I'm not saying the software or design is perfect. I'm saying that this incident appears to be caused by a systemic problem when it comes to training, as well as a significant safety blind spot when it comes to how AF was rostering flights once the UAS problem was known and highlighted. I get annoyed with the yoke/sidestick argument because it is a *distraction* - there is no quantitative evidence to suggest it would have made a difference, and what we have is a few posters (not all of whom are pilots) with an axe to grind trying to make the argument all about them and their prejudice.

TTex600, air data has been processed on its way to the gauges for as long as gauges have been around. Whether the processing was mechanical, electric analogue or digital, it has been done - the only way to provide a direct translation would be to blast the pilot in the face with air channeled from the outside. :) All the indications so far indicate that the standby (ISIS) panel was working for everything except speed (and the speed came back later in the sequence). You know you can see it fairly clearly from either seat. Even if the RHS lost all air data (airspeed and altitude), he'd still have had the attitude indicator and should have been able to read the standby. If he didn't feel confident with the information he had, the correct thing to do would have been to hand over control.

[Organfreak]

BOAC done wrote:
Are they suggesting you do not, in fact, play the jazz Hammond organ?

There is a slight problem here on PPRuNe in that the content of Private Messages should be so, but I don't think there is any etiquette preventing you from telling us who is sending them? Perhaps then they could speak out here with their doubts rather than filling your inbox.

We might even be able to help with the 'unknown parties'

Thanks you so much, sir, for your interest. (I don't expect much interplay from you-all, since I have no standing as a pilot.)

First, that's the oddest part: they haven't questioned my status as a jazz organ expert (if you can play good jazz organ at speed, you can keep a large jet flying too, I always say, ha ha), but rather, the weirdest series of msgs. was insisting that I was hiding my identity and it was time to reveal "who [I] really am." I also hesitated to post any of this publicly, but that user's nym is KBPsen. I looked at one or two of his/her posts, and saw that they also had clashed with Dozy, which was even more puzzling to me. I finally sent my real name, location, and website to this person, as I have nothing to hide, and those messages stopped.
Lately I had a mysterious note from a "The Barber" warning me that someone was impersonating me here(!!!) ME??? WHY? Creepy that he had my "official" email address rather than the one I use for this forum.
Sorry to others for this diversion. :\

[Organfreak]

Organfreak, let's be clear here - I'm not saying that the pilots were incompetent and I'm not saying the software or design is perfect. I'm saying that this incident appears to be caused by a systemic problem when it comes to training, as well as a significant safety blind spot when it comes to how AF was rostering flights once the UAS problem was known and highlighted.

I do appreciate your attempt to clarify your views, and that gives me the opportunity to apologize if I was harsh with you. I don't disagree with any of the above, except your apparent view that the accident had only one cause. I can never keep my mouth shut when I see over-simplification (IMO). Clearly, there was a training problem, and horrible/non-existent CRM.

I get annoyed with the yoke/sidestick argument because it is a *distraction* - there is no quantitative evidence to suggest it would have made a difference, and what we have is a few posters (not all of whom are pilots) with an axe to grind trying to make the argument all about them and their prejudice.

Nor is there any evidence whatsoever that it would not have helped in this situation. YOU CAN'T KNOW THAT! Do I get to take this point? :) I repeat an earlier utterance: As a SLF, I want my plane to be as foolproof as humanly possible! No-one is suggesting that, based on one accident, SSs should be ripped out and replaced with yokes, fer cryin' out loud.

[DozyWannabe]

I do appreciate your attempt to clarify your views, and that gives me the opportunity to apologize if I was harsh with you.

No problem, accepted.

I don't disagree with any of the above, except your apparent view that the accident had only one cause.

I was kind of hoping that the word "systemic" would imply that I think the causes are myriad in number as opposed to just one, which is indeed the case.

Nor is there any evidence whatsoever that it would not have helped in this situation. YOU CAN'T KNOW THAT!

Let's be clear here - I'm saying that based on the evidence we can't know one way or the other and it's a purely speculative exercise. I think you'll find that it's the vocally pro-yoke guys who are insisting that it would have made all the difference.

No-one is suggesting that, based on one accident, SSs should be ripped out and replaced with yokes, fer cryin' out loud.

You'd be surprised, and that's all I'll say.

As for wanting aircraft to be foolproof, they've come a long way over the last 50 years and it has proved to be a mixed blessing in a few ways, because as aircraft have become more reliable, a serious systems failure can become more of a psychological shock to the pilot when it does occur. The B757, for example, had an unprecedented safety record for a short to medium-haul narrowbody until the mid-90s, when two minor maintenance errors led to loss-of-control and a crash. This is why I'm inclined to focus on improvements in training, because ultimately even with improvements in automation and technical reliability the pilot is the last link in the chain and must be prepared.

[Organfreak]

BOAC said:
We might even be able to help with the 'unknown parties'

OK, in further developments, the 'Barber' person who's been messaging me apparently does mean well towards me and his warning was, I guess, friendly. The person who put the weirdness up HIS nose (by email) turns out to be a former user here who went by the handle "airfoilmod." I found a brief discussion, in the archives, of his disappearance from here. Funnily enough, BOAC was involved in that discussion. I guess I'm not concerned any more about proving my bonafides: I have no bonafides! And I have said so! I guess THAT is what some people cannot wrap their minds around. :O

[Organfreak]

Dozy wrote:
As for wanting aircraft to be foolproof, they've come a long way over the last 50 years and it has proved to be a mixed blessing in a few ways, because as aircraft have become more reliable, a serious systems failure can become more of a psychological shock to the pilot when it does occur.

I couldn't agree more! Have a cigar!
:}

[BOAC]

I seem to recall that "airfoilmod"' disappeared' at his/her own request some time ago.

Funny old world. Brush it off. We are happy you are here. If you are 'hiding', you are not alone.:)

[TTex600]

Dozy, the ISIS is just a mini EFIS, supplied with data from the same computers and symbol generators as everything else the pilots could see. Why do you keep mis-characterizing my postings?

[DozyWannabe]

I'm pretty sure that the data source for ISIS is selectable, just as the standby instruments were in the steam gauge days. You seem to be concerned that there is a computer involved - why? The computer is not generating the data for the EFIS, it is merely translating it for display.

In the case of my experience, the ADC on my side was failed, and the ISIS was taking it's information from the Captain's ADC, which was why I could read it.

[Organfreak]

Thanks, BOAC, you are a Mensch. Let me ride on your next flight.
I may be one of the few here who is NOT hiding! End of thread excursion.

[BOAC]

Thank you, freaky.

Now, as the man says, back on track. While I can perhaps understand the change of 'Air Data', I cannot remember if, in all the SS stirring that seems to have taken place here, anyone clearly told us why the PF's 'ATT/HDG' was changed to 'FO on 3' where I think it stayed and what that would have done in the circumstances?

[OK465]

BOAC: I think ATPL & 'retired' will thwart most Nigerian bank scam artists. :)

Then we both agree that both elevators should show a full down deflection.

CONF: I generally agree with most of what you post also (not everything of course, being a pilot :)). You can tell an actual 330 pilot (but as the old joke goes, you can't tell him much). I appreciate your general objective outlook & knowledge.

On the technical side, if the Flight Data block did not display a green or amber 0.XX 'G' indication (something less than 1 'G') and result in nose down movement as one would expect with a full nose down SS command, then at least as far as the simulation, overall pitch authority appears to be lacking at this point. If full nose down SS did not move the nose down, I would also make the assumption that neutral SS independent of pilot input would not have resulted in nose down? Can the gross effect on aero AOA be indirectly inferred from the lack of change in pitch and the same lack of change in the Flight Data displayed (or in the case of 1 'G' probably not displayed) inertial load factor?

I think objective discussions of Phase 3, both aircraft and human factors, & simulation overall are not unreasonable discussion items as references to both are contained in Interim #3 (somewhat extensive when it comes to Phase 3), although, as others, even with what was reported available I subjectively feel Phase 3 should never have been entered. Aircraft handling comparisons borne of 320 or other aircraft experience are interesting at least, possibly valid at best, but unsubstantiated to varying degrees.

(These internet discussions of accidents provide certain educational value and a dubious 'entertainment' experience that obviously does not in anyway substitute for an in-depth accident investigation being conducted by true experts, nor diminish the tragedy of the whole thing.)

There are posters (not you) who 'define' themselves into unassailable positions of no practical value. There's a lot to be learned here I feel, but certainly not as much as is to be learned from the actual investigation. Everyone here, bona fides or not, is I would think entitled to a spirited aviation discussion. Discriminating is the watch word.

(BTW, many standard training simulators (sim only feature) incorporate the capability to selectively artificially monitor, for example, flight data package AOA & beta or other selectable parameters where normally VOR DME 1 & 2 would be displayed on the ND. This can at times be educational also, at least to a 'sim-geek'.) :)


EDIT: For TTex, even with triple ADR failure and multiple electrical failures you will still have an ISIS.

[airtren]

…. Personally I am relieved to see that the Old Carthusians appear to have no connection with aviation.

Based on permanent distortions, wrong associations of terms, and misrepresentation of technical terms of text of my posts, as well as simply wrong technical statements, your conclusion seem to apply/extend to engineering as well


……. I am guilty of abbreviating far too much and being too wooly in my terminology….
I assume based on the posts that drove to this one, that it is not necessary to ask the stop of the twisting, distorting, and misrepresenting of the text of my posts.



Japan is also known as the “land of the rising Sun”, so there may be a language interpretation and translation element involved, as well as the possible difference between the meaning of certain words in regular language versus technical language. While that’s an additional excuse, it is also an additional reason to be more careful, particularly in fields that are not fully familiar.

[HazelNuts39]

anyone clearly told us why the PF's 'ATT/HDG' was changed to 'FO on 3' where I think it stayedSome 90 secs later the CAPT PFD was switched to ADR3 and ATT/HDG3 and the FO back on 2.

[Lyman]

Is this some evidence of looking for some clues? Some trustworthy ones?

Must have been some ride.

[airtren]

And airtren, could you be more specific with the "manufacturer problems", because outside of the pitot tubes, I don't see any.


I will gladly answer....

But, you have some questions or invitations to answer in your input queue, from my posts, which you have not answered yet.

Please process that, before I add another post of mine to that queue.


... and I'm not saying the software or design is perfect.

Text marked in bold indicate a contradiction from one post to another…. so which one is be taken as TRUE?


I get annoyed with the yoke/sidestick argument because it is a *distraction* - there is no quantitative evidence to suggest it would have made a difference, and what we have is a few posters (not all of whom are pilots) with an axe to grind trying to make the argument all about them and their prejudice.


You’ve skipped a direct invitation of answering on “the lack in the cockpit of visual contact with the SS, or the actions on SS”, which may have helped you get out of the monotony of your “yoke/ss argument” annoyance.

But maybe that annoyance is welcome, as it is the feed to posting the obsessive instance of one of the "anti-Airbus brigade", or "axe to grind.. with Airbus", or something to that effect....



As for wanting aircraft to be foolproof, they've come a long way over the last 50 years and it has proved to be a mixed blessing in a few ways, because as aircraft have become more reliable, a serious systems failure can become more of a psychological shock to the pilot when it does occur. …. This is why I'm inclined to focus on improvements in training, because ultimately even with improvements in automation and technical reliability the pilot is the last link in the chain and must be prepared.

Any system failure or system weakness exposed by an accident, which otherwise would not be known, MUST continue to be the focus of fixing, or being eliminated, as to bring that airplane back in line with its expected safety standard behavior before this exposure.

[chrisN]

Who or what did the switching? (No agenda here, just interested/learning.)

Chris N (who is who he says he is, and has not misrepresented his experience or qualifications – but has not previously mentioned a few years past experience also in a major aero engine company, because it is not particularly relevant or illuminating in this context.)

[lomapaseo]

as to bring that airplane back in line with its expected safety standard behavior.

You got me here :confused:

What exactly is out of line with the aircraft and its expected standard of safety?

Is it a design fault that was missed in certification?

Is it a manufacturing fault that was missed in Quality Control?

Is it a wear out mode fault that was missed in maintenance?


no doubt there are one or two items in the pot of causal factors, but unless you delinate them it will sound like just another bash the product claim just because it sounds good..

[airtren]

Organfreak,

I appreciate your recent posts, and your "green" note.

I find it hilarious that DozyW*e replied on this note, as this type of questioning/accusation is on his resume on this forum... which I've taken as a device in his tactical arsenal, in pursuing his self assumed mission of public opinion control regarding AF447.



A side note, if anyone is interested. I'm getting mysterious private messages from unknown parties that question me about misrepresenting who I really am.

... Organfreak has received none from me full stop.

[DozyWannabe]

Well dang, heaven forbid I make it clear that I wouldn't stoop to giving people grief via PMs, given our disagreement up until that point. For what it's worth, I was PM'ed by the same person some time ago stating that you and Lyman (then bearfoil) were the same person. If this turns out to be false then you have my apology.

[airtren]

You got me here :confused:


as to bring that airplane back in line with its expected safety standard behavior. What exactly is out of line with the aircraft and its expected standard of safety?

Is it a design fault that was missed in certification?

Is it a manufacturing fault that was missed in Quality Control?

Is it a wear out mode fault that was missed in maintenance?


no doubt there are one or two items in the pot of causal factors, but unless you delinate them it will sound like just another bash the product claim just because it sounds good..

You've got me too here for a moment....

I was referring in general to an airplane involved in an accident - you've "quoted" the last part of it - but I agree the wording could be clearer in that respect, so I edited, to make it clearer.

If you have a problem with it in its edited form, please let me know.

[DozyWannabe]

Text marked in bold indicate a contradiction from one post to another…. so which one is be taken as TRUE?

You show me a post where I said the aircraft and systems were perfect. At the risk of sounding juvenile, I bet you can't.

You’ve skipped a direct invitation of answering on “the lack in the cockpit of visual contact with the SS, or the actions on SS”, which may have helped you get out of the monotony of your “yoke/ss argument” annoyance.

Not at all, I've stated outright that I don't think it's as big a deal as some are making it out to be, and I'll give you some reasons if you like:


More than 30 UAS incidents in the A330/340 passed without incident. If not being able to see/feel the other pilot's sidestick was a safety concern, more of them would have crashed.
At least two aircraft equipped with interconnected yokes had a similar LOC/stall/crash event, one of which shows evidence that the F/O didn't like what the Captain was doing and did not overrule him.
The sidestick design was approved by one of the most respected test pilots and safety gurus of his day.


But maybe that annoyance is welcome, as it is the feed to posting the obsessive instance of one of the "anti-Airbus brigade", or "axe to grind.. with Airbus", or something to that effect....

Well, when one has been here 9 years and has seen the same people make the same arguments over and over again, it's difficult to resist noticing and commenting on the pattern.

Any system failure or system weakness exposed by an accident, which otherwise would not be known, MUST continue to be the focus of fixing, or being eliminated, as to bring that airplane back in line with its expected safety standard behavior before this exposure.

I hope I've answered your questions, so as such I see no systems weakness in the design other than the pitot tubes. Perhaps you'd be kind enough to give me the benefit of your opinion on the matter.

[TTex600]

EDIT: For TTex, even with triple ADR failure and multiple electrical failures you will still have an ISIS.

Thanks, my FCOM/AOM shows ADIRU input into the ISIS, but I'll take your word that it derives it's own attitude and airdata information.

Be that as it may, my point is still unchanged. Everything on the panel is computer generated. The only thing I can count on in the Airbus is the horizon out the windscreen.

If I was scared of the technology, I'd never go to work or I would change employers and go back to flying a DC9. However, I want to understand the technology.

On a related subject, I have been in a 319 that failed to respond to SS input asking for nose down. I was maneuvering, avoiding one buildup and flew into another which was a substantial updraft. I had already pitched for green dot trying to climb above the first buildup and when I flew into the second updraft the aircraft failed to respond to my nose down, fwd, SS input for a couple of seconds. I assumed at the time that the updraft caused a "g" loading that fooled the ELAC. The buildup was small and we flew out of it in a few short seconds. PM me if you have any input.

[TTex600]

FWIW, Dozy once sent me a PM and was quite the gentlemen.

[Organfreak]

Thanks, airtren. Though it's obvious that I cannot fly (with or without an airplane), I assume that I'm getting a bit of respect here because I can think clearly and can easily understand the issues raised. /ego trumpeting

Just for the record, your honours, I didn't accuse Doozy of sending me the creepy PMs, nor would I, chiefly because they were from a different registered member here, who, oddly, has never seen fit to post in these AF threads, that I can remember.

Anywho, back to one of the matters at hand. DW, you posted, among millions of other things,

More than 30 UAS incidents in the A330/340 passed without incident. If not being able to see/feel the other pilot's sidestick was a safety concern, more of them would have crashed.
At least two aircraft equipped with interconnected yokes had a similar LOC/stall/crash event, one of which shows evidence that the F/O didn't like what the Captain was doing and did not overrule him.
The sidestick design was approved by one of the most respected test pilots and safety gurus of his day.

With all due respect, you're still missing the fine distinction that is being made here. These "fine gurus" forgot to anticipate one big possibility, namely, the eventuality that the PF might not know what the hell he's doing.
That may be the difference in why those 37 other UAS ABs did not crash.

Those of us who harp on this are not trying to destroy Airbus; it is rather an intellectual curiosity that wishes to understand ALL of the "whys" involved, not just one big, simple black-and-white picture.

I had better subside before I write myself into a "deep stall."

[Diagnostic]

@DozyWannabe:

While I appreciate your posts and I learn from your comments, I cannot let the following go without commenting:

More than 30 UAS incidents in the A330/340 passed without incident.
I respectfully suggest that saying "without incident" is an over-simplification, which may be unhelpful in diverting attention away from the (IMHO very relevant) information about what happened on previous UAS incidents where enough info was gathered for BEA investigation.

Check Interim report 2, PDF page 51 onwards, and you'll see these points. Note that only 13 UAS incidents had sufficient data available for the BEA to do a sensible review of them. Sure, none of the other flights crashed, but several were not handled according to the QRH, not all of them went into Alt* law meaning that subsequent actions cannot sensibly be compared to AF447, etc. etc.

My view is that where the detailed data is available to allow a reasonable analysis, there were systemic issues in UAS handling shown in that data for several other flights (e.g. failing to recognise that UAS had occcurred, not correctly disconnecting the FD, incorrectly re-connecting the AP during the UAS event etc. etc.). In other words, some holes in the swiss cheese did line-up in other UAS incidents, but just not all of the holes as on AF447.

The evidence is clear in that section of Interim report 2, that (in the 13 events where sensible analysis could be done) incorrect & potentially dangerous handling of some other UAS events has occurred. IMHO, that is not consistent with the statement of "without incident", unless you mean "without crashing", which is not a great measurement :)

If not being able to see/feel the other pilot's sidestick was a safety concern, more of them would have crashed
Due to the points above, the actual sample size of comparable UAS incidents is so small that, given the (thankfully) low rate of crashes anyway, I believe the sample size is too small to support your assertion regarding whether more of them "would have crashed" or not. I'm not asking you to agree with me :)

[airtren]

.
One then would in general expect the nose of the simulator to follow this command. Why it didn't in the 330 and evidently did in the 320 is what's at issue.

My personal answer would be that the 12 deg NU THS position influence for the 330 simulation had much more impact than the full ND elevators position.

This caught my attention, as it seems related to the points made during the discussion on the #6 thread, about the THS versus elevators during the AF447 stall.

[jcjeant]

Hi,

DW
I see no systems weakness in the design other than the pitot tubesAnd this is the biggest weakness you can found on the modern planes who are using computers and automated flight systems
This is one of the most important source of data for the automation system
Another failure of testing and certification process .... and so another invite to disaster
For a Curtiss Jenny .. a pitot tube clogged was not a very important problem ... for a Airbus or other brand using automation .. it's a crucial data loss

[DozyWannabe]

However, I want to understand the technology.

Excellent - I'll help if I can (and thanks for the previous post).

Be that as it may, my point is still unchanged. Everything on the panel is computer generated. The only thing I can count on in the Airbus is the horizon out the windscreen.

OK, so why do you feel that to be the case?

For starters, I'll identify myself as a software engineer (which is a fancy way of saying computer programmer trained in traditional engineering discipline). I've said a lot of this before, but in this case I'll try to summarise as briefly as I can. Please forgive me if I'm going too much back to basics - the last thing I want to do is sound like I'm teaching people to suck eggs.

In general, the computer systems that make their way into aircraft are a world away from the way that they have been portrayed in popular culture over the years, and from the systems you and I use to post on this board, for example. The analogy I like to use is that modern home computers are like a highly-tuned racing engine, and the computers in your aircraft are more akin to an old pick-up truck engine, or possibly a marine diesel or something. Breaking that analogy down, home computers are designed with the latest technology in the hardware, and software that is designed to maximise use of the hardware available (with all the complexity that implies). It is therefore accepted that a breakdown or crash is expected to happen relatively frequently and also that the system itself will be replaced on a relatively short timescale. Industrial and embedded systems (including the realtime systems used in aircraft) use obsolete and trusted hardware (the processors in the A320 were obsolete even by 1988 standards), and the software testing process and inbuilt redundancy is several orders of magnitude more involved than in any other discipline. It is also designed to be very simple in design - almost comically so to a programmer - where real-time systems stop being funny is the level of smarts required to build machines that can perform complex tasks using only these simple, exhaustively tested sets of instructions. It is specifically designed to run for years, if not decades without incurring a fault - and if that wasn't enough, there's an implementation of the same specification running on the other computer with entirely different code, and the two implementations are constantly checked against each other.

The upshot of which was that in order to certify the A320 and her sisters, the engineers had to prove that each component and program involved was as reliable, if not more so, than the steam-gauge equivalent. If you think about it practically, the millions of flights performed by FBW Airbuses since their introduction - without a single serious incident attributed to the flight control software - is nothing short of remarkable if you haven't been drilled on just how strict the development process was, and still pretty impressive even if you have.

[EDIT : One of the reasons I dislike the "HAL" analogy is because HAL was a fictitious construct to allow a storyteller to advance his plot - if I were to use Captain Sullivan from "The High And The Mighty" to characterise pilots, I would be quite rightly chastised. It's better to think of the A320 systems as a whole bunch of "HAL"s that are constantly checking each other, are capable of shutting down a "HAL" who is malfunctioning (and, importantly, take over his functions until they land), and if the active "HAL"s can't work it out, Dave gets to do whatever he needs to get them home safe. ]

Going down even further, it's worth noting that the ADIRU units themselves are nothing more than translation units. They get a simple set of inputs in from the air data and inertial sensors and translate them into a format that is used by the flight control computers and the EFIS. All the EFIS does is render that information into a visual display - nothing more, nothing less. It can't change the values, it does no summing or checking of the values (that's done by the flight control computers, which check the values against each other). In short, all the data path from the sensors through the ADIRUs to the EFIS does is mimic the old-fashioned mechanical or electro-mechanical data path used in the steam gauges. Involve the FDs and things get a little more complicated, as the flight computers get to input to the EFIS as well, but one can't change the other.

Basically, if you've got a good set of inputs from the sensors, then there's no reason to think that what you're seeing on the EFIS is not the 100% unvarnished truth. The system is also designed to degrade gracefully so that, for example, if the pitot tubes are blocked, you will lose only airspeed information - all the rest of it should remain in place. A situation like this is "abnormal" in the sense of the system as a whole only - in terms of the individual components this has been designed for and the system is designed and programmed to compensate. This is significantly different from home computers where an error in one task can have a detrimental effect on the others.

I hope that helps and if you've got any questions please feel free to ask.

I had already pitched for green dot trying to climb above the first buildup and when I flew into the second updraft the aircraft failed to respond to my nose down, fwd, SS input for a couple of seconds. I assumed at the time that the updraft caused a "g" loading that fooled the ELAC. The buildup was small and we flew out of it in a few short seconds.

If the updraft was strong enough to significantly alter the "G" loading then the ELAC was not "fooled", as such - it was doing what it was supposed to. In such circumstances you've got two options - either give the sidestick a little more down-pitch to counter the G-loading from the updraft or (probably more sensible, as you did) ride it out until the updraft passes. You clearly knew enough about the aircraft and how it works to work that out.

That said, if I recall correctly the system should allow for maneouvres up to 2.5G (just shy of the structural limit of the aircraft when sustained), so I suspect there was a little more to it than that - as to what that "little more" was, your guess is as good as mine. :)

@Organfreak - just to reassure you, I wasn't accusing you of anything. I just wanted to make sure people knew that I wasn't harassing you outside of the thread, given that we've been crossing swords recently.

@Diagnostic - I was, perhaps incorrectly, using "without incident" as a euphemism for "not crashing". You're also right on the other point - my stats and engineering professors would kill me for using such a small data sample to make my case, but unfortunately it's all we've got.

@jcjeant - Losing one pitot tube should no longer be a problem for modern airliners. What we had in this case (which hopefully by now has been remedied) was a situation where they were routinely losing *all three*. That this could happen with a design that nevertheless passed certification requirements is extremely worrying, but that's a different subject.

[lomapaseo]

airtren

I was referring in general to an airplane involved in an accident - you've "quoted" the last part of it - but I agree the wording could be clearer in that respect, so I edited, to make it clearer.

If you have a problem with it in its edited form, please let me know.

and your edit

Any system failure or system weakness exposed by an accident, which otherwise would not be known, MUST continue to be the focus of fixing, or being eliminated, as to bring that airplane back in line with its expected safety standard behavior before this exposure

agree:ok:

regardless of who's at fault, he who breaks the crockery must pick up the pieces

That's the basis of continued airworthiness

in other words no manufacturer or operator is going to allow his product to continue to injure people, just because they feel it's the other guys fault.

The issue for some time has been, what has been done, what will be done and when,

I'm just not impressed with pages and pages of discussion about the future actions needed from folks that have no dog in this arena.

[Organfreak]

I'm just not impressed with pages and pages of discussion about the future actions needed from folks that have no dog in this arena.

I have no dog or cat in that rodeo, but I might have my a** in your Airbus!

(So, it matters to everyone who is curious.)

Rethpecthfully Thubmitted,
Etc., etc., ret.

[jcjeant]

Hi,

DW
(which hopefully by now has been remedied) Technically seem's nothing is changed ..
No new certifications or new tests
I think it's only some changes .. paper work and some supplementary training
Pitot tubes keep their weakness .. and pilots must leave with it
No good
The work must be adapted to the workers and not the contrary (Taylor rule)
BTW .. it was many incidents with the Pitot tubes .. and all know that incidents are always the precursor of accidents (it's always a precursor and if no "crackstopper" is put in place for stop the failure .. you have the accident)
Concord had 57 incidents with tires ... (precursor) and in the fatal accident .. the tire was involved
Nothing mysterious

[lomapaseo]

Organfreak

I have no dog or cat in that rodeo, but I might have my a** in your Airbus!

(So, it matters to everyone who is curious.)

Rethpecthfully Thubmitted,
Etc., etc., ret.

Curiousity is one thing, but telling the experts how to do it or that their fix won't work is quite another

When it comes to managing safety on an existing product, one does not go back to the original design and tinker with that as it will take far more time to wring it all out since you will have likely introduced new unknowns.

You are more likely to get far faster results by tinkering with minimization and redundancy and upgraded manuals and training.

[Pali]

Sorry folks for being interrupted by a frequent passenger, but regardless of this endless argument, is there any lesson for pro pilots from this tragedy and discussions? Is there any agreement between pilots on what to do with more care and skill to prevent such a horrible scenario? Is there anything what changed minds of pilots since CVR and FDR of AF447 have been found?
Thank you.

[BOAC]

Who or what did the switching? - PNF by my reading of the report. (PS Liked the comments in brackets:))

Pali - as I said many moons ago on another of these threads, I hope so. I hope the lesson that we still need basic flying skills gets home to those who need it and that those who fly Airbus - or any other fly-by-wire aircraft - realise that 'flying' it might one day not be a simple 'walk in the park' and that it can kill you and your passengers just like any other piece of flying metal.

[chrisN]

BOAC, thanks. CN

[Pali]

Pali - as I said many moons ago on another of these threads, I hope so. I hope the lesson that we still need basic flying skills gets home to those who need it and that those who fly Airbus - or any other fly-by-wire aircraft - realise that 'flying' it might one day not be a simple 'walk in the park' and that it can kill you and your passengers just like any other piece of flying metal.

Thank you, I hope with you. :ok:

[airtren]

For starters, I'll identify myself as a software engineer (which is a fancy way of saying computer programmer trained in traditional engineering discipline).
Software engineer is quite generic nowadays, doesn't tell much. It's like saying I am a pilot. Without more info... doesn't say much. The type of programming, or software, the programming languages, and depending on that, the processors one has programmed for, would be more descriptive...

.... The analogy I like to use is that modern home computers are like a highly-tuned racing engine, and the computers in your aircraft are more akin to an old pick-up truck engine, or possibly a marine diesel or something. I will make some additions, and a different analogy - I don't know what "highly-tuned racing engine" or "home computer" you had in mind, as I particularly don't think that a "highly-tuned racing engine" fits the home computer reality.

A.
Using motor vehicles for the analogy, I would say a home computer is rather like a small size sedan, you can use it at many basic things around the home for the family. Depending on how recent it is, it may have a few more horse power than a previous instance of the model, and a bit more room in the trunk, or more comfortable seats.

The car has many generic components that are used in an entire family of cars.

The central piece that make the home computer usable, is the operating system - the OS - which is a very special set of software programs which brings usability to the hardware. The programs of this set are completely different from the general software used on the computer. Some of these software programs, and their modules, are extremely specialized for one or a few tasks. A very critical subset of modules is grouped into what may be called "kernel", or "core", which is always active on the home computer, and any problems with it result in a crash of the entire computer, requiring a complete reboot. The operating system is separated from the rest of the software through sort of a "virtual fence", to ensure the unaltered functionality, reliability, and security. The OS on a home computer is of a "general use OS" category. The rest of the software on the computer is applications software, and is more general in nature, in terms of how the software is written, and computer resources they have access to. Applications interact with the OS through an interface, called Application Programming Interface (abbreviated API), which allows a controlled passing through the "virtual fence". In general, each application software may provide certain specific functions, or functionality to the users. There may be several applications that provide the same functions, for instance, one may have several Internet browsers, or several text processing applications installed on a home computer - for instance Notepad, Wordpad, and MS Word. The separation, or the "virtual fence" between the operating system and applications allow installing new applications, or new versions of existing applications, or removing applications without affecting the operating system, or the other applications. Furthermore, the malfunction of one application is different than the malfunction of the OS. While the malfunction of the OS can result in a computer crash, affecting the entire computer, the malfunction of an application results in an application crash, which affects only that application and immediate use at the time of its malfunction, and does NOT affect the rest of the computer (rest of applications and OS). After such an application crash, one can just restart, or activate again the application. Each application has a user interface, which allows a direct interaction with the user. An application may process different data, depending on its type, and the user's needs. For instance a Spread Sheet program may process financial data for a user, or the small shop inventory for another user. The "user interface" of the application is using OS functions - through the API - for accessing specific hardware components tasked for interfacing with the user, like keyboard, mouse (input), and screen (output). The application may use the OS "file system" functions - through the API - for storing or retrieving data from a 'hard disk", "external disk", or "memory card", a "CD", or "DVD". Furthermore, the application may use the OS "data networking functions" - through the API - for interacting over the data network - Internet - with other applications - for instance a browser would be in this category. Some applications are present but run seldom, or not run at all.

B.
The computers used in a modern a/c are more like a very specialized very rugged type of vehicle used by some police/fire/rescue departments for intervention in very special and adverse conditions, for instance mountain trail conditions. They could not be used for a family's daily errands, or for going to a pic-nic, or vacation. The extreme reliability requirements translate into the use of components that are well known, well understood, verified by time, use, and abuse, but also manufactured for functioning at different specs than the generic ones - for instance temperature, pressure, humidity, radio interference, etc... .

The software running on these computers is in the "real-time", or "critical response-time" category, while it is also in the "dedicated" category, as opposed to "general use". The operating system is very specialized, and performs only a few tasks that are necessary for the functions of that computer. It can be regarded as a small subset of a home computer operating system. As response time is critical, the software is supposed to be highly efficient, and therefore is written following very specific requirements in terms of using the computer resources, or processor mechanisms - this makes sure that time consuming ways of using/programming the processor are excluded. It is likely that the computer would have only one or a few application programs installed. An application provides a very specific function, or small set of functions. It starts when the computer is turned ON, and runs permanently, as long as the computer is ON. It does not have a user interface, it always accepts as input, processes, and provides as output the same type of data. The line of separation between the operating system and applications is totally blurred or not existent - installing a new version of the the application if ever it is done by installing one new block of software, which contains the OS. A malfunction of the application is unacceptable, but if happens, it brings the entire computer down. A computer crash is in general "unacceptable".

Lastly, the algorithms that the application is programmed to perform are designed and specified in general separately from the software. The software application is only a materialization of the algorithm. Therefore a bug or a malfunction in the software is completely different than, and should not be confused with a bug or malfunction of the algorithm.


... if that wasn't enough, there's an implementation of the same specification running on the other computer with entirely different code, and the two implementations are constantly checked against each other.


This protects against "software bugs/problems", but NOT against "algorithm bugs/problems". An algorithm "bug" is materialized in both implementations, and unfortunately is railing each of the two implementations into the same "bogus" behavior.

[DozyWannabe]

So how many "algorithm bugs" (aka logical errors) do you see manifesting in this accident? Because I still don't see any.

And it was quite possible for an application to take out other applications on home and business OSes until very recently (until Windows NT4/2000 and MacOS X to be precise), because the previous generation did not have adequate "siloing" of running tasks.

We're getting *way* off-topic here though - it was an analogy, not an exhaustive description - and your version lacks the main point I was trying to make, which is that real-time systems in aircraft are not "centralised" around an OS in the same way home and business computers are.

[airtren]

You show me a post where I said the aircraft and systems were perfect.



There is progress, with the extending of the lack of perfection to "aircraft" and "systems" from "software" and "design".. .

At the risk of sounding juvenile, I bet you can't.How much?


Not at all, I've stated outright that I don't think it's as big a deal as some are making it out to be, and I'll give you some reasons if you like:
#1. More than 30 UAS incidents in the A330/340 passed without incident. If not being able to see/feel the other pilot's sidestick was a safety concern, more of them would have crashed
#2. At least two aircraft equipped with interconnected yokes had a similar LOC/stall/crash event, one of which shows evidence that the F/O didn't like what the Captain was doing and did not overrule him.
#3. The sidestick design was approved by one of the most respected test pilots and safety gurus of his day.


On #1, "Diagnostic" has pointed out well and sufficiently the issues with it.
How many more casualties are necessary? to consider everything that may be a weak point important, or a “big deal”?
On #2, You're simply making my point about the SS location and virtual secrecy problem, and that of the "yoke" supporters, which is that the F/O saw quickly and understood well what was wrong. Why he didn't intervene is a completely different matter.
On #3, So what? I recall that others on this Forum refuted this point a while back, and you still think it is a "reason". Furthermore, you should know this if you have the expertise you've advertised: the approval of a tester cannot make a product, which is tested within certain limits, bug free!!!

To conclude, these are non-reasons, i.e. zero (0) value, relative to the AF447 case...

You should here what system architects from various industries say, about the "lack of visibility/virtual secrecy" of the A330 cockpit, and how this becomes an example of a typical bad choice for the control center of a critical mission system.

Well, when one has been here 9 years and has seen the same people make the same arguments over and over again, it's difficult to resist noticing and commenting on the pattern.
So, you had your self assumed badge for about 9 years? I've joined in July 2011, and your ""anti-Airbus brigade" defense badge" is outshining anything else that I could notice of similar nature.

As, I said before, I think you should reflect on this: do you really think Airbus needs this type of help?

I hope I've answered your questions, so as such I see no systems weakness in the design other than the pitot tubes.

Please clarify, elaborate, explain this, as it is quite unclear what you mean.

Perhaps you'd be kind enough to give me the benefit of your opinion on the matter.There is more in your queue that need processing.

[Organfreak]

[OF's operating system has experienced a fatal error and will now shut down]

[airtren]

And it was quite possible for an application to take out other applications on home and business OSes until very recently (until Windows NT4/2000 and MacOS X to be precise), because the previous generation did not have adequate "siloing" of running tasks.
14 -15 years is "recent"? There are people that made a profession from looking for holes in the "virtual fence" between OS and applications to use that to do damage, and others to close, or fix these holes, and prevent such damage.


We're getting *way* off-topic here though - it was an analogy, not an exhaustive description - and your version lacks the main point I was trying to make, which is that real-time systems in aircraft are not "centralised" around an OS in the same way home and business computers are.It's very far from an exhaustive description. Among other things, I think I've made that difference clear, between a Home Computer OS and applications, and a A/C's real-time computer OS, and application, which is why I wrote it.

[Clandestino]

Well sir, now that we have AF447, maybe they will reconsider, eh? Are certifying authorities always right the first time?
Where is the icon for 'pppfffttt!'?

They won't. So far no one has come with solid reason why they should. Perhaps I'm mistaken, but I don't think that powers that be consider statements preceeded by "I think", "I feel", "I find" and "I believe, made on anonymous forums worthy of their attention. Those who really believe they can contribute to improvement of certification standards should better send their signed opinions to relevant authorities instead of airing them on PPRuNe and similar fora.

What I find disturbing is that the airplane (AB) was designed to prevent such an event, but failed.

Given current level of technology, it wasn't and it couldn't be designed to protect from stall when having no realistic airspeed measurement. Of course, if you have idea how to overcome it, I would be delighted to hear it.

If the AF447 crew had an AOA indication and had been trained to use it, the only valid explanation for allowing the stall would be a death wish or both pilots sleeping.

They had aural indication of excessive AoA.

I doing ok Clandestino, thanksSo you realize the aeroplane was stalled. Do you realize, that when stalled all bets regarding controls authority are off except that it should be sufficient to unstall the aeroplane if appropriate control inputs are applied timely? Alternatively, if such criteria can not be met, aeroplane has to be equipped with automatic stall prevention device, colloquially known as pusher. Aeroplane was pitching down even with full nose-up elevator, when power was reduced so there is no need for precise pitching moment diagrams to see that connecting AF 447 with horror stories of irrecoverable stalls and swept wing pitch-ups is not red but infrared herring.

Then we both agree that both elevators should show a full down deflection.
If it is true, then both of you are unaware of lag associated with hydraulic powered controls.

An incorrect instrument.

So far there's no indication that any instrument on board of AF447 failed. ADRs correctly measured pressure in total line. That it wasn't total pressure is not instrument failure but probe clogging.

For a Curtiss Jenny .. a pitot tube clogged was not a very important problem ... for a Airbus or other brand using automation .. it's a crucial data loss It's manageable. Same way it was on JN. Attitude + power.

anyone clearly told us why the PF's 'ATT/HDG' was changed to 'FO on 3' where I think it stayed and what that would have done in the circumstances? I'm certain it's just me but I couldn't find reference to the occurrence mentioned in interim3, could you please direct me?

Thanks, my FCOM/AOM shows ADIRU input into the ISIS

Might be that airworthiness requirements got relaxed but on older Airbi it's not ADIRU signal input, it's shared pressure lines on stby instruments and ADR3. For pilots & maintenance folks it is of utmost importance to be able to tell the difference between the two.

I have been in a 319 that failed to respond to SS input asking for nose down. I was maneuvering, avoiding one buildup and flew into another which was a substantial updraft. I had already pitched for green dot trying to climb above the first buildup and when I flew into the second updraft the aircraft failed to respond to my nose down, fwd, SS input for a couple of seconds. I assumed at the time that the updraft caused a "g" loading that fooled the ELAC. The buildup was small and we flew out of it in a few short secondsThis is a very serious occurrence, sir. Could you please provide relevant NTSB reference (or local investigating entity's one, if it was international operation).


Note that only 13 UAS incidents had sufficient data available for the BEA to do a sensible review of them. Sure, none of the other flights crashed, but several were not handled according to the QRH,

Not a single flight where analysis was possible was handled IAW procedure. Atmosphere doesn't care if you use QRH as crutch, as long as you keep the AoA in the band that assures that the aeroplane keeps flying.

not all of them went into Alt* law

Yup. One out of 37 did not. Thirty-six out of thirty-seven went into alternate law. Some got stall warning. So pushed. Not pulled.

meaning that subsequent actions cannot sensibly be compared to AF447, etc. etc.

Eh?

So, are you suggesting that the crew for AF447 were not properly selected....?

No. I'm just suggesting that technical analysis clearly shows that most of the AF447 puzzle solution is in HF domain.


So .. are the AF447 airline pilots or not ?

1. Their paperwork has shown no anomalies so in the eyes of the law, they were.

2. Once upon a time there was a certain senior training captain who was smiling from the airline advertisements. Once he made a beginner's mistake of taking off without clearance. So died. Took 582 people with him. Do we call him non-pilot for that?

[DozyWannabe]

There is progress, with the extending of the lack of perfection to "aircraft" and "systems" from "software" and "design".. .

What does that even mean? You're starting to sound like bearfoil again.

How much?

On #1, "Diagnostic" has pointed out well and sufficiently the issues with it.
How many more casualties are necessary? to consider everything that may be a weak point important, or a “big deal”?

That the industry has a bad habit of "regulating by counting tombstones" is an uncomfortable truth, butthe point I was trying to make was that in the vast majority of those cases, the Airbus flight deck layout was more than enough to effect a recovery and arrive at their destination in one piece even if, as Diagnostic says, mistakes were made in the initial handling. That says to me that the design works at leas tas well as any alternative as far as the mission as a whole is concerned.

On #2, You're simply making my point about the SS location and virtual secrecy problem, and that of the "yoke" supporters, which is that the F/O saw quickly and understood well what was wrong. Why he didn't intervene is a completely different matter.

You'll be surprised to note that I disagree emphatically. If you compare the CVRs. both the Birgenair F/O and the AF447 PNF were well aware that the aircraft was not being handled correctly, but instead of taking control, kept making suggestions to the handling pilot. In the case of AF447, it would appear that the PNF was waiting for the Captain's approval to take control from the PF, and in the case of Birgenair the PF making a hash of it *was* the Captain.

On #3, So what? I recall that others on this Forum refuted this point a while back, and you still think it is a "reason". Furthermore, you should know this if you have the expertise you've advertised: the approval of a tester cannot make a product, which is tested within certain limits, bug free!!!

No-one ever said it was bug-free, it simply passes the certification requirements on reliability that the non-digital predecessors of the instrumentation had to pass. I don't recall being "refuted" either, so if you'd care to furnish me with an example, I'll catch up.

You should here[sic] what system architects from various industries say, about the "lack of visibility/virtual secrecy" of the A330 cockpit, and how this becomes an example of a typical bad choice for the control center of a critical mission system.

What systems architects? Show me. I can cast-iron guarantee you that you'll find just as many - if not more - who say the system is fine. You keep using the phrase "virtual secrecy", and I do not think it means what you think it means.

So, you had your self assumed badge for about 9 years? I've joined in July 2011, and your ""anti-Airbus brigade" defense badge" is outshining anything else that I could notice of similar nature.

Blow me down if I'm not being judged on 9 years of contributions based on 4 months of an occasionally heated discussion on one incident - and you accuse *me* of extrapolation!

In any case, the people I'm talking about materialised around 2004 and they blanketed any Airbus related thread with links to the website of one Norbert Jacquet, and later Henri Cornus - both former Air France Captains-turned-internet cranks who blame Airbus for the loss of their jobs and prestige. Some melted away over time, some are still around.

As, I said before, I think you should reflect on this: do you really think Airbus needs this type of help?

I'm not trying to help Airbus, I'm trying to get to the bottom of the issues behind the accident, and rehashing 20-year-old arguments about computers in the cockpit, yokes and feedback are getting in the way of that. The reason most of the more esteemd members of this board gave up on this subject months ago is because it always comes back to the same old same old. I only bother because I don't want to see Jacquet- and Cornus-sourced misinformation reprinted in the national press, whose journalists clearly know no better.

There is more in your queue that need processing.

I'm not going to be CONF's monkey, and I'm certainly not going to be yours.

2. Once upon a time there was a certain senior training captain who was smiling from the airline advertisements. Once he made a beginner's mistake of taking off without clearance. So died. Took 582 people with him. Do we call him non-pilot for that?

And, lest we forget, his fellow countrymen and pilots so categorically refused to believe that their premier pilot could make such an elementary mistake that they tried to blame the controllers (based on their assertion that they heard a word that sounded a bit like "futbol" on the ATC tape, which none of the other investigators heard), and the crew of the other aircraft involved (based on the fact that they did not turn off at the C3 exit, which was a practically impossible turn for a jumbo to execute, and elected to use C4 instead). To this day, the Dutch report still makes these assertions.

[BOAC]

I'm certain it's just me but I couldn't find reference to the occurrence mentioned in interim3, could you please direct me? - bottom of P90

[Organfreak]

Originally Posted by Organfreak
Well sir, now that we have AF447, maybe they will reconsider, eh? Are certifying authorities always right the first time?
Where is the icon for 'pppfffttt!'?
Posted by Clandestino
They won't. So far no one has come with solid reason why they should. Perhaps I'm mistaken, but I don't think that powers that be consider statements preceeded by "I think", "I feel", "I find" and "I believe, made on anonymous forums worthy of their attention. Those who really believe they can contribute to improvement of certification standards should better send their signed opinions to relevant authorities instead of airing them on PPRuNe and similar fora.

Excuse me, but I fail to see how your response (to my comment to DW!) has anything to do with my simple suggestion that perhaps the authorities will reconsider what they certified, since I suggested nothing to them, nor would I. Only a complete fool would believe they could influence the authorities from here. You're changing what I said into something else! I really don't get where you're coming from. :confused:

[OK465]

Having once again learned something new here, in the future to avoid lag, I will plan on making all flight control inputs before I'm aware I need them.

[Organfreak]

Clandestino typed:
They had aural indication of excessive AoA.

What does that mean??? Wind noise??? FAs falling base over apex???

[airtren]

There is progress, with the extending of the lack of perfection to "aircraft" and "systems" from "software" and "design"..
What does that even mean? You're starting to sound like bearfoil again.

So now what? you now realize what it means, and you're taking it back?

You went from saying that "design" and "software" are not perfect, to "systems" and "aircraft" are not perfect, and when I make a note of the progression, and progress, you're asking me what it means?

How does that sound? I would say just like yourself.

Have you reflected, thought, been aware what it means when you said what you've said?
.....

Can you clarify your statement of the Airbus "design" problem with the pitot tubes, per my earlier request?

Or is just a throw in the air, as you know well that the "pitot tubes" are already "done deal", and there is nothing to loose, or gain, by saying what you're saying?

How much?
You're answering with a question? You've mentioning betting, its yours, you want someone else to give your words their worth?



That the industry has a bad habit of "regulating by counting tombstones" is an uncomfortable truth, butthe point I was trying to make was that in the vast majority of those cases, the Airbus flight deck layout was more than enough to effect a recovery and arrive at their destination in one piece even if, as Diagnostic says, mistakes were made in the initial handling. That says to me that the design works at leas tas well as any alternative as far as the mission as a whole is concerned.

If there is anything wrong with the industry counting the tomb stones as an indication when there is time to get serious, is that it waited way too long, not that it takes actions, when there are fatalities.

You're clearly wrong, as based on your badge, you're not willing to admit that an airplane full of passenger casualties didn't happen earlier by pure luck, or science of statistics, and that there is a very simple and obvious factor in the cockpit that made it more difficult to isolate immediately the mistakes and correct them, as to prevent the loss of 228 lives, a factor that is recognized by other airline manufacturers, and by other industries.


You'll be surprised to note that I disagree emphatically. If you compare the CVRs. both the Birgenair F/O and the AF447 PNF were well aware that the aircraft was not being handled correctly, but instead of taking control, kept making suggestions to the handling pilot. In the case of AF447, it would appear that the PNF was waiting for the Captain's approval to take control from the PF, and in the case of Birgenair the PF making a hash of it *was* the Captain.
No, the PNF had a suspicion, a guess, a hunch, but never knew, couldn't know for sure, with 100% confidence, which is why he could not tell the Captain, when the Captain rejoined the cockpit what's going on, why, and how things got there.

We have the PF's SS actions on the FDR traces, and we are in such a comfortable spot to be able to say what is wrong with those SS actions, as the traces clearly tell us.

But you're not willing to admit, that one of the reasons the Captain failed until the end, like the PNF, to see exactly what those actions were, is what is so obvious to many - the lack of visual contact, the lack of ability to see the positioning of the stick, and the actions on the SS, which yes, is "a virtual secrecy" created for the direct PF actions on the SS, for those that are in the cockpit.



There is more in your queue that need processing.

I'm not going to be CONF's monkey, and I'm certainly not going to be yours.
You would be your monkey, as your input queue is yours, and the responsibility to manage it properly is yours.

I'm not trying to help Airbus, I'm trying to get to the bottom of the issues behind the accident,... Really?

Per your own posts, you're trying hard to influence and control this Forum, as to guide it into the belief that the only problem with the airplane is the problem known well before the accident - the pitot tubes - and that the ample data provided by this accident show no problem with it.

You would have to do a lot to change the credibility perception for statements like the one I just made.

and rehashing 20-year-old arguments about computers in the cockpit, yokes and feedback are getting in the way of that. I have no idea what was the discussion or problems pointed out were years ago. I looked at the AF 447, case and data, with no dog on the track, and what's obvious is there obvious. The fact that similar discussions existed before, is just an indication that the problem existed from day one.

[gums]

Salute!

- As mentioned, there can be lag in control surface position versus control stick/yoke/wheel position and rate of application ( hereafter referred to as "stick").

"lag" can be implemented to get a better handling jet or to keep you from ripping the wings off, and it can be modified by pure mechanical doofers in the actuators, feedback of surface forces in the actuator, or firmware/software.

For example, observe the Viper or Typhoon at your next airshow ( two FBW jets). Note how quickly the jet stops rolling. Lag? Yep. The roll command implements a lag filter when rolling into a bank, and a reduced lag filter when relaxing the stick. So simply relaxing pressure, or deflection of the stick, gets you back to the trimmed roll command or "protected" bank angle that the 'bus has in some laws.

- We must distinguish between "instruments", displays and sensors. Granted, the actual pneumatic sensors on the 'bus may have accurately measured AND displayed the poor data, but many folks call that "instrument failure". The AF crew even calls out " we have no indications". So what does that mean? Is it the sensor or the actual display?

With known unreliable speed at the outset of the story, when did the system ( input device, sensor, display) become reliable again? Is the pneumatic vertical velocity valid? Is an inertial vertical velocity display available to use as a crosscheck? Hmmm....

- AoA, one more time.

Why ignore the AoA sensor inputs for stall prevention/ stall indications/displays? Is the 60 knot speed doofer a poor design implementation versus a simple weight-on-wheels "switch"?

Speed ain't a good thing to use for a stall indication. You can stall at almost any speed in many planes ( high performance jets usually cannot stall when flying at the speed of stink, heh heh, as you hit structural limits before AoA limits). You stall because you exceeded some AoA.

You don't need a full time AoA indication. In the Viper, we only had an AoA "bracket" in the HUD when gear was down, and used it for best approach speed. Lots more accurate than a "speed" we got using our gross weight and configuration. Easier, too, for we single-seat types. Ask 'bird, Retired, Smilin', et al. The U.S. Navy jets had a full time AoA display called an "indexer" that told you to lower the nose or raise the nose. The A-7, F-4 and F-18 of my era when the Earth was still cooling, but aerodynamic principles were well-established, had a full time AoA indication in the HUD.

Stick and/or rudder pedal shakers are neat, as are aural warnings. But we saw the AF crew seemingly ignore the aural indication. Not much re-design effort/testing required to add a "vibrator" to the stick. But would it be valid?

"we have no indications"........
++++++++++++++++++++++++
I always wonder why the new airliners don't have a HUD.

After all, they have only been around since the late 60's.

A HUD is invaluable when landing in poor weather, and it ain't too shabby for basic climb, cruise, descent. Using inertial data for a flight path doofer ( FPM), it's an excellent thing for crosscheck with the steam gauges or cosmic flatscreen displays such as the 'bus and others utilize. Seeing the FPM caged at the bottom of the HUD is a great indication that you are descending, regardless of your pneumatic system displays. Then there's the pitch lines to show the actual angle your jet is flying and pitch attitude if you have a body reference symbol ( like your basic attitude indicator). Sheesh, that HUD will spoil your crosscheck in a hurry, and it takes lottsa discipline to include the steam gauges.

Lastly, I do not go with the yoke/wheel crowd. For some, the visual or tactile feedback might help. But mostly you see what's happening on the displays or outside the windshield and ask the other guy what he's doing if you don't understand what's happening. BTW, I am not a true dinosaur, I evolved into a bird.

[jcjeant]

Hi,

Clandestino
Quote:
Originally Posted by jcjeant
For a Curtiss Jenny .. a pitot tube clogged was not a very important problem ... for a Airbus or other brand using automation .. it's a crucial data loss

It's manageable. Same way it was on JN. Attitude + power.Pilot handling was not exactly my point ...
For the JN when Pitot tube clogged you loss airspeed indication (visual) and no more
For the Airbus when pitot tubes clogged you loss airspeed indication (visual) and also a important data needed for the automation system .. and that is the most important point (design of the automation system)

This is a very serious occurrence, sir. Could you please provide relevant NTSB reference (or local investigating entity's one, if it was international operation).Methink .. such incident will not show in any investigating entity's unless pilot made a report to airline .. and this airline send it to investigating branch office
I think (by what I read about reports and experience backup) that this event no deserve to be in a investigating entity archive
I can be wrong ... if it's the case the OP will certainly correct me in his answer

Do we call him non-pilot for that? This particular day and time .. yes .. he was no more a pilot .. he forget he was a pilot .. and he was just a man trying to return as soon as possible at home

OK465
Having once again learned something new here, in the future to avoid lag, I will plan on making all flight control inputs before I'm aware I need them. :) :ok:

[Clandestino]

- bottom of P90 Thanks, I missed that :ok: Seems that someone at BEA messed up by providing ADR switching traces twice, instead of ADR and IR switching. They have time to fix it in final. As there were no IR failures or disagreements recorded, seems that switching of RH IR source from IR2 to IR3 wouldn't make a difference to displayed attitude.

For example, observe the Viper or Typhoon at your next airshow ( two FBW jets). Note how quickly the jet stops rolling. Lag? YepDid just that this summer at Zeltweg. Couldn't help but notice that both of them are combat airplanes, implying that they're on the opposite side of stability/maneuverability spectrum compared to passenger transports. If maneuverability is primary design concern, it's easy to reduce control lag by installing powerful hydraulic actuator. If not - weaker one will do just fine, it will be lighter, will strain hydro system less and require less beefing up of the structure it is attached to. That's why AF447 elevator traces shows gradual reduction from full nose down when forward stick was applied and not instant stop-to-stop wham.

Why ignore the AoA sensor inputs for stall prevention/ stall indications/displays? Stall prevention - with pitot clogged there is no way for ADC to discern whether AoA or airspeed is faulty so it proclaims itself unreliable. With all three ADRs out, to reduce the risk of wrong protection kicking in, air data based protections shut off and leave the problem for intelligent beings to solve. That's basically what is meant by very technical term "Flight control laws"

Stall indications - it wasn't ignored. It worked properly.

Displays - no legal requirement for AoA displays to be fitted. With thousands of airliners flying safely every day without them and dozens of crews solving UAS just by reference to attitude and power, I don't find the logic behind not requiring AoA gauge in cockpit faulty.

Is the 60 knot speed doofer a poor design implementation versus a simple weight-on-wheels "switch"?Not quite. Since you have to introduce ADR input into stall warning system to cope with Mach effect on critical AoA, having 60kt cutout is actually simpler than adding WoW input and with it another possible failure point.


The U.S. Navy jets had a full time AoA display called an "indexer" that told you to lower the nose or raise the nose. Thanks for the info. On PC-9 indexer comes alive only when gear is lowered, I assumed it is just for landing on every military airplane.

I always wonder why the new airliners don't have a HUD.I am afraid that we get new equipment only if it makes economical sense to someone in charge. I have Head-up Guidance System in my Q400 because it was cheaper to graft IRS and HGS on her to make her CAT3A capable than to develop autotorque and autoland-capable autopilot.

Sheesh, that HUD will spoil your crosscheck in a hurry, and it takes lottsa discipline to include the steam gauges.
Not to mention your landings will become more precise and softer with the help of the little birdie and then one day you'll be all f-ed up when your HGS gets MELed and it's back to switching between head down and up on landing again.

Pilot handling was not exactly my point ... Why? Pilot handling is exactly what put AF447 into trouble.

For the Airbus when pitot tubes clogged you loss airspeed indication (visual) and also a important data needed for the automation system .. and that is the most important point (design of the automation system)It would be important if A330 is impossible to fly without automatics. Well, it was designed to fly with computers and sensors badly shot up. It's not heuristics but many thousands of hours spent on carefully designing and testing the plane.

I think (by what I read about reports and experience backup) that this event no deserve to be in a investigating entity archiveReading the description, it could be either hitting the low G protection at -1G and that makes absolute hell of cabin even with everyone strapped in or serious failure of flight controls system. Where I live either option is heavy incident, will leave massive traces on QAR that would be picked up by the FDM so non-reporting would result in tea without biscuits and it has to be investigated by government appointed investigation commission.

he was no more a pilot .. he forget he was a pilot ..Since you say so, is this applicable to the case we're discussing, too?

[Old Carthusian]

Diagnostic
I am a private person and I value my privacy very much. That is why you will not see any information about my flying experience on my private page. It is also why I have not checked up on yours or anyone else's. I take everyone by what they write and that means the occasional mistake that they may post. But just this once I will make an exception - I received my instrument rating back in 1985.
I joined this board to learn about this particular incident but what I am learning disturbs me greatly. This doesn't seem to be about aircraft but about cultures of neglect and arrogance that develop in the professional piloting world and that scares me. We have Pan Am back in the 1970s, Korean Airlines in the 1980s, Air France now. The implications are very disturbing - almost as if there is a disease that can infect any airline. Arguments about automation and greater computing taking away flying skills may have some bearing but not really. Pan Am's culture happened in the yoke/mechanical linkage era. So did Korean's. There are thousands of Aibuses flying around the world - probably at least 50 of them are in the air as I write. All of them using sidesticks. There are thousands of Boeings - they use yokes don't they? Both input methods are equally valid and both have their adherents. However, the yoke would not have saved the aircraft in this incident because the issue is cultural not mechanical.

[AlphaZuluRomeo]

So how many "algorithm bugs" (aka logical errors) do you see manifesting in this accident? Because I still don't see any.
For the record, and despite I doubt it would have changed the outcome in the light of the crew actions, I see two of them:
1/ the non-inhibition of the nose-up autotrim when stall warning is active
2/ the inhibition of the stall warning under 60kt IAS (even if I understand the logic behind the inhibition, I still think it may be worth reworking that bit of logic)

And perhaps a 3rd and 4th, but as I don't know the logic behind I'm not qualified to fully comment:
3/ the V/S switching source from air data to inertial (and back); it occured in AF447 and its consequence was a non-readable/unreliable/unrealistic displayed (air data sourced) V/S, while at the same time a reliable/realistic V/S value (aka inertial sourced V/S) was available (for the system).
4/ the non-inhibition of the F/Ds (by the system) when an UAS situation is detected: why? A/P & A/THR may (and have) been dropped, why not the F/Ds as they may give unreliable directions in such a situation?


Nonetheless, I still fully agree with Clandestino here (my bold):
No. I'm just suggesting that technical analysis clearly shows that most of the AF447 puzzle solution is in HF domain.

-----------

For the Airbus when pitot tubes clogged you loss airspeed indication (visual) and also a important data needed for the automation system .. and that is the most important point (design of the automation system)
Yes I agree. And because of data missing, when tubes get clogged you have reversions in various systems.
But what do you make of that statement? Are you advocating that, because "automation" (which part(s) ? flight controls? A/P? A/THR? all of those? more?) uses air data, and air data is not 100% reliable, the industry should renounce "automation"??
I'm sure I must have misunderstood your point. Would you be kind enough to elaborate?

-----------

Now, on a more general topic, is it possible going back to the ball, i.e. leaving the players alone? :rolleyes:

[infrequentflyer789]

Clandestino typed:
What does that mean??? Wind noise??? FAs falling base over apex???

[Regarding aural indication of excessive AOA]

I would think it's fairly obvious he means the a/c shouting "stall" at them continuously for almost a minute - but then it seems it wasn't obvious to those there on the night...

Where I differ from Clandestino and others is that I am not sure the binary on/off stick shaker or stall warning is an adequate subsititue for an AOA gauge once you've managed to get yourself stalled. Shaker / warning won't tell you any different between "you're nearly stalled", "you're stalling", "you're well stalled" and "you're more stalled than any test pilot ever went...".

Maybe the warning should get louder, shout different things, shake stick harder... or maybe it should be a cue to look at the instrument that tells you exactly how far you are from flying.

That said, I have a suspicion it would have made little difference on 447 - the AOA would quickly have been pegged at max (25) and then disbelieved.

[AlphaZuluRomeo]

There are thousands of Aibuses flying around the world - probably at least 50 of them are in the air as I write.
At least! Just now, 221 FBW/SS equipped Airbii are broadcasting (ADS-B) in zones covered by private receipters of the FlightRadar24 network (which is most implanted on Europe, and it's night over it at present). And to compare: 293 B7xx at the same time.

/off topic

[airtren]

For what it's worth, I was PM'ed by the same person some time ago stating that you and Lyman (then bearfoil) were the same person. If this turns out to be false then you have my apology.
So, you've echoed repeatedly publicly an idiotic statement sent to you via a PM - I have no idea who the "same person" you're mentioning is - and offer a conditional apology?

The Moderator deleted your first post, after you refused to do it at my respectful request, but then you keep repeating it, as soon as I start posting, as a tool of intimidation.

You need to do a lot better than this post.

You can start with your own computer expertise - as an advertised software engineer, you should do a lot better - as you seem to have no clue on detecting network applications impersonations, continue with your interaction with the Moderator, continue with a better management of your tactical arsenal devices and finally improving your apology section.

[airtren]

..... Shaker / warning won't tell you any different between "you're nearly stalled", "you're stalling", "you're well stalled" and "you're more stalled than any test pilot ever went...".

Maybe the warning should get louder, shout different things, shake stick harder... or maybe it should be a cue to look at the instrument that tells you exactly how far you are from flying.

.
Here is a post on the topic, which tangentially points out the 3 different Stall states, and possibility to have an error message for each.

http://www.pprune.org/tech-log/456874-af-447-thread-no-5-a-38.html#post6598193

[DozyWannabe]

For the record, and despite I doubt it would have changed the outcome in the light of the crew actions, I see two of them:

OK, that's cool - and that was all I was asking for. I'm puzzled as to why other posters regard it as though it's like pulling teeth and expect me to jump through hoops for them before I get a reasonable answer. Let's have a look!

1/ the non-inhibition of the nose-up autotrim when stall warning is active
2/ the inhibition of the stall warning under 60kt IAS (even if I understand the logic behind the inhibition, I still think it may be worth reworking that bit of logic)

So first of all, looking at these in a cursory manner, these are not "logical errors" in terms of software engineering - the term has a very specific meaning which is whereby programming instructions that are syntactically correct nevertheless produce erroneous return data. What you're describing here is a situation where a system operating in the field has produced results that highlight potential issues going right back to the specification (or indeed a set of circumstances that the original specification did not or could not take into account) - the result of which is what us nerds refer to as a "change request".

Now I've got that rather dull bit of nitpicking out of the way, let's dig in.

1. Limiting the autotrim in response to a stall warning sounds good in theory, but you're going to have two major problems right off the bat. The first is quite simple, and that is "what happens if the stall warning is false?". I can foresee a couple of situations off the top of my head where that could be more dangerous than letting the trim run. The second is a bit more esoteric and complex, and indeed can apply to all the things you're talking about, and that is the increase in complexity such a change will add to the system as a whole. Determining the knock-on effect that change would have is a very involved process and the logic paths would have to be scrutinised at a very in-depth level, and of course you run afoul of the old engineering maxim that adding complexity is increasing the number of potential points of failure. That said, it looks like the A320 has a hard nose-up limit on the autotrim in Alternate of 3 degrees, while the A330 does not. I'd be interested to know what they discovered inbetween development of the two airliners that led to that change. I think that a hard limit would probably be a more effective solution than checking against Stall Warning status (which is after all in a completely different subsystem and may or may not be valid).

2. I wouldn't be surprised if most airliner designs of a mid-80's vintage or later have similar logic. Determining whether a stall warning is valid or not has been a tough nut to crack for a long time, and in an overwhelming majority of cases, the limits set probably make good sense - I mean this is the only case where it has been perceived as an issue and in order to make it one the aircraft was taken further out of the flight envelope than any test pilot would dare attempt. On paper it looks sensible, because Stall is a function of AoA, and the limit of the AoA vanes' effectiveness as reported by the supplier is <60kts. I saw talk of using a WoW switch earlier, and I don't think that the designers would assume that if the computed speed is less than 60kts then the aircraft must be on the ground, given how in-depth they went and how many permutations they went through to arrive at the spec they did. In their shoes I'd be thinking "if we know that the data is going to be unreliable past this point, then it's probably best discarded". Unfortunately they didn't bet on the set of circumstances that caused AF447 (specifically "what if an aircraft was held in a stall to the point where that limit is reached?"), and even those who have no particular love for Airbus have to admit it's an edge case to end all edge cases. I have no clue how easy or difficult it would be to latch the current stall warning status when that limit is reached, and I foresee complexity arising from what to do once a recovery has been effected (namely "We've latched stall warning because we can't trust the data, so at what point can we start trusting it again?").

And perhaps a 3rd and 4th, but as I don't know the logic behind I'm not qualified to fully comment:
3/ the V/S switching source from air data to inertial (and back); it occured in AF447 and its consequence was a non-readable/unreliable/unrealistic displayed (air data sourced) V/S, while at the same time a reliable/realistic V/S value (aka inertial sourced V/S) was available (for the system).
4/ the non-inhibition of the F/Ds (by the system) when an UAS situation is detected: why? A/P & A/THR may (and have) been dropped, why not the F/Ds as they may give unreliable directions in such a situation?

These are definitely trickier as they depend on a given reading of the DFDR data in Interim #3.

3. Are you sure that the V/S trace indicates mode-switching from air data to inertial and back? I was told that the extreme variations towards the end of the trace indicate the static ports being fouled by the airflow induced by the stall, and it is not until the computed airspeed is in the low 100kts area (by which point the stall is well-established) that the readings start to look wrong

4. For starters, I'm not sure how to read the FD trace accurately, but they are inhibited when airspeed data is lost (as you'd expect them to be) - those spikes during the period of actual UAS indication might indicate attempts to re-engage them manually, but I have to defer to more knowledgable folks there. The FDs come back on (as they are designed to) when the airspeed data returned and then switch off again as the aircraft slows to the point where presumably the stalled air is playing merry havoc with the pitot/static and AoA sensors

In these cases, the situation the aircraft found itself in was so extreme that I wouldn't know where to start in terms of getting reliable and accurate data. I wonder what difference having the BUSS might have made?

[jcjeant]

Hi,

AlphaZuluRomeo
But what do you make of that statement? Are you advocating that, because "automation" (which part(s) ? flight controls? A/P? A/THR? all of those? more?) uses air data, and air data is not 100% reliable, the industry should renounce "automation"??Air data is 100% reliable .. provided that air data is gathered by a reliable captor
So far ... it's proofed that under certain conditions (who are common for a A330 or any modern airliner) those captors are not reliable and can send false or not information at all to the automatic system
So the industry must not renounce "automation" .. provided they correct the weaknesses
Apparently nothing positive was made for correct the problem ... but paper work and modified training
It's agravated by the fact that this problem is know from ages ..
The original problem stay hidden rear the corner

Clandestino
Quote:
Originally Posted by jcjeant
he was no more a pilot .. he forget he was a pilot ..

Since you say so, is this applicable to the case we're discussing, too?

I read in the BEA report N°3 (CVR extracts) that the pilots are telling .. they don't understand and they have no more indications
Or .. the BEA affirm that all was functioning normally (less airspeed indications) and the plane was airworthy
So how you call people facing instrument panel working in a plane working and who are telling they understand nothing ?

[DozyWannabe]

So, you've echoed repeatedly publicly an idiotic statement sent to you via a PM - I have no idea who the "same person" you're mentioning is - and offer a conditional apology?

It didn't seem idiotic at the time, it wasn't just one person passing that information along and I had (and still have) no reason to believe that they would deliberately misinform me, in fact it's likely someone misinformed them.

The Moderator deleted your first post, after you refused to do it at my respectful request, but then you keep repeating it, as soon as I start posting, as a tool of intimidation.

In fact the moderators deleted a whole swath of posts from that period and at no point was I contacted directly by the moderating team saying I had erred or otherwise - you make it sound like I was singled out for admonishment when it was not the case.

You can start with your own computer expertise - as an advertised software engineer, you should do a lot better - as you seem to have no clue on detecting network applications impersonations, continue with your interaction with the Moderator, continue with a better management of your tactical arsenal devices and finally improving your apology section.

Aside from the fact that I participate in these forums as a way of taking my brain off the software development track for short periods of time, I have no access to the IP logs of this forum and therefore no way (or at least no *legal* way) of telling - other than building relationships with knowledgeable and trustworthy posters - people are who they say they are. The heads-up came from more than one person, at least one of them had proven trustworthy in the past, and it happened during a period of a lot of people who had previously been curiously silent sticking their oar in, and at least one user going under two different handles (i.e. sockpuppeting). As I said before, none of the moderating team has interacted directly with me either privately or publicly, so I don't know what you're getting at.

If the information was incorrect then, as I said, you have my apology. Other than that I don't know what more I can say or do at this point.

[Diagnostic]

@Old Carthusian:

Hi,

I don't know why you're addressing a reply to me about your flying background - I didn't ask any question about it :)

My earlier replies to you were just trying to help correct the mis-description of what a nose-up AI indication means (or rather doesn't necessarily mean). That interpretation is especially relevant in the case of AF447 when stalled, of course. I thought I would try explaining it slightly differently, to see if that helped, since you were saying the same thing to multiple other members who were also trying to explain the fallacy of your statement as it was written (which you later explained was not what you really meant).

Someone else suggested the discussion about general AI interpretation was off-topic in this thread, and I agreed to stop. That's all :)

While I don't agree with all your comments below, since you've kindly explained some of your thoughts, here are some of my own...

The implications are very disturbing - almost as if there is a disease that can infect any airline.
I agree - since HF seems to be a significant contributor to this accident, and humans are involved as flight crew on other airlines, :) personally I have not concluded that only Air France CRM training / assumptions of hand-flying training requirements / etc. [add other human factors as needed] are likely to have been lacking at that time.

In fact I remember another pilot here (not AF as far as I know) who said a while back, that high-altitude manual handling training and high-altitude UAS training had been introduced on his airline after AF447. That suggests such training was also lacking on that airline too, prior to this accident - so AF was not alone, it seems.

Arguments about automation and greater computing taking away flying skills may have some bearing but not really.
Based on my reading, I politely disagree about the "not really". The paper by Dr Lisanne Bainbridge called "Ironies of Automation" seems extremely relevant here (I first found that paper a while ago, via a link in another accident report - NTSB, I think - this is not the first time that AP handed over to pilot, who seemed unable to grasp the situation from a "cold start"). This isn't a criticism of pilots - it's a limitation of humans IMHO.

Also the concept of "startle factor" (when automation unexpectedly hands-over to the pilot) was shown in an AF training slide in an earlier segment of this thread, so this issue is known. The man-machine interface (and humans not being well-suited to a monitoring-only situation, which is more & more the case with modern flying) makes me very interested in the effects of increased automation, and its part in accidents like this.

However, the yoke would not have saved the aircraft in this incident because the issue is cultural not mechanical.
Perhaps, perhaps not. I don't believe anyone can say that yokes "would not" have helped (nor that they "would have" helped) - we simply don't know, since we can't re-run this scenario with this crew (unless you have a time machine to re-run that flight in an A332 fitted with (preferably coupled/back-driven) yokes :) ). I've seen enough arguments from members here (some quite assertive!) with merit on both sides, to see that there are benefits (and deficiencies) to both systems.

LOC accidents with yoke-equipped aircraft as previously mentioned by other members, show that they are not a panacea. However I don't see how anyone could rule-out in this case, the possibility of the PNF being more assertive (e.g. perhaps taking control earlier) if he was more aware (by having the yoke pressed to his body) of the PF's extreme nose-up inputs. We can't ask him, so we'll never know whether that knowledge might have changed his behaviour :(

I will just point out that the CVR conversation at 2h 13m 40s seems particularly important regarding the [lack of] awareness of the other crew to the PF's inputs - especially since (according to the released CVR transcript), the PF was not verbally communicating his decisions & inputs most of the time. Would a yoke have improved this PNF + Capn awareness enough (and quickly enough) to change the outcome? I don't know, and perhaps only if the PNF or Capn caused a change in PF inputs (or one of them took control) earlier than this point in the sequence - but I doubt that a yoke would have made the PNF & Capn's awareness of the PF's inputs worse. :)

The HF part of the final report will make interesting reading, IMHO.

[TTex600]

Regarding my mentioned experience where a A319 did not respond to a nose down SS input: for the brief moment I was in an updraft, the nose did not follow the input - once I flew out of the updraft the nose came down and we continued as if nothing had happened......... Knowing that pitch is load factor demand, and being in a updraft/downdraft/updraft/downdraft situation, and considering that the nose came down as soon as I passed the building cumulus, and considering that the Bus behaved normally the rest of the flight, I chalked it up to being in an Airbus. To me, it was no different than waiting for the MCDU to finish "updating" the page. Airbus pilots will know what I'm talking about.

Sorry Clandestino, but you're being overly dramatic. No report was made because none was necessary.

[airtren]

OK, that's cool - and that was all I was asking for. I'm puzzled as to why other posters regard it as though it's like pulling teeth and expect me to jump through hoops for them before I get a reasonable answer. Let's have a look!

You are talking about pooling teeth?

I have asked you a clarification on your mentioning of the Airbus design problem with the pitot tubes, and you have not provided that yet. That's not even a new question like you've asked.

You get back exactly what you do, not answering the questions in your queue in a timely fashion......

But actually, I am on this, with my Smoke Detector ON so....


So first of all, looking at these in a cursory manner, these are not "logical errors" in terms of software engineering - the term has a very specific meaning which is whereby programming instructions that are syntactically correct nevertheless produce erroneous return data.

What you're describing here is a situation where a system operating in the field has produced results that highlight potential issues going right back to the specification (or indeed a set of circumstances that the original specification did not or could not take into account) - which is what us nerds refer to as a "change request".

Now I've got that rather dull bit of nitpicking out of the way, let's dig in.
The above maybe confusing, perhaps because of the travail to explain.

Here is an explanation in other words, as a secondary source:
The "logic" behind a program is the "algorithm".
An "error in the logic" of a program is an "algorithm error".
A "software error" or "software bug", is one where the logic followed by the software is correct, but an incorrect outcome or result occurs, in spite of the correct following of the logic, or algorithm.

In high level programming languages a bug is usually caused by incorrect programming of data fields, which pass somehow through the compiler's checks, and which result in handling data which are different than what they're supposed to be. In machine language, which is often used in real-time programming, it may be a slightly wrong programming instruction which is equivalent to the previous mentioned error - for instance the use by mistake of a "load word" instead of "load byte", or "store byte" instead of a "store word", and others...

A "software syntax error" is a typo in a program instruction or program line, which is detected by the compiler - or some smart text editors - and need be fixed, before the compiler would complete successfully its processing.of the program source code. "Syntax errors' are never present in production/running software, as the process of generating the software excludes them.

According to the documenting of the algorithms by Airbus docs, the problems can be identified as being in the algorithms. Therefore, at this stage it seems that the solution of the problem is at algorithm level, not at software level.

[CONF iture]

Having once again learned something new here, in the future to avoid lag, I will plan on making all flight control inputs before I'm aware I need them.
Still, one question remains : How long before ?
Let's expect the answer to be somewhere here :

http://i45.servimg.com/u/f45/11/75/17/84/70121610.jpg (http://www.servimg.com/image_preview.php?i=127&u=11751784)


Lastly, I do not go with the yoke/wheel crowd. For some, the visual or tactile feedback might help. But mostly you see what's happening on the displays or outside the windshield and ask the other guy what he's doing if you don't understand what's happening.
The idea Gums is that such question has no reason as the visible yokes have already spoken. Next move on the yoke will tell if correction is applied and applied in the direction you would expect.

Instantaneous non verbal communication - Priceless - IMO - of course.

[Old Carthusian]

Diagnostic
Thank you for your courteous response.
I agree that Dr Bainbridge's paper is very valuable in this respect but feel that with good training and professionalism such an effect can be mitigated if not totally avoided. Pilots should not really freeze and lose control if an aircraft does what it is designed to. However, as realistic training as possible is the key hear and this may well be lacking. Hard training, easy execution as the saying goes. From my studies of previous airline company cultural issues I think that automation is the way to go but there are caveats as you observe.
Whilst you are correct about the hypothetical nature of my comments on yokes I feel that the balance of probabilities bears it out. Given the actions of the flight crew that night and that the PNF did take some ineffective action before calling the captain I cannot think that a different input method would have changed things. I also think that the PNF comments 2:10:26 to 2:10:36 where he tells the PF to go back down three times are highly significant and indicate an awareness derived from his instruments. The PNF also warns the PF (2:11) to 'touch the lateral controls as little as possible' once again indicating an awareness of what is happening. I would suggest that a yoke whilst not making the awareness worse it wouldn't have made it any better.

[airtren]

It didn't seem idiotic at the time, it wasn't just one person passing that information along and I had (and still have) no reason to believe that they would deliberately misinform me, in fact it's likely someone misinformed them.
So, from one source, there are now multiple sources of PMs.
Whatever the extend of the ring was, the idiotic message went around, and it seems that nobody alerted the Moderator to delegate the impersonation problem to him.


In fact the moderators deleted a whole swath of posts from that period and at no point was I contacted directly by the moderating team saying I had erred or otherwise - you make it sound like I was singled out for admonishment when it was not the case. You have a problem with your parser - I said nothing to that effect.

But to help with your implying of unawareness of what was going on regarding your post, I will remind you that you were cc-ed on my communication to the moderator, so you were well aware of the link between your post, my reaction, my request to the moderator, and the removing of your post, so had plenty of info of why your post was removed.

Nevertheless you continued recently in two instances, with repeating the spreading of context of the older idiotic messages...


I have no access to the IP logs of this forum and therefore no way (or at least no *legal* way) of telling - other than building relationships with knowledgeable and trustworthy posters ....
This is so ridiculously amateurish ...

Do you need me to teach you how to act like a computer professional?

If you don't have access to the IP addresses, the Moderator does, and if he doesn't, the WEB master does, and so you should have asked the Moderator to look into it, if you had a suspicion, and wait for their answer, before posting publicly content of idiotic PMs... .

I am glad Organfreak made this sewer detective activities public, as it seems they went and go quite a bit.... Pfew, what a stink...


If the information was incorrect then, as I said, you have my apology. Other than that I don't know what more I can say or do at this point.The enjoying of the mambo-ing around the "if" conditional sentence is your choice...

[airtren]

The idea Gums is that such question has no reason as the visible yokes have already spoken. Next move on the yoke will tell if correction is applied and applied in the direction you would expect.

Instantaneous non verbal communication - Priceless - IMO - of course.
CONF iture,
It's my opinion too.

Between visual and audio perception, the visual is a lot faster. It's not only the speed of light, versus speed of sound difference, but the speed of reaction to one versus the other stimuli to the brain.

Perhaps it would be helpful to share what race car drivers are taught:

widen the eye scan to over both sides of the track, and forward from front of car until as far as possible, and monitor any change of color, reflection, or shape that is abnormal. Upon detecting a change, focus on it, determine what it is, and react if necessary. The transition from monitoring to focus, to reaction is fractions of seconds, enough to have a correct reaction in time to avoid critical accident situations - as at the speed of a race car, in a second or two, the distance covered maybe too long....

[Old Carthusian]

There are two problems with that argument. Firstly, distance - at the distance in the cockpit the difference between audio and visual perception is so infinitesimal as to be totally disregardable. Understanding and interpretation are the key.
The second issue is that visual perception is worthless without a frame of reference and that is why a yoke is no more superior than a sidestick. A yoke moves - how far is a significant movement? Who decides the frame of reference?

[HazelNuts39]

"We've latched stall warning because we can't trust the data, so at what point can we start trusting it again?"
CS 25.207(c) Stall warning: Once initiated, stall warning must continue until the angle of attack is reduced to approximately that at which stall warning began.So how about: IAS >60 kCAS and AOA(highest of 3) < SW threshold?

[KRUSTY 34]

Power+Attitude=Performance.

Or am I being too simplistic?

[alexd10]

In this case UAS was an incident where no intervention was actually required, just keeping Normal Law in force. With 3 A/S data loss, but knowing that A/S cannot suddenly change on large scale without a considerable acceleration being sensed , with at least 2 principle different source of data for speed (GPS, and inertial – acceleration derived ) – results that ‘simple’ changes are ‘at hand’ to software engineers for preventing pilot to be suddenly put in the control loop, when at least a warning time would be much more appropriate if not even allowing temporarily discrepancies/anomalies to be surpassed (and I am curious, in how many similar cases the time for ‘appropriate reactions’ of pilots and return to the initial trajectory were larger than duration of speed anomalies) .... .

But – no changes for speed sensors, no changes for F/Ctl software, no changes in pilot training – how many years?

And these not thinking about other means possible to develop: wing load can easily be deducted measuring strain in wing structure (using tensiometric sensors f.e.), wing deflection can easily be measured also, the conclusion is that flight being nowadays a mass service, authorities, insurers, carriers (in a word the whole industry ) treat it more and more as volume,( not quality/safety) driven.

Unfortunately , as in many other trades, the lie stay in what is not told to customer (or rarely escaped, and with smallest font written) and even to industry professionals too. It seems that remain to judges to make that policy too expensive, (but, little hope too...)

[rudderrudderrat]

@ Old Carthusian,
A yoke moves - how far is a significant movement? Who decides the frame of reference?
The PNF's frame of reference is relative to his seat position just before the zoom climb. Significant movement is some inches before the yoke is in your chest - in your chest is excessive.

[CONF iture]

So how about: IAS >60 kCAS and AOA(highest of 3) < SW threshold?
I would not disagree.
Still, IMO, the single condition AOA(highest of 3) < SW threshold would be enough to satisfy the CS 25.207(c) you did mention.

A yoke moves - how far is a significant movement? Who decides the frame of reference?
It is not much who but rather what decides the frame of reference ?
Experience, experience does that. A student pilot is already able to appreciate that half travel displacement of the yoke is usual for takeoff or landing phases but unsuited for cruise speeds.

[infrequentflyer789]

For the record, and despite I doubt it would have changed the outcome in the light of the crew actions, I see two of them:
1/ the non-inhibition of the nose-up autotrim when stall warning is active
2/ the inhibition of the stall warning under 60kt IAS (even if I understand the logic behind the inhibition, I still think it may be worth reworking that bit of logic)

And perhaps a 3rd and 4th, but as I don't know the logic behind I'm not qualified to fully comment:
3/ the V/S switching source from air data to inertial (and back); it occured in AF447 and its consequence was a non-readable/unreliable/unrealistic displayed (air data sourced) V/S, while at the same time a reliable/realistic V/S value (aka inertial sourced V/S) was available (for the system).
4/ the non-inhibition of the F/Ds (by the system) when an UAS situation is detected: why? A/P & A/THR may (and have) been dropped, why not the F/Ds as they may give unreliable directions in such a situation?


I agree with those, with some caveats.

1/ Not sure about preventing upward trim only - you then turn THS into a control that can only ever ratchet nose-down which doesn't sound good. Maybe a fixed travel limit, but you'd need to ensure that the available range will give you all the control you need in the event you've got to a continued false stall warning. The whole autotrim area needs looking at in and out of stall IMO - too many incidents of autos trimming up into a stall and then handing the pilots the problem. It isn't going to be a simple problem with an easy answer though.

2/ I wouldn't be suprised if this was at very low level "close" to the senosrs and in hardware rather than software. Whether you term hardware issues "bugs" or not, it's a design issue (right down to what the AOA and pitot probes actually dleiver) that needs looking at.

4/ I think they do inhibit, may depend how you get into UAS though. But the switching in and out has got to be distracting and potentially confusing. Hence something with some real intelligence should switch it out and bring it back when things are properly understood and stable again. Now, what's the first UAS memory item again...


I'll also throw in another potential design issue, with the caveat that I'm also "not qualified to fully comment":

5/ the system notifies / warns of UAS, and changes control law etc., all well and good but where is that notification to the crew when the speed sensing is ok again ? I'm not sure there is anything (or nothing explicit) ? These pitot failures have been held up as transient events, lasting tens of seconds. They are being (mostly) correctly detected (but not prevented) by the built in checks and redundancy. But if the system never reports a return-to-normal, how is the crew to know ?

I believe this crew were still attempting to troubleshoot the UAS event well after it had passed, and when they should have been troubleshooting their real (correctly indicated) airspeed being fatally low.

[infrequentflyer789]

Power+Attitude=Performance.

Or am I being too simplistic?

And maybe they were trying that in the later stages. Doesn't work too well when stalled...

[Lyman]

320 has three degree -THS limit in Alternate. As above, it is stated that the 330 DOES NOT. That is an assumption based on the DFDR related to AF447. (THS migrating to Full NU and staying).

GOSPEL? Why indeed would the logic be changed? Wouldn't it be consistent in the family? I have read it here, but not in the words of programming experts.

Who has knowledge why the debut airframe would be different in AB NORMAL LAW/ALTERNATE2 than the A330?

As has been expressed here by others, AUTOTRIM in other than expected/normal conditions is considered unwelcome. What is the genesis of AL2 AUTOTRIM past 3 degrees (-)? Especially when mindful of the family DNA.

FALSE SW defeat notwithstanding?

[HazelNuts39]

the single condition AOA(highest of 3) < SW threshold would be enough to satisfy the CS 25.207(c)Not if the AoA gets the value zero for <60 kCAS.

[airtren]

There are two problems with that argument. Firstly, distance - at the distance in the cockpit the difference between audio and visual perception is so infinitesimal as to be totally disregardable. Understanding and interpretation are the key.

Firstly, I suspect your making the assumption that the visual information and sound information are of same duration, which is not correct.

The visual information duration needed is a fraction of a second.
The sound information duration is the time needed to pronounce the words, perceive the words, and transpose that mentally in a mental visual image of what that means - a couple, to perhaps several seconds.

That difference of a couple, to several seconds, is not infinitesimal in my math at all - particularly when the time to take actions is very limited, measured in seconds, or tens of seconds.


The second issue is that visual perception is worthless without a frame of reference and that is why a yoke is no more superior than a sidestick. A yoke moves - how far is a significant movement? Who decides the frame of reference?With direct visual contact, a move of the control beyond a certain position is sufficient to trigger a first visual warning.

After the first visual warning the observer can perform a closer observation, which can render more accurate information.
This is were my example of race car driving practice comes into play.

The visual observer is a pilot, so the visual frame of reference is developed during training, and developing awareness in the cockpit. Time needed is a lot less than duration of training.

Using visual contact does not mean excluding other means, those means, which you're suggesting. In fact I believe using all means is a current routine practice with controls were visual and tactile contact is possible.

Which brings forward, that adding the "tactile information channel" - remove (optionally, or not) the independence - is only a plus.

[Lyman]

With the greatest respect, OC, your argument has become centered on the relative appearance of Stick/Yoke. This difference is truly less important than the physical placement of the mechanism.

If the two Sticks were placed in proximity on the console, the argument is mooted.

It is the isolation of the mechanism, one from the other, that prevents a shared awareness of the positioning of the device, and the results commanded to the airframe.

Let's call this 'shared awareness' .....autonomic CRM.

2. "Of, or relating to, internal stimuli......." automatic.

Watching others is what Humans do best.

imho.

edit. Also, if RHS Stick went inop, and LHS was incapacitated, RHS could fly (also lefty) with #1 Stick. This would be a marked advantage even over the yoke system. Anyone suggest a place to put the trim wheels?

Coolie Hat? With Clacker?

To Sleepy:
(a request in re: DRAMA. Less, please?) The Earth has but one center.

[OK465]

If an air data problem or some other problem results in a reconfiguration to alternate law in an A330, I would think the 'plan' would then be to continue, under control, to point B without stopping off for stall practice. At point B, as the aircraft was slowed and configured, the autotrim would function just as it would in normal law and provide landing configuration trim settings compatible with airspeed. The 330 will fly the approach all the way to 'flare law' in alternate.

As for the 320, I thought someone posted a while back that from alternate law the 320 drops into direct law when the gear is lowered which would require manual trimming on the approach anyway. I may have hallucinated this but I would bet a 320 guy will correct this if I'm wrong (which is a definite possibility) within New York minutes. :)

Why they're different, I don't have a clue. And preferable, I guess, is in the eye of bestickenholder.

****************************************************

With respect to absolute separation of LHS & RHS control input devices:

In the case of a column/wheel 'jam' (possible cable/control surface jam) in a follow-up 'connected' yoke system, the older non-FBW Boeings had both fast and slow speed electrical trim switches for pitch control thru the stab with a jammed elevator or hand flown elevator control with a jammed stab. As far as roll, they had a force breakout shear system for the right side control wheel which allowed direct control of the spoiler mixer by the right-seater for roll.

The pilot actuated electric trim (no pilot actuated electric slow speed trim in the 73) is obviously carried on in later Boeings but I don't know about the shear-out capability for the control wheel, but I would suspect there is a provision for independent roll control of some sort. Could be wrong of course. :}

[DozyWannabe]

OK, one more on this subject, then if you want to talk to me about this it's going to have to be via PM (don't want to derail the thread further)

Whatever the extend of the ring was, the idiotic message went around, and it seems that nobody alerted the Moderator to delegate the impersonation problem to him.

Not so idiotic if you bear in mind the situation at the time, and I figured that if the mods had to be involved then the people giving me a heads-up would be doing so themselves.

But to help with your implying of unawareness of what was going on regarding your post, I will remind you that you were cc-ed on my communication to the moderator, so you were well aware of the link between your post, my reaction, my request to the moderator, and the removing of your post, so had plenty of info of why your post was removed.

And I heard nothing from the moderator other than noticing in passing that the post, along with a number of others, had been removed.

Nevertheless you continued recently in two instances, with repeating the spreading of context of the older idiotic messages...

Am I not permitted to be only partially convinced? It may be a coincidence, but your language skills seem to go to pot in similar ways when you get agitated.

This is so ridiculously amateurish ...

Do you need me to teach you how to act like a computer professional?

If you don't have access to the IP addresses, the Moderator does, and if he doesn't, the WEB master does, and so you should have asked the Moderator to look into it, if you had a suspicion, and wait for their answer, before posting publicly content of idiotic PMs...

Look, I've been posting on forums of all kinds for 15 years. As much as I have a high regard for this place, sorting out interpersonal spats and catching sockpuppeting is considerably low on my list of priorities - if the mod team take an interest, or if someone wants to get the mod team involved, that's down to them. Also, being a netizen (eurgh) that could be considered somewhat "old-school" I remember the days when this sort of thing was sorted out between users without resorting to "telling teacher". In most cases, the mod teams are busy sorting out obvious trolling and deliberate manure-blending and don't need to be bothered about a bunch of people who've got the wrong end of the stick about something.

As for "amateurish", when I'm getting paid for something, you have my undivided attention and will receive my best efforts. When I'm taking part in a conversation in my down-time it's my own damn business how involved I want to get. If I have reason to suspect I'm being played, I take that as an insult and tend to respond accordingly

Right - let's get on-topic.

I have asked you a clarification on your mentioning of the Airbus design problem with the pitot tubes, and you have not provided that yet. That's not even a new question like you've asked.

I can't find it using the search function. Apologies if it sounds rude, but would you care to repeat the question?

Anyway - a couple of minor corrections:

An algorithm is simply a set of instructions followed to take data in, perform an operation with it, and pass data out - these are the basic "bricks" of software. A program tends to consist of a collection of algorithms that perform a specific task, and would be a "wall", to continue the construction analogy. A system in software terms is a collection of programs that together perform the tasks required by the end user, so these would be a "building". Requirements are gathered from end users (in this case pilots, aero engineers and airlines). Specification tends to happen from the top down, based on those requirements, so you'd start with a system specification, break that down into the program modules required, and then each program module is broken down into the required algorithms. The A320 project was probably the most exhaustively specified software project of it's kind at the time, and I should know because I've seen examples! The algorithms themselves were deliberately designed with as few lines of code as possible to keep the implementation simple, and where the heavy intellectual lifting was required was using and combining those simple algorithms to meet the specification.

Implementation in this case involved the low-level algorithms being coded as per usual (albeit tested at a level several orders of magnitude higher than even the average safety-critical project), but rather than "hand-stitch" them together (and potentially introduce errors), the software team developed a graphical logic-tree builder to build the systems up. The individual modules were then exhaustively tested, and then each system was exhaustively tested by feeding them flight data captured from existing aircraft and also data outside the specified limits of operation in order to make sure that no logical errors had crept in. They then performed regression testing, which basically bombards the software with a lifetime's worth of flight data over the course of a few days and studied the output to see if there were any issues, fixing accordingly. This testing and refinement process alone went on for almost a year, if I recall correctly.

No system is perfect, but this one had to fall in line with aviation certification requirements, and as such the chances of failure had to fit an infinitessimally small number.

So that's a slightly off-topic ramble out of the way, just to drive home that anything that comes out of this regarding stall warning or anything else relates to the original requirements and specification, not the design or implementation.

CONF - the "IMO" regarding yokes pleases me greatly, and makes all the difference to how I read what you're saying.

Firstly, I suspect your making the assumption that the visual information and sound information are of same duration, which is not correct.

The visual information duration needed is a fraction of a second.
The sound information duration is the time needed to pronounce the words, perceive the words, and transpose that mentally in a mental visual image of what that means - a couple, to perhaps several seconds.

That difference of a couple, to several seconds, is not infinitesimal in my math at all - particularly when the time to take actions is very limited, measured in seconds, or tens of seconds.

That's fine theoretically, but realistically would you grab the control column or stick from your colleague without first verifying what is going on? Except in the extremest of circumstances I can't imagine that being the case. Whether you see/feel movement in a fraction of a second or a second or two via the instruments, would it not be prudent to first find out why they're doing what they appear to be doing?

While the difference may not be infinitesimal taken in isolation, in this case the zoom climb lasted for approxmately a minute before the aircraft stalled and began to descend, which gives, based on your numbers plus, say 10 seconds to confirm, at least 45 seconds to take control and perform corrective action before the aircraft stalls, and at a conservative estimate another 45 seconds while the aircraft is stalled to begin effecting a recovery before it passes through 30,000ft on the way down.

[chrisN]

A question – to ATPLs. Particularly AB drivers and AB330 especially.

The PF’s actions to try to correct roll were described as “stirring mayonnaise” and PNF advised him to be more gentle.

If the control had been a yoke, is it likely that such extreme movements would have been made by PF?

(My experience in a glider is that one can rapidly move the stick all over the place and the glider attitude is unchanged. Hold it slightly off centre, however, and it does change the attitude. But all that, of course, is at a low mach number. I would not do it at VNE! But also, gliders do not have “protections” built in.)

Chris N (Still no agenda, still just learning.)

[Organfreak]

That's fine theoretically, but realistically would you grab the control column or stick from your colleague without first verifying what is going on?

Not that you were addressing me, but yes...in a heartbeat!

Except in the extremest of circumstances I can't imagine that being the case.

I wonder, what could be more extreme than, "you are about to die!"? :eek:

By way of further explanation, this would be no time to be, er, polite.

[Neptunus Rex]

Quote:
Originally Posted by KRUSTY 34 http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/buttons/viewpost.gif (http://www.pprune.org/tech-log/468394-af-447-thread-no-7-a-6.html#post6806526)
Power+Attitude=Performance.Or am I being too simplistic?"And maybe they were trying that in the later stages. Doesn't work too well when stalled..." (infrequentflyer789)
In this case, TOGA allied to 15°(or so) nose up attitude giving a massive sink rate? There can be but one conclusion, the aircraft is stalled. So, reduce the pitch attitude to unstall the wing!

Krusty is correct.

[DozyWannabe]

Not that you were addressing me, but yes...in a heartbeat!

You might want to think that through a bit. Remember that it's looking like instinctive manipulation of the controls without properly assessing the situation was what got them into this predicament in the first place.

I wonder, what could be more extreme than, "you are about to die!"? :eek:

By way of further explanation, this would be no time to be, er, polite.

OK - so... Whether you've responded to seeing the flight controls move, or unusual responses of the aircraft through the instruments at this point you know that something's up, but you don't know what or why. Even with a traditional yoke giving you feedback you're coming into the situation cold - you don't know what the aircraft was telling your colleague and you don't have a feel for what the aircraft is doing. By grabbing the controls with little or no warning you risk startling your colleague, which is in fact incredibly dangerous and you could end up "fighting" each other. One of the advantages to the sidestick system is that by holding the priority button you can "lock out" the other stick if you need to.

This is still bad airmanship however. At the start of the climb, through the point of stall until you have had descended through 30,000ft you are not "about to die" if you keep your head about you. During that period you've got 90 seconds at least to ascertain the situation and develop a response before you're in serious danger. Politeness is certainly optional, but clear communication, knowledge sharing and correct response is mandatory. "I have control" means just that - once the callout is made both pilots have to respect it, and if that means hands-on-lap for the non-handling pilot then so be it.

Bear in mind that Captain Burkill of BA038, for example, only had 30 seconds before they hit the ground, less than a third of the time between AF447 beginning the climb and passing down through 30,000ft. In that time he managed to ascertain that his F/O was handling the aircraft well - thus taking control would be a waste of time, evaluate all the options available to him to extend the glide and get them over the fence and antennas, decide that the best thing to do would be to reduce flaps to 25 and then execute that decision. These actions were validated by the AAIB officer involved, who said he'd have given him a negative writeup had he tried to take control.

NB : I'm not comparing the two incidents in terms of airmanship or successful recovery - I'm simply using it to demonstrate that by thinking logically and remaining calm, you can do a lot in a surprisingly short time.

[RetiredF4]

Dozywannabe
@Franzl, CONF:

The precise position of the stick is considerably less important than being able to work out that the stick is not where it should be. Once that is ascertained, then the only logical recourse is "I have control".




Quote DozyWannabe
That's fine theoretically, but realistically would you grab the control column or stick from your colleague without first verifying what is going on? Except in the extremest of circumstances I can't imagine that being the case. Whether you see/feel movement in a fraction of a second or a second or two via the instruments, would it not be prudent to first find out why they're doing what they appear to be doing?


Quote Dozywannabe
That's fine theoretically, but realistically would you grab the control column or stick from your colleague without first verifying what is going on?

Quote:
Originally Posted by Organfreak
Not that you were addressing me, but yes...in a heartbeat!

Quote Dozywannabe
You might want to think that through a bit. Remember that it's looking like instinctive manipulation of the controls without properly assessing the situation was what got them into this predicament in the first place.

Could you make up your mind?

In the first quote not knowing (seeing, recognizing) the action of the PF you recommend to take over control of the aircraft, and in the second quote being able to recognize (by whatever means) the wrong input now you want to start a discussion with the PF?

That any kind of takeover control should be verbally announced is self explanatory.

franzl

[DozyWannabe]

Franzl,

There's a world of difference between determining something is wrong and calmly and methodically taking over control (which is what I was talking about in your first quote) and taking the controls with little or no warning in the split-second it takes you to see the yoke in a place you don't want it to be (which you'll see is the case in your second quote if you follow the conversation through).

[RetiredF4]

Thank you, i see, it has to do with the special DW interpretation.

In the first quote we talked about AF447, and you recommended to take over control. The further quotes have their roots in this discussion. They are based on the assumption, that the decision to take over control (which did not happen) might have positively been influenced by the observation of the wrong SS input, hence take over of control might have happened.

But now you argue, that this observation might be not helpful, but hindering in the decision, as the observation of the wrong input and a following take over might be premature to the situation and has to be discussed before?

There are lot´s of decisions to be made within a second during a normal flight , and that would have been one of those.

You are trying to pull my leg again.

franzl

[Organfreak]

Doozy said,
There's a world of difference between determining something is wrong and calmly and methodically taking over control (which is what I was talking about in your first quote) and taking the controls with little or no warning in the split-second it takes you to see the yoke in a place you don't want it to be (which you'll see is the case in your second quote if you follow the conversation through).

...zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz zzzz.................

[DozyWannabe]

I'm not pulling anything, I assure you.

Whether you can see what your colleague is doing or not, the decision to take control is an important one, and whether to do so or not is something that you have to think through, even if it doesn't take long based on experience to make that decision.

(You know this - I don't need to say it. Or are you simply picking holes in what I'm saying because I've annoyed you for not sticking to talking about software?)

When we were discussing things earlier, we were talking about the AF447 accident sequence as we know it to have occurred, and I was of the opinion that the PNF had a better handle on the aircraft's situation and as such, should have felt empowered to take control.

What I'm discussing with Organfreak (like me, not a professional pilot) is the consequences of taking control and that - in general - it should not be a decision taken lightly and should certainly not be rushed into if you see the control column in a place you don't want it. Even if you decide to take control quickly, the procedure must be followed and the decision must be well-made. If I've understood him right, he thought that taking the wheel as soon as it is seen to be out of position was the right thing to do, with which I respectfully disagree.

@Organfreak - very mature... :rolleyes:

[Organfreak]

Dozy,
The indecisiveness and lack of definitive action on the part of PNF killed those people just as surely as did the (apparent-- I'm waiting for the final report) incompetence of the PF. Your arguments are pure obfuscation and, AFAIC, stem from a desperate need to be right, no matter what.

I was very impressed with your careful and sober-sided analysis of the software stuff, but as far as your insistence on what is really only subjective opinion, and the utter lack of respect for other pilot's differing opinions, makes me feel that the most appropriate response possible to all of your nonsense was, and still is:
zzzzzzzzzzzzzzzzzzzzzzzzzzzzz............................... ..
I have little doubt that almost everyone else's eyes are glazing over at your single-minded contrariness!
Other than that, have a great day! :)

[Lonewolf_50]

Dozy, the algorithm bug that has been discussed at some length is why, below 60 kts, stall warning is curtailed even if one is stalled and weight is off the main mounts and main mounts are retracted and stowed.

That would be an algorithm bug raised in this incident.

Not sure what else, other than the algorithm used in the AF training and currency policy, given what appears to be not one but two instrument scans that were behind the problem from early on in the problem. (Refer back to PJ2's varoius posts on how this ought to have played out if you like).

There also appears to be evidence of a CRM regime that leaves me scratching my head, which may also be an organizational algorithm/decision tree sequence that could use some tweaking.

Insofar as software algorithms ... the one cited in re SW makes no sense to me.

For Old Carthusian: "Old Carthusian may now realize that instruments don’t necessarily tell what the flight control inputs are"Instruments do precisely that because that is what they are designed to do.

With respect, not quite. *

Your instruments reflect the outcomes of flight control (primary and secondary), power, configuration, and environmental effects on the aircraft.

While this is mostly a reflection of flight control input (particularly in a constant power scenario) your instruments don't do what you say they do.

I've seen your later retraction, but would like to point out (for pilots it's obvious) to non pilot participants the issue of power/attitude/configuration ...
which is what the pitch and power chorus have been on about since June 01 2009 ...
and which is where some fundamental flying basics seem to have been forgotten in one particular cockpit. :uhoh:

Why?

I sure hope BEA comes up with a good answer.

* = FWIW, I first got my first instrument rating in 1982. That doesn't matter at this point. Instrument scans and performance on the controls tend to atrophy when not used with a certain frequeny. I'd as likely as not kill all souls on board if, this afternoon, I was forced to fly to mins in dodgy weather on instruments with crosswind limits at the edge ... unless I remembered to wave off when the approach got too hard to handle ... waveoff is Navy speak for "go around" of course. :cool:

Rust never sleeps, but I hear it can kill.

[CONF iture]

If I've understood him right, he thought that taking the wheel as soon as it is seen to be out of position was the right thing to do, with which I respectfully disagree.
OF is correct.
Sometimes, there is not a split second to lose.
In Hamburg if the PNF could have seen the inputs applied by the PF during the flare, he would have jumped on the controls, with immediate effect, and for the good of all.

Airbus A320 Lufthansa nearly crashed during crosswind approach - YouTube
v=ueJeC2pxxbM

[Lonewolf_50]

If I've understood him right, he thought that taking the wheel as soon as it is seen to be out of position was the right thing to do, with which I respectfully disagree.

Dozy, with respect, in some situations it is mandatory, and sooner rather than later. Entire curricula are devoted to such things in CRM training, multi place pilot training, and training as an instructor pilot.

Sometimes, just take it, fly the plane back into its performance zone, then talk about it after all is settled and you are back to straight and level, or back on the ground.

Other times, talk the other pilot back into the box.

It Depends Upon The Situation

I have done both. I have had a plane or two taken from me as well.

In a few of above cases, more than one life was saved.

Had some Real Close Calls in between.

[Lyman]

Not so fast. We do not know what exactly PF saw on his panel. Hence we do not know the stimulus response record. If it differed from PNF's screen, he may well have thought the PF's stickwork...odd. We do not know how the a/c was behaving, precisely, especially in relation to the instruments of BOTH pilots.

What we "see" are results derived from inertially driven and recorded data, NOT WHAT THE PILOTS SAW.

I believe the a/c was quite active out of autoflight, and absent decent instrumentation, the Pilots struggled from the beginning, and never caught up.

It is ASSUMED the PNF was the one with the picture, I submit that is not possible to know: it only seems so after the fact, and with data that was unavailable to either of them at the time.

Bottom line: The climb was commanded by the Computer, by definition. Giving the pilot what he asked? It seems that way, but think.......

Only if the pilot KNEW he was climbing does he seem 'incompetent'. If he was reacting to an attitude that did not reflect reality, and his PNF did not notice, he was controlling the a/c, period.

How did the a/c reacquire airdata? Did it? With 40-60 degrees of AoA? Rolling Right/Left through 80 degrees? Attitude from ISIS? Roll cues from ISIS?

Can anyone else put together the degree of UPSET on the way up that may have contributed to PF's falling waaay behind? I think there was plenty, in no way did he start from Straight, Level. And he had to start quickly.

[Lonewolf_50]

Lyman, the CRM issue is that pilot suffering instrument failure declares

"My instruments (instrument) are (is) AFU"

response is by the other pilot

"mine are OK, pass me the controls"

or something like

"you are left wing down, roll right, stop roll
"your nose is too high, lower nose, stop your nose there"

and such other verbal input commands to fly the aircraft back to straight and level flight. But then, PNF needs to have his instrument scan up and running to be helpful like that ...

What appears to have happened is that an assumption was made that some instruments were running amok, and PNF switching to a differernt gyro feed would resolve that problem. But as not much was verbalized beyond that, I remain uncertain what PF saw on his displays.


I think we've talked about this before ... :cool:

[DozyWannabe]

Dozy, the algorithm bug that has been discussed at some length is why, below 60 kts, stall warning is curtailed even if one is stalled and weight is off the main mounts and main mounts are retracted and stowed.

That would be an algorithm bug raised in this incident.

I know it sounds like I'm being pedantic, but this is not an "algorithm bug", it is a specification that, with hindsight, needs revisiting. I suspect that if you dig into the design, it is not that stall warning is intended to be curtailed under those circumstances, it is because the sensors that provide the data cannot be considered reliable below that airspeed, and so the data as a whole is discarded until the circumstances make the data valid again (which is borne out by the return of stall warning as the speed picked up). The best and simplest solution I can think of is therefore to latch the current stall warning state when the data becomes invalid, and unlatch it when it becomes valid again.

@Organfreak - it's got nothing to do with being right, it's to do with the fact that left to their own devices we'd have "yokes r teh awesoem, sidesticks drool" from the same four or five posters over and over again with no dissenting opinion. I respect pilots greatly, but it doesn't mean that they're always right, nor does it mean that one should genuflect before them by rote.

@CONF - Or you could have had a split elevator condition (as in EgyptAir990) and a nasty crash.

[Lyman]

LW. With respect, the discussion of instrumentaion comes up in the CVR, clearly, and neither one claims AFU. PNF, "lost speeds, ALTERNATE LAW".

"Je ne comprends rien". "I understand nothing". That is not, "my dash is AFU".

Then, "We've lost all indications." WE, not ME. It has NOT been discussed, to my knowledge. Neither pilot made the distinction to which you allude. It is for this reason I am concluding neither pilot requested hand off to the other. Later, this changes. I too am not sure what PF saw, and no one can be. The communication was restricted to adversarial critique, and lacked team work, I'll say that. But change controls?

CRM issues are critical here, but I am reluctant to grant them causative weight. I believe the a/c was UPSET, responding erratically (via instrumentation), and there is no reason to believe the PNF had a better shot. EXCEPT in retrospect.

There was a cadence in that cockpit that resists the panacea offered by those here who think they have the picture; they do not. I am at a loss to define one single cue/comment that was absolutely bankable re: recovery post A/P loss.

[RetiredF4]

Dozywannabe
(You know this - I don't need to say it. Or are you simply picking holes in what I'm saying because I've annoyed you for not sticking to talking about software?)

My jumping into an ongoing discussion with you or with other posters is to comment on incorrect and misleading statements in an area i feel familiar and competent with.
As you recognize yourself that may happen with you more often when you are making statements outside your primary area of knowledge and expierience.

franzl

[DozyWannabe]

In a few of above cases, more than one life was saved.

Had some Real Close Calls in between.

On the line or when training? During training then of course the situation is different (and as an aside I'd never consider independent sidesticks to be a good idea in a PPL trainer), however on the line with SLF behind you, isn't it better to be absolutely sure (even if to be sure takes only a fraction of a second)? I can't help but think that if it were me and I'd just taken control, misread the situation and caused a crash I'd be absolutely gutted.

[RetiredF4]

I can't help but think that if it were me and I'd just taken control, misread the situation and caused a crash I'd be absolutely gutted.

So would you feel better, if you are being crashed because taking too long to come to a decision?

Pilots sit in the front end to make those decisions and act upon them. They are paid to be prepared and act.

franzl

[Organfreak]

Dozy--
The best and simplest solution I can think of is therefore to latch the current stall warning state when the data becomes invalid, and unlatch it when it becomes valid again.


OK, don't call it an "algorithm bug," call it a "specification," who really cares(?), BUT, otherwise, it appears that everyone who has weighed-in on this shortcoming appears to agree! How 'bout THAT??? In speculation mode, it is possible that the designers/programmers never foresaw this scenario. Ya can't think of everything, after all (until it happens).

There's no doubt in my "mind,", albeit no proof, that the on-and-off behavior of the SW did not help the pilot's understanding of the sitch.

Now.
@Organfreak - it's got nothing to do with being right, it's to do with the fact that left to their own devices we'd have "yokes r teh awesoem, sidesticks drool" from the same four or five posters over and over again with no dissenting opinion. I respect pilots greatly, but it doesn't mean that they're always right, nor does it mean that one should genuflect before them by rote.


I'd be the last one to genuflect, although I have tremendous respect for ATPLs in general. OK, say you're right: it's the same old culprits (I wouldn't know). Consider this: again, I have no flying experience and no axe to grind, but I came blowing in here out of the blue, and immediately and independently saw the sense of the yokes argument. Again, no proof, but what those in favor have said makes eminent sense to me, and does not appear to be the mindless, drooling AB criticism that you pretend it to be. That's not nice. Some of the reasoning has been quite sophisticated and well thought-out. Seems that you can't acknowledge that.

OK, OK, public disclosure: I do live in Boeing Country, but I have plenty of problems with them, too, especially after they basically let MD take them over in a management coup. Mostly, all Boeing has done for ME is to keep me awake at night with their incessant engine testing. But I digress. [where's the dang belly-laugh icon???]

[Old Carthusian]

AirTren
No that isn't my thought at all. Perception works differently for different people and some actually process audio signals quicker than visual signals. We don't know that this was the case in this situation but it is an important factor that has to be born in mind. Furthermore you don't transform an audio signal into a visual signal unless that is what you want to do. This is a fallacy - sound is sound and is interpreted as such.
The big factor missing from the discussion is interpretation. If we take a direct signal and interpret it or misinterpret it, it takes time to correct and re-evaluate. In certain circumstances an audio signal is more reliable but as we know that also is subject to interpretation. The point is that using your instruments for example, instead of a yoke provides you with an organised initial frame of reference with graduated levels. Glancing at a yoke and trying to decide where it is when you are suffering say spatial disorientation can be remarkably misleading. What you see and what you think you see can be two different things - the banana experiment is very relevant here. A calm person will see something different to a panicking person.
Looking at your instruments will provide you with a much better indicator and what is more it will aid your interpretation because the initial frame of reference is already set - you don't have to judge to the same extent and importantly to create a frame of reference in which to judge. Evidence from the CVR indicates that the PNF was quite able to judge the situation as was the Captain (initially) but neither took the physical action necessary to override the PF.
This is also another reason why the yoke is a red herring - given the ineffective intervention by both non-flying members of the crew it is highly unlikely that their behaviour would have been any different had the aircraft been equipped with yokes. Short of direct physical intervention it seems that nothing was going to divert the PF from his actions but we must also factor in that incomprehension of the whole flight crew. I hold no brief for the side stick or the yoke but in this situation the type of input device is irrelevant.

[Lyman]

"The type of input device is irrelevant..."

Erm, ok. What about its location?

What Instrument was the Captain seeing when he advised the PF to "Climb, Climb..." The PF responded, "But I have been climbing for some while...."

Thoughts? Any?

[DozyWannabe]

Subtle changes in terms of words, but major changes in terms of meaning. The exchange was actually:

02:13:39 - PNF : Climb climb climb climb
02:13:40 - PF : But I’ve been at maxi nose-up for a while
02:13:40 - CDB : No no no don’t climb
02:13:40 - PNF : So go down


It was the PNF that was saying "climb", immediately followed by a bunch of DUAL INPUT warnings. I think the Captain suddenly realised what had happened at this point.

[Lyman]

Thanks, Dozy. So it was the two with you know, screens who could not decide what to do? PNF says CLIMB, (What was he looking at?), and the PF had already been "Climbing"?

Do you see a problem with what they both may have been seeing on the instrumentation? What was telling them to input Nose UP? Rather than a solution, Captain insists, "NO, No Climb." NOT, "DO THIS..." Instead, a command to do nothing.

They were all three privy to the only ticket home, the instruments.

How long had the a/c been so confused? YES, the a/c. The pilots and Captain are screaming that, they had NOTHING to go on of any value, OBVIOUSLY.

Three pilots in the weeds, but you say the a/c was "Doing as it was programmed...." How do you reconcile this?

A/C? "Nothing wrong, just three confused pilots". You kidding me?

[jcjeant]

Hi,

DW
When we were discussing things earlier, we were talking about the AF447 accident sequence as we know it to have occurred, and I was of the opinion that the PNF had a better handle on the aircraft's situation and as such, should have felt empowered to take control.DW
Subtle changes in terms of words, but major changes in terms of meaning. The exchange was actually:

Quote:
02:13:39 - PNF : Climb climb climb climb
02:13:40 - PF : But I’ve been at maxi nose-up for a while
02:13:40 - CDB : No no no don’t climb
02:13:40 - PNF : So go down
It was the PNF that was saying "climb", immediately followed by a bunch of DUAL INPUT warnings. I think the Captain suddenly realised what had happened at this point.
After that ..do you stay scotched on your first opinion (I was of the opinion that the PNF had a better handle on the aircraft's situation and as such, should have felt empowered to take control.) ?