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SaturnV
1st Jun 2011, 16:02
Yaw String, the crew went to SELCAL mode at 0135. After that time, they did not reply to several queries from ATLANTICO. They thus would have missed any communications between ATLANTICO and the LH ahead of them regarding its deviation on encountering the MCC.

Was it prudent behavior going to SELCAL mode flying into a SIGMET area, and after receiving the following from dispatch?

at 0 h 31 dispatch sent the following message:
“BONJOUR AF447
METEO EN ROUTE SAILOR :
o PHOTO SAT DE 0000Z : CONVECTION ZCIT SALPU/TASIL
o PREVI CAT : NIL
SLTS DISPATCH”,

The yet-to-be-released portion of the CVR may have the answer.

The PF had performed five rotations in the South America sector since arriving in the A330/A340 division in 2008, including one to Rio de Janeiro.

The PNF had performed 39 rotations on the South America sector since arriving in the A330/A340 division in 2002.

The Captain had carried out sixteen rotations in the South America sector since he arrived in the A330/A340 division in 2007.

The data released to date do not indicate how many rotations occurred during the different seasonal variations of ITCZ activity in the South Atlantic..

aguadalte
1st Jun 2011, 16:33
SaturnV:
Was it prudent behavior going to SELCAL mode flying into a SIGMET area, and after receiving the following from dispatch?

Quote:
at 0 h 31 dispatch sent the following message:
“BONJOUR AF447
METEO EN ROUTE SAILOR :
o PHOTO SAT DE 0000Z : CONVECTION ZCIT SALPU/TASIL
o PREVI CAT : NIL
SLTS DISPATCH”,

SELCAL mode is not a question of being prudent or not. Its a question of VHF comm range. When we go into SELCAL we normally keep the last VHF comm freq selected until loosing full contact with the previous ATC and then select 123.45 on VHF 1. (VHF 2 on 121.50).

wiggy
1st Jun 2011, 16:36
Was it prudent behavior going to SELCAL mode flying into a SIGMET area

Not sure I understand that comment Saturn - Are you suggesting they should have maintained a continuous listening watch on HF...?

I do agree with Yaw String - we all need to help each other via VHF on the Oceanic Sectors......

xcitation
1st Jun 2011, 17:01
SaturnV

Delta T, the Lufthansa at 350 that preceded AF447 by 20 minutes on UN873 deviated 10 NM to the west. The Iberia following AF447 by 12 minutes was at 370 and deviated by 30 NM to the east. AF459 (an A330-203) following the Iberia by 25 minutes deviated first by 20 NM to the west, and then 70 to 80 NM to the east of the track, and was given permission to climb to 370. Neither the Lufthansa or Iberia deviations would have significantly affected fuel consumption.
AF459 at the time of its deviation would have been unaware that various centers were trying to contact AF447. (DAKAR contacted AF459 at 0411 asking it to try and contact AF447.)

Thanks Saturn V for the data.

Some alarmingly uninformed questions about fuel by other posters. To clarify transport aircraft always carry contingency fuel for deviations. My assertion is that the flight before and the flight after had prior to departure filed a modified flight plan to deviate around the storm. In doing so they took on extra fuel in addition to the contingency fuel. Any talk about the head office refusing a Capt extra fuel is absurd.
It is remarkable that AF447 showed no signs of significant deviation up to the point of the incident. IMHO this implies they were unaware of the storm system at least until they were in it. Did they get the wrong pre flight weather or simply omit it?
I don't believe any transport pilot would choose to take a center line path through a large storm given advance notice and the ease of a deviation. Would not having known of the storm also tie in with the bewildering fact that the Capt took rest immediately before entering the storm. I would want to look at a transcript of the pre-flight briefing to see if the storm was mentioned. Relatively minor mistakes early on (e.g. pre-flight) can snowball events down the road.

Lemain
1st Jun 2011, 17:17
Relatively minor mistakes early on (e.g. pre-flight) can snowball events down the road.Gordon Vette was banging on about that.....few if any accidents/incidents occur due to one factor. They are invariably due to a number of factors, most of which would not, of themselves, cause anything remarkable to happen.

Lonewolf_50
1st Jun 2011, 17:36
Graybeard, in re "better" AoA indicators. I'll suggest to you that the US Navy has been using one "better" (actually, I doubt it's any better) from before I started flying which functions reilably at airspeeds below 60 knots. (There is one on the T-34C Trainer that works as you describe ... a weather vane in the horizontal plane. See also AoA probes on various Navy jets).

I don't think it's the probe that's the issue, but a software decision on signal processing. You could do what you need to (no stall chirp on the ground) with a WoW switch (already have one on the bird, yes?) without artificially clipping the AoA signal when in flight.

Your comments, sir?

Lonewolf_50
1st Jun 2011, 17:53
Von Jeinsen's motion is primarily based on the expert opinion of Gerhard Hüttig, a professor at the Institute of Aeronautics and Astronautics at the Technical University in Berlin.

Just over a year ago, Hüttig recreated the Air France crash in a flight simulator. In the course of the exercise, Hüttig noticed a strange anomaly in the plane's reaction once it goes into a stall. The trimmable horizontal stabilizer, a flap instrumental in keeping the plane on an even keel, automatically adjusted to push the nose of the plane skyward.

Hüttig, a former Airbus pilot himself, and other pilots present for the test were unable to push the nose of the airplane down and thereby escape the stall.

Note: absent FDR data, how did he recreate that crash??? :confused:

What is unknown to me is how well the sim replicates stall for that aircraft. A number of sage Airbus pilots, who have also taught in sims, have pointed out (in the Tech Log Discussions) thta lacking the data points from extended flight test, programming data points into the sim for stalled or other "outside the envelope" flight conditions is a bit of a guessing game. It can lead to negative training due to anomalies NOT present in the aircraft being experienced in training in the sim.

While Hüttig doubtless understands this, please consider the report on his findings to be provisional. See also that the champion for this position is an attorney involved in an action ... tread with care here.

A few other points.

Pattern is full made an important observation a few pages back about displayed speed. For an interval there (about a minute?), what is on the FDR may not be the airmass flow that the wings, rudder, the THS saw. So, what is on record for BEA to analyze has to account for "data" points that are known to be erroneous for some of the time before and after the upset.
Q: The stall warning discontinued when the speed was BELOW 60 Kts. How in blazes do you fly a large jet at 35000 ft at a speed of 60 Kts ??

As above, if it was indicated, and the indicators were dodgy (iced probes) at that point, 60 kts may not have been what the airfoil was experiencing.
Q: If the IAS gets down to 60 Kts and the wheels are not on the ground then the aircraft must be very badly stalled. Disabling the stall warning makes no sense.
This is not a feature, it is a bloody stupid design error.
Seems to me that way as well, see my previous response to Graybeard.
If the stall warning sounds all pilots are trained from PPL level to expect it to continue until the stall has been recovered. Stopping the horn while the aircraft is still stalled is dangerously misleading and IMHO is a major contributing factor in this accident.

It is subordinate to stalling in the first place, but yes, it seems to have been unhelpful at a critical time, for the pilots on the flight deck.
Good? Stall warning stops when the speeds are invalid?
Great system. If the AoA indicates the wing is stalled, it should keep going, regardless of the speed.

Agreed, silence it with a WoW switch, as you won't fly an AB330 under 60 knots too often. :)
Q: If you don't trust the PDF and all the magic, isn't this what the ISIS is for? Also, what were the engines doing at IDLE only 70 seconds or so after they commanded TOGA power?
They must have really been confused.

Agreed. With ISIS NOT having VSI, the back up may be missing a vital cue. (Or, I read my ten-year-old display diagrams incorrectly).

Thought for Flight Saftey: confusion looks to have begun early in the event, when the PF had the A/P off and ended up in a climb. That looks to me like a symptom of primary instrument scan breakdown. If, and I repeat IF, his attitude indicator (pitch and roll / artificial horizon) was working, it appears that PF made a transition while not using attitude indicator as primary scan. Since we don't know what PF was seeing, that is a provisional hypothesis, quite possibly wrong.
To all out there, if you think your airlines have trained their pilots sufficiently for the most complex failures you are sadly mistaken or kidding yourselves. In the corporate, commercial environment accidents like these are at best " acceptable " damage ( one in 10 million chance, or one in 100 million chance ratinale ). Anything you hear about safety from airline higher ups are nothing but posturing, outright lies and utter baloney.

Are we stupid, then? We train constantly for all sorts of situations... Or could here be a training deficiency?

If you have/were never trained in hand flying close to the ‘edges’ of an envelope (or even outside an envelope), or if you have never actually been hand flying close to the ‘outside’ of an envelope, chances are that you won’t even notice that you’re going out... Whilst thinking you’re ‘hanging in there’... And so far, so good...

I take your point, add to my provisional hypothesis, training/proficiency programs, and the Admiral's idea about working pilots out to test their limits. I wonder at the confidence the public have in airline companies doing what is right.

Given the generally successful departure and arrival rates, maybe the public is willing to accept the very, very small risk of this "imnperfect storm" of events creating a flying catastrophe.
Actually if you have time ( they didn't ) you can call up AOA in the CMC maintenance pages.
What is the point of that? AoA is a flight parameter, if not a primary instrument scan item in all flight regimes. How hard is it to make it readable as a cross check, or in the corner of one of the displays?

Just change the page and location the computer is sending it to.

If you have a warning "revert to manual trim" can you not also find some real estate for "AoA = XX.X? "

This does not seem hard, but actually it is. Figuring out where in a display package this goes is a non-trivial process, since there is X area for display and a lot of different information that pilots use or need.
Is it possible to get a stall warning when pulling out of a dive?
Yes. If your pitch rate is too fast, you can change your AoA too fast and either create a stall, or an accelerated stall, while pulling out of a dive.

The latter killed a colleague of mine a couple of decades ago.

ECAM_Actions
1st Jun 2011, 17:57
More questions: Doomed Flight AF 447: Questions Raised about Airbus Automated Control System - SPIEGEL ONLINE - News - International (http://www.spiegel.de/international/world/0,1518,765764,00.html)

EDIT: Bad info.

Lonewolf_50
1st Jun 2011, 18:03
ECAMS:

As I understand the FC diagrams, Alt Law has auto trim for elevators and THS, you go to manual trim in Direct law for the THS. If I am reading that wrong, please advise.

From the diagram, it appears to me that elevator trim may not be operating in Direct law, but I may be wrong on that.

Here are the words ... (from an out of date summary of A 330 systems)

Alternate Law
• No change for ground, take-off and flare mode compared to Normal Law.

Flight mode :
Pitch axis : as per Normal Law with limited pitch rate and gains depending on speed and CONF.
- Roll/yaw axes : Depending on failure :
1. The lateral control is similar to normal law (no positive spiral stability is introduced).
2. Characterized by a direct stick-to-roll surface relationship which is configuration dependent

• Protections :
- pitch attitude : lost
- high speed : replaced by static stability
- high angle of attack : replaced by static stability
(Vc prot. Law) + aural stall warning when α > α sw*
- low energy : lost
Direct Law
• No change for ground mode and take-off mode compared to Normal Law.
• Flight mode : Maintained down to the ground in all three axes, direct relationship between stick and elevator/roll control surfaces which is center of gravity and configuration dependent.
• All protections are lost
Conventional aural stall and overspeed warnings are provided as for Alternate Law.
• Main operational aspect :
- manual trimming through trim wheel.

ECAM_Actions
1st Jun 2011, 18:19
@Lonewolf: you are right. In ALTN LAW there is auto THS.

Low Speed Stability will attempt to pitch the nose down to maintain just above Vls, but the pilot *CAN* override this (maybe that is why the PF was pulling up - he was stopping the nose from dropping in the belief they were flying and the systems thought they weren't due to the low airspeed reading?).

Lonewolf_50
1st Jun 2011, 18:30
ECAM: this is the first time I have understood that feature of the system, Low Speed Stability.

Low Speed Stability will attempt to pitch the nose down to maintain just above Vls, but the pilot *CAN* override this (maybe that is why the PF was pulling up - he was stopping the nose from dropping in the belief they were flying and the systems thought they weren't due to the low airspeed reading?).

I'll post a link to your post in the Tech Log discussion, since I have yet to see this man-machine interface issue raised in the deluge of posts on that sub forum. It may have been mentioned, but not in the concise way you just did.

PF is in ALT Law, so hand flying, which means flying a bit by "feel" (is this right, AB drivers?)

I have flown conventional aircraft in out of trim conditions, so I think I know what "feel" might be in his hand, and induce a pitch up that it takes a bit of scan to realize is happening. This might explain that initial "zoom" at 7000 fpm and initial "correction" to about 700 fpm climb ... thanks for switching the light on for me. :)

jcjeant
1st Jun 2011, 18:44
Hi,

Yes. If your pitch rate is too fast, you can change your AoA too fast and either create a stall, or an accelerated stall, while pulling out of a dive. This ... ?

YouTube - ‪Spitfire Crash‬‏

SaturnV
1st Jun 2011, 18:51
Aquadalte,


At 1 h 31 min 44 s, the RECIFE controller gave it [AF447] the ATLANTICO HF frequencies: 6649 or 5565 kHz, then 6535 kHz after the TASIL point. The crew read back the three frequencies. Note: TASIL is on the boundary between the ATLANTICO and DAKAR Oceanic FIRs.

At 1 h 33 min 25 s, the crew contacted the ATLANTICO controller on the 6649 kHz frequency.

At 1 35 min 15 s, they informed the controller that they had passed the INTOL point at 1 h 33, at FL350. They announced the following estimates: SALPU at 1 h 48 then ORARO at 2. They also transmitted their SELCAL code: CPHQ.

At 1 h 35 min 26 s, the ATLANTICO controller coordinated flight AF447 with the DAKAR controller. At 1 35 min 32 s, the ATLANTICO controller transmitted the following items to the DAKAR controller: TASIL estimated at 2 h 20, FL350, Mach 0.82.

At 1 h 35 min 38 s, the ATLANTICO controller sent a SELCAL call.

At 1 h 35 min 43 s, the crew thanked the controller.

At 1 h 35 min 46 s, the controller asked them to maintain an altitude of FL350 and to give a TASIL estimate.

Between 1 h 35 min 53 s and 1 h 36 min 14 s, the ATLANTICO controller asked the crew three times for their estimated time passing the TASIL point. The crew did not answer.

[There was no further contact with the crew.]


The recent BEA note indicates that the PF briefed the PNF who had arrived at the cockpit that at some time before 1 h 59 min 32 s that logon with DAKAR had failed. (At least 21 minutes before estimated changeover from ATLANTICO to OCEANIC DAKAR which was at 2 h 20 at the TASIL waypoint.) LH507 (believed to be the flight with AMDAR) monitored 121.5 the entire flight and never heard any communication from AF447.

The PF also briefed the PNF at 2 h 00 that the ‘little bit of turbulence’ just experienced would be similar to what would be experienced ahead.

Tim Vasquez concludes, “Based on the soundings above, my conclusion is that the maximum cumulonimbus tops were 56,000 ft with an equilibrium level of 47,000 ft, representing the tops of most parts of the MCS except near the edges.”

So CVR transcripts of any conversation on what they were seeing on their radar displays will be interesting.

I'll leave it to others to comment on jumping ahead on a frequency change 21+ minutes before one arrives at the boundaries of the FIR.

SoaringTheSkies
1st Jun 2011, 19:03
xcitation

I seem to remember that the flight plan for AF447 did not list Paris as it`s final destination but something closer along the way (toulouse?) and Paris as an alternate. The logic, so it was said, would be that filing Paris would have left them with less than the allowed contingency fuel and that through this trick, they could safely go with the amount of fuel on board and decide closer to French shores to use the contingency fuel to go to Paris.
Can anyone confirm that that was the case? And if so, what would that say about their ability to deviate around the cell and still make it to Paris. A refuelling stop in Toulouse would certainly be an embarrassment.

rgbrock1
1st Jun 2011, 19:03
Speaking of Tim Vasquez: If you browse over to his web site you'll note that he has made some data modifications, today as a matter of fact, which uses some of the data supplied by BEA on 27 May.
As usual it makes for some very interesting reading.

However, and again using data provided by BEA, he corrlelates that data with weather data available at the time.

This is the new, updated, weather chart and the flight path of AF447:

http://www.weathergraphics.com/tim/af447/sat-goes-0145-ann.png

wiggy
1st Jun 2011, 19:13
Guys.... a little knowledge is a dangerous thing:

Saturn

that logon with DAKAR had failed. (At least 21 minutes before estimated changeover from ATLANTICO to OCEANIC DAKAR

I'll leave it to others to comment on jumping ahead on a frequency change 21+ minutes before one arrives at the boundaries of the FIR.

Why are you claiming they're "jumping ahead on a frequency"? They are talking about their datalink or CPDLC / ADS, not radios. That comment in the handover means that haven't yet got CPDLC logon with Dakar ATC (possibly because it's too early for Dakar to "accept" them). As far as HF frequencies are concerned they may well have still been on SELCAL watch on the Atlantico frequencies...the fact that Atlantico couldn't raise them could just mean they were in an area of poor HF reception.


ap08

The logic, so it was said, would be that filing Paris would have left them with less than the allowed contingency fuel and that through this trick, they could safely go with the amount of fuel on board and decide closer to French shores to use the contingency fuel to go to Paris.

I think capital punishment should be re-introduced in the judicial practice. The management of the airline that tolerates (encourages?) such tricks deserves no less.

It's called a reclearance operation....been done for years in Longhaul.....I plead guilty to doing this, as I guess do many of the grey haired Longhaulers here. It's no big deal as long as you don't reclear onwards beyond your enroute alternate without the fuel to do so.

sensor_validation
1st Jun 2011, 19:28
Hi there,

german news outlet "Der Spiegel" has an interesting story about a german aerospace engineer (Professor, that is...) who experienced some strange (disturbing) behaviour in the simulator. Read yourself (english version):

Air France*Catastrophe: Victims' Families Propose Grounding All*A330s - SPIEGEL ONLINE - News - International (http://www.spiegel.de/international/world/0,1518,766148,00.html)

Kind regards,
Peter

I'm not able to find details of his simulation a year ago online - I wonder if it includes the zoom-climb to FL380 ?

Did find in here picture of the Professor suggesting a position for the captain?

AirFrance.pps (http://xa.yimg.com/kq/groups/503128/1533640560/name/AirFrance.pps)

SoaringTheSkies
1st Jun 2011, 19:40
so if they filed for Toulouse, intending to go on to CDG, I assume that a deviation might have put them into a situation where they would end up having to refuel before getting to Paris?
could this have begun as a severe case of get-homeitis?

SaturnV
1st Jun 2011, 19:43
Wiggy, although it did not affect the flight, Brazilian ATC had omitted DAKAR from the AF447 flight plan. (Whether it affected the search is probably an open question at this point.)

At 1 h 46, the DAKAR controller asked the ATLANTICO controller for further information regarding flight AF447 since he had no flight plan. The ATLANTICO controller provided the following elements: A332, from SBGL to LFPG, SELCAL: CPHQ.

The DAKAR OCEANIC Regional Control Centre created the flight plan and activated it. {No time given for when this was done.] The result of this was to generate a virtual flight following the planned trajectory in the DAKAR FIR between TASIL and POMAT. There was no radio contact between AF447 and DAKAR, nor any ADS-C connection. The flight remained virtual.

At 2 h 47 min 00 s, the DAKAR controller coordinated flight AF447 by telephone (ATS/DS) with the SAL controller (Cape Verde) with the following information: passing the POMAT point (leaving the DAKAR FIR) estimated at 3 h 45, FL350, Mach 0.82.

At 2 h 48 min 07 s, the DAKAR controller told the SAL controller that flight AF447 had not yet established contact with him.

wiggy
1st Jun 2011, 19:54
could this have begun as a severe case of get-homeitis?

It could equally have been a pragmatic approach to getting out of GIG in the first place. I haven't seen the performance figures for the flight but they may not have been able to lift the planned payload and "full" GIG-CDG fuel out of GIG...they might have been able to carry fuel for GIG-CDG plus a little bit of extra, but not enough to give them the legal amount of contingency, or buffer fuel, needed at the start of the flight. One option would be to come back on a windier cooler day, another dump freight or passengers...:ooh: , another one would be to fill up as much as possible, file a plan for say GIG-TLS - which given the shorter track could then mean you have full legal contigency fuel for that sector, so all legal, above board, a recognised procedure and safe.

Once you approach TLS you look again at fuel on board and decide wether you have enough in tanks to overfly TLS and continue to CDG with legal reserves or wether you don't, in which case have to do a tech stop.

It's not a technique used as much these days as it was 20-30 years ago but it still has it's uses if you're short of performance, and it's perfectly legal, the critical thing is you don't press on beyond the en-route alternate without fuel to so so....sadly the crew of AF447 never got to make that decision.

SoaringTS...you beat me to it, Rgds.

oldchina
1st Jun 2011, 20:00
A weather deviation decided in time (not in a panic) costs peanuts in fuel. Cut that idea.

SoaringTheSkies
1st Jun 2011, 20:01
wiggy

I understand the idea and yes, it does make sense when you're streching it a bit. my question was: how long a deviation could they have made before TLS would have been their guaranteed next stop?

We've seen many cases where pride made people make bad decisions.

Tipsy Barossa
1st Jun 2011, 20:47
Looks like a lot of posters do not have a clue about CPDLC operations, hence the comments about jumping ahead on a frequency, no CPDLC log on yadda, yadda, yadda.

Agree with wiggy, a little knowledge is indeed a dangerous thing. With the data released in dribbles, I cannot help but think that we are all being led into posting things which will help interested parties to cover their arses.

We might be doing the dead crew members a great disservice in our rush to pontificate and show off " armchair " style our great flying skills and systems knowledge.:hmm:

JJFFC
1st Jun 2011, 21:04
There is no mystery.

1/ a pilot nose up
2/ he stalled his plane and didn't alert the captain nor did he communicate
3/ he didn't recognize his fault although his instruments gave him all the necessary information (the lack of speed data is a consequence of the stall not the cause)

That's all.
Pilots are here to pilot the planes that are given to them (OK : their opinion is welcome).

I play golf : every 3 month I need 3 hours of practicing my 3 iron to be able to do something with it.

To pilot is a sport : it needs training and training and training.

That's why there are captain and cadet. Champions and losers.

drkraft
1st Jun 2011, 21:21
Just as a caveat, I have read most but not all the approximately 1300 posts on this thread. I have yet to read anything concerning the “Thrust Lock Mode” of the autothrust system. If it’s been previously addressed bear with me. For continuities sake, I’m starting at square one of how the system is supposed to work. As for my background, I flew the A-330 for a year and a half as a Captain prior to my retirement (60th birthday) about 1 year ago.

The problem with the autothrust system being inop is the way they interface with the thrust levers. When autothrust is in use the thrust levers are selected to one of 4 detent positions (TOGA, FLX/MCT, CL and IDLE) and don't move even though the engines may be delivering different amounts of thrust to maintain the selected mach/airspeed number. During cruise, they are in the CL or climb detent and have a power range from idle to max climb thrust. CL is the detent the thrust levers stay in 99% of the time. It is used for climb, cruise, descent and approach. To manually control the thrust levers you need to take them out of the CL detent, match the EPR setting with the thrust levers (there is symbology on the engine instruments which show you the position of the thrust levers and the actual EPR setting so that you can match them up before you disconnect the autothrust system). This provides a smooth transition between manual and autothrust use (no power surge). When the autothrust system failed on AF447, the thrust levers were in the CL detent. There is a difference if the system is turned off manually or due to a system failure. If the autothrust system is turned off manually using the pushbutton's on the thrust levers, the system will go to the max power setting of the CL detent unless the thrust levers are manually set as previously described. If there is a system failure the autothrust system goes into the "Thrust Lock Mode" and freezes the engine power at whatever thrust was being developed at the time of the failure. Thrust lock indications are a MASTER CAUT light, an amber flashing ENG THRUST LOCKED and AUTOFLT A/THR OFF,THR LEVERS.......MOVE ECAM messages, a single chime, and a STATUS page message. The chime is repeated every 5 seconds until pilot corrective action is taken. As you can imagine, when you have multiple failures, there's a lot of blinking lights, chimes, bells, whistles and other distractions not to mention a rather long list of ECAM and STATUS messages on the screens. The important thing to remember here is unless you reference the engine instruments, you don't know at what power setting the engines were actually producing at the time of the failure. The autothrust system on the Bus is OK, but remember the thrust levers never move so you lose one of the subtle cues normally found in the cockpit of most other aircraft. The autothrust system is normally very aggressive in trying to meet the speed demands placed on it. By this I mean you can get very large reductions or additions to thrust in order for the system to meet target speeds/mach settings. They are even more sensitive when turbulence is encountered and I've seen large variations in thrust setting in an attempt by the system to maintain target speeds. If you’ve ever ridden in the back of the A-330 in turbulence you will definitely notice the power changes. You also have to remember that power changes at max operating altitudes are very sluggish and it takes time to regain the target speed especially if the speed is bouncing around rapidly. In the AF447 situation, the PF (pilot Flying) slowed the aircraft from .82 to .80 mach. During this time he also encountered increasing turbulence and within a minute or so lost his instrumentation, autopilot, and autothrust. Until BEA releases the Flight Data Recorder readings and we know at what thrust setting the thrust lock mode froze the power, we won't know to what extent the autothrust system was responsible for possibly contributing to this accident. I hope this gives you a better understanding of how the system is supposed to work.

Lonewolf_50
1st Jun 2011, 21:39
JJFFC:
1/ a pilot nose up
2/ he stalled his plane and didn't alert the captain nor did he communicate
3/ he didn't recognize his fault although his instruments gave him all the necessary information (the lack of speed data is a consequence of the stall not the cause)

Is it your position that the airspeed indicators did NOT react to ice on the pitot tubes?

I play golf : every 3 month I need 3 hours of practicing my 3 iron to be able to do something with it.
To pilot is a sport : it needs training and training and training.
That's why there are captain and cadet. Champions and losers.

I play golf as well, and still use my 3 iron. The 1 and 2 iron have been retired.

Yes, one needs practice to stay proficient.

JJFFC
1st Jun 2011, 22:05
Lonewolf_50 (http://www.pprune.org/members/307224-lonewolf_50)


JJFFC:
Quote:
1/ a pilot nose up
2/ he stalled his plane and didn't alert the captain nor did he communicate
3/ he didn't recognize his fault although his instruments gave him all the necessary information (the lack of speed data is a consequence of the stall not the cause)

Is it your position that the airspeed indicators did NOT react to ice on the pitot tubes? It is my opinion that after the plane had stalled, the pitot tubes didn't reacted to ice but to the stall and to the fact that the plane was really below 60 and inclined.

Maybe the AC disconnected because the Pitot tubes iced, but the BEA has never written this in this report : nobody knows why the AC disconnected.

Maybe the PF wanted to climb because of the weather (somebody already mentioned that in this topic).

Pininstauld
1st Jun 2011, 22:14
The plot unthickens.....
If there is any shred of truth in the above posts - i.e. filing for LFBO but intending LFPG (all above board and as per regs, one assumes) - then a marginal fuel mentality scenario for lack of adequate CB avoidance cannot be dismissed. I checked the BEA report again for RTOW vs MTOW.... ah, suddenly it starts to make sense. I still maintain pts 1 to 11 on p49 for what happened subsequently. Whatever law it was in, the scenariio holds. Commercial pressure vs airmanship leading up to it? We shall one day see....

Log22
1st Jun 2011, 22:27
If you look at the findings of crash AF358 a lack of training, missing procedures and improper judgement seem to be the case. Of course this was a different situation than AF447 but it might indicate a not perfect safety culture and lack of or improper training within the airline.

]Conclusions (Wikipedia) AF358
The TSB concluded in their final report that the pilots had missed cues that would have prompted them to review their decision to land.[33] In their report[14] the TSB cited that
Air France had no procedures related to distance required from thunderstorms during approaches and landings
After the autopilot had been disengaged, the pilot flying increased engine thrust in reaction to a decrease in airspeed and a perception that the aircraft was sinking (spatial disorientation). The power increase contributed to an increase in aircraft energy and the aircraft deviated above the flight path.
At 300*feet above ground level, the wind changed from a headwind to a tailwind.
While approaching the threshold, the aircraft entered an intense downpour and the forward visibility became severely reduced.
When the aircraft was near the threshold, the crew members committed to the landing and believed their go-around option no longer existed.
The pilot not flying did not make the standard callouts concerning the spoilers and thrust reversers during the landing roll. This contributed to the delay in the pilot flying selecting the thrust reversers.
There were no landing distances indicated on the operational flight plan for a contaminated runway condition at the Toronto / Lester B. Pearson International Airport.
The crew did not calculate the landing distance required for runway 24L despite aviation routine weather reports (METARs) calling for thunderstorms. The crew were not aware of the margin of error.
The topography at the end of the runway beyond the area and the end of Runway 24L contributed to aircraft damage and injuries to crew and passengers.

xcitation
1st Jun 2011, 22:34
drkraft

If there is a system failure the autothrust system goes into the "Thrust Lock Mode" and freezes the engine power at whatever thrust was being developed at the time of the failure. Thrust lock indications are a MASTER CAUT light, an amber flashing ENG THRUST LOCKED and AUTOFLT A/THR OFF,THR LEVERS.......MOVE ECAM messages, a single chime, and a STATUS page message. The chime is repeated every 5 seconds until pilot corrective action is taken.

You raise another good point. Having read up some more on TOGA thrust lock incidents I can see that this issue alone has led to pilot overload and overspeed in the A330.
A330 experienced an uncancelable toga lock thrust condition following a predictive windshear go around (http://www.37000feet.com/report/724468/A330-experienced-an-uncancelable-toga-lock-thrust-condition-following-a-predictive)
Are we reaching the point of over automation?

JJFFC
1st Jun 2011, 22:38
Log22 (http://www.pprune.org/members/359459-log22)
Posts: 1


]Conclusions (Wikipedia) AF358

After the autopilot had been disengaged, the pilot flying increased engine thrust in reaction to a decrease in airspeed and a perception that the aircraft was sinking (spatial disorientation).

Very interesting your mention of the "spatial disorientation"

PS : But for your "AF bashing" it is not necessary ; AF has not to prove it knows how to operate planes since the 1930' ; and the Paris - Rio route is one of the oldest !

xcitation
1st Jun 2011, 22:58
The AF447 flight plan on the Vasquez site clearly states destination is Charles De Gaul (LFPG). So we can debunk the Toulouse destination theory if that is a reliable facsimile.

Air France 447 - AFR447 - A detailed meteorological analysis - Satellite and weather data (http://www.weathergraphics.com/tim/af447/)

Graybeard
1st Jun 2011, 23:37
Lonewolf50 For Graybeard and about AoA Probes and indications
Graybeard, in re "better" AoA indicators. I'll suggest to you that the US Navy has been using one "better" (actually, I doubt it's any better) from before I started flying which functions reilably at airspeeds below 60 knots. (There is one on the T-34C Trainer that works as you describe ... a weather vane in the horizontal plane. See also AoA probes on various Navy jets).

I don't think it's the probe that's the issue, but a software decision on signal processing. You could do what you need to (no stall chirp on the ground) with a WoW switch (already have one on the bird, yes?) without artificially clipping the AoA signal when in flight.

Your comments, sir?


The real measure of AOA is degrees, not knots, of course, although everybody has been shouting for a Stall Warning below 60 knots, not a specific AOA.

I don't have the numbers, but it appears that onset of stall of the A330 at that MAC and flap is less than 20 degrees. The report shows AF447 achieved AOA in excess of 40 degrees, double the onset of stall. How much AOA does it need to measure, 90 degrees, 120 degrees? What's the point?

You have to balance Stall Warnings in extremely rare events with far more common nuisance stall warnings, in order to maintain confidence in the system. In fact there was no doubt a point in the zoom climb to stall that airspeed was near zero, and the AOA vanes would fall with gravity, probably showing a negative AOA.

aguadalte
2nd Jun 2011, 00:24
Saturn,
The recent BEA note indicates that the PF briefed the PNF who had arrived at the cockpit that at some time before 1 h 59 min 32 s that logon with DAKAR had failed. (At least 21 minutes before estimated changeover from ATLANTICO to OCEANIC DAKAR which was at 2 h 20 at the TASIL waypoint.) LH507 (believed to be the flight with AMDAR) monitored 121.5 the entire flight and never heard any communication from AF447.

So CVR transcripts of any conversation on what they were seeing on their radar displays will be interesting.

I'll leave it to others to comment on jumping ahead on a frequency change 21+ minutes before one arrives at the boundaries of the FIR.

SaturnV,
The notification from ATLANTICO to DAKAR, (contrary to what happens now), was not automatically done from one ATC to the other at that time, once the CPDLC/ADS FANS system was not fully operational at that time. According to FANS procedures, one should try to notify/(log-on) between 10 to 40 minutes before reaching the boundary. Further, there are normally two HF radios on A330's. Therefore, it was common practice to call DAKAR, at least 10 minutes before reaching the boundary on HF2, while maintaining a SELCAL watch with ATLANTICO on HF1.

But I'm with you. I'm very curious on what CVR transcripts may bring to light.

barit1
2nd Jun 2011, 00:31
Greybeard reminds us:

The AOA sensor is just a high priced vertical weathervane,

...but like the weathervane, shouldn't it too be statically balanced? And if so, why would it be unreliable below 60kt? :confused:

The balance weight would not need to be out in the airstream; it could be internal, behind the aircraft skin.

Just askin'.

Graybeard
2nd Jun 2011, 00:52
Every AOA sensor I've seen on ground has been full stop down (neg AOA), which indicates no static balance. Don't believe I've ever seen one in flight. :)

I don't know a lot about AOA vanes, which I why I asked for someone really knowledgeable to speak up. You can peruse pix on airliners.net to get a good sample.

Captain Fishy
2nd Jun 2011, 01:23
TheShadow:

Your prescience is unparalleled on this thread. We have only been provided with a sou-son of data but I believe you have nailed it. The THS situation was, I also believe, the lethal factor.

I thank you for your insights. As a current 330 pilot I will now be paying a lot more attention to its position. Especially if things ever get convoluted!

I wondered who you were. I see from a basic search you may be an ex-Viet chopper guy. How do you know about all this Airbus stuff? And especially in such detail? Please tell us more?

Your erudition is also commendable.

Please keep up this extraordinary work.

Razoray
2nd Jun 2011, 02:03
The aviation industry may have just found their spokesperson. Notice his emphasis on proper training and having AoA displayed . We should all be grateful he landed that plane safely on the Hudson and became a hero. It seems his time has come....

Sully: Training is key to avoiding air accidents - CBS News Video (http://www.cbsnews.com/video/watch/?id=7368019n&tag=related;photovideo)

MountainBear
2nd Jun 2011, 02:15
You have to balance Stall Warnings in extremely rare events with far more common nuisance stall warnings, in order to maintain confidence in the system.True. But where that balance point is located is a matter of opinion (i.e, professional judgement). People can and do disagree. We tend to fixate on the needs of the moment and forget there is two sides to the story. Then it just becomes a game of ping-pong where we respond to one crisis by going too far to the left and another crisis by going too far to the right. It seems to me that the better course of action over the long haul is to pick a point of balance, any point, and then train around it.

I'm not sympathetic to the cacophony that wants to tweak software systems in response to every accident. The human being with their hand on the stick has to bear some responsibility, as does the entire safety systems in the corporation. Who trained this crew? Who gave them their line checks? Who oversaw the sim sessions and designed the syllabuses. :uhoh:

Edit:

The aviation industry may have just found their spokesperson. Notice his emphasis on proper training and having AoA displayed . We should all be grateful he landed that plane safely on the Hudson and became a hero. It seems his time has come....

I think his time has been and gone. Everything he says sounds good in theory but he fails to mention the critical factor of money. Sims are not cheap, sim sessions are not cheap, practice lessons in the plane are not cheap. How much money is a society supposed to spend in order to save 200-300 lives. Naturally, if it's your life at stake you want them to spend a lot of money. But when it's the other guy, maybe not so much. Whether it is explicit or implicit there is always a cost/benefit analysis going on. Always.

tartare
2nd Jun 2011, 02:16
Gents,
a question - without intending to minimise the difficulty of dealing with a situation like this - espec when the EFIS appears to have been giving very confusing readings, in strong turbulence and a confused flight deck environment - and without intending to insult anyone's intelligence.
Does this model of Airbus have a standby analog artificial horizon on or near the centre of the panel as I have seen in some airliners?
In what would appear to have been a jetupset situation like this, could any experienced airline pilots viewing this thread comment on how feasible it would have been to simply set cruise power and then maintain a wings level, nose level attitude using an analog AH alone?
I know it's aviaition 101 if you go IMC in a light aircraft, but perhaps not in a heavy jet...

bearfoil
2nd Jun 2011, 02:29
Artificial Horizon is an available selection, at extra cost, and was not optioned by AF for this a/c, as I understand it. I think it occupies the LHS of panel, top and left in P1's scan.

thermostat
2nd Jun 2011, 03:54
Razoray,

Part of AVIATE means don't fly through CBs when you are close to the "coffin corner". Had they deviated, all this talk of this law and that law and how to handle a stall would not be taking place. That's the real cause of this crash, nothing else. If they were already close to the CC at 35,00 ft, think of what would happen when they went to 38,000 ft.

thermostat
2nd Jun 2011, 04:11
Soaring the Skies,

The embarrassment of making a fuel stop should never get in the way of safety. Divert if necessary then stop somewhere for fuel. That's the Captains prerogative. The Captain is totally responsible for the safety of the aircraft and it's contents. They could have stopped in the Canaries or Lisbon for fuel.

iceman50
2nd Jun 2011, 04:11
Tartare

The pressure side of the EFIS was giving erroneous information the ATTITUDE part of the PFD was still working so they had a large Artificial Horizon to enable attitude to be flown.

Bearfoil

They had a standby AH it is called the ISIS, basically a smaller version of the PFD.

tartare
2nd Jun 2011, 04:43
So - a hypothetical question - Bearing in mind the idiosyncrasies of swept wing aircraft in stalls... if such a jet is in a fully developed stall, applying power and then using the AH/EFIS to obtain a wings level, nose level attitude would arrest the stall?

Machinbird
2nd Jun 2011, 05:24
So - a hypothetical question - Bearing in mind the idiosyncrasies of swept wing aircraft in stalls... if such a jet is in a fully developed stall, applying power and then using the AH/EFIS to obtain a wings level, nose level attitude would arrest the stall? Not without a big afterburner.

Too much induced drag. Reduce AOA first, accelerate, and fly happily ever after.

Try to power out of it and everyone will be shaking their head at your airmanship as they attend the funeral.:{

Roseland
2nd Jun 2011, 05:29
xcitation:

The BEA Interim Report stated:

1.17.1.3 Preparation of flight AF447 on 31 May 2009
Preparation of the flight by the central flight study service
The flight was prepared between 15 h 28 and 18 h 59. Paris Orly was given as the alternate airport at destination. Given the estimated load of 37.8 t, the dossier included a main flight plan at a standard Mach of M 0.82 with an ETF at Bordeaux Mérignac with alternate at Toulouse Blagnac as well as two additional direct flight plans, one at Mach 0.82 and the other at a "slower Mach", i.e. M 0.81. A summary table of the loads offered enabled the crew to make the choice of the definitive flight plan from among these three options.

The full report is at http://www.bea.aero/docspa/2009/f-cp090601e1.en/pdf/f-cp090601e1.en.pdf

Roseland
2nd Jun 2011, 05:55
To have a design where blockage of the pitots not only loses airspeed data but also (because it now shows speed is less than 60kts regardless of the truth) disables the stall warning strikes me as unwise.

Roseland
2nd Jun 2011, 05:59
xcitation:

The BEA Interim Report stated:

1.17.1.3 Preparation of flight AF447 on 31 May 2009
Preparation of the flight by the central flight study service
The flight was prepared between 15 h 28 and 18 h 59. Paris Orly was given as the alternate airport at destination. Given the estimated load of 37.8 t, the dossier included a main flight plan at a standard Mach of M 0.82 with an ETF at Bordeaux Mérignac with alternate at Toulouse Blagnac as well as two additional direct flight plans, one at Mach 0.82 and the other at a "slower Mach", i.e. M 0.81. A summary table of the loads offered enabled the crew to make the choice of the definitive flight plan from among these three options.

The report is available at: http://www.bea.aero/docspa/2009/f-cp090601e1.en/pdf/f-cp090601e1.en.pdf

BRE
2nd Jun 2011, 06:30
Two questions I could not find the answer to in this thread (bear with me if I overlooked them):

1. auto-trim moved the THS to up 13° while the PF was pulling up -- was the auto-trim movement a consequence of the PF's pulling up?

2. would a full down sidestick have had the authority to overcome the full up THS later on?

opherben
2nd Jun 2011, 06:38
MountainBear wrote,"I think his time has been and gone. Everything he says sounds good in theory but he fails to mention the critical factor of money. Sims are not cheap, sim sessions are not cheap, practice lessons in the plane are not cheap. How much money is a society supposed to spend in order to save 200-300 lives. Naturally, if it's your life at stake you want them to spend a lot of money. But when it's the other guy, maybe not so much. Whether it is explicit or implicit there is always a cost/benefit analysis going on. Always. "
I beg to differ:
a. Sully landed on the Hudson with his USAF training and experience background dominating, not airline training.
b. The way for cost effective and inexpensive training starts with proper pilot selection, syllabus and training. My son following a few weeks in class then simulator sessions along one week, got his B737NG type rating and is now flying with that top notch airline. Contributors are, again: proper candidate selection, syllabus and training. Decision makers need to understand flight, airline management, and wrap-up this prohibitive cost bull.

Regarding who to spend money on, the study of ethics teaches us that the best way to get life quality is to pursue smart egotism, in which people benefit by donating private resources to their community.

jcjeant
2nd Jun 2011, 06:46
Hi,

Two questions I could not find the answer to in this thread (bear with me if I overlooked them):

1. auto-trim moved the THS to up 13° while the PF was pulling up -- was the auto-trim movement a consequence of the PF's pulling up?

2. would a full down sidestick have had the authority to overcome the full up THS later on? Those questions were already answered
It's YES for the 2 questions if the airplane was acting like it must be in alternate law
Pull up and the THS will go up
Pull down and the THS will go down

RansS9
2nd Jun 2011, 07:25
"You have to balance Stall Warnings in extremely rare events with far more common nuisance stall warnings, in order to maintain confidence in the system"

With an AOA probe/indicators system set up to alarm CONTINUOUSLY anytime AOA reaches predetermined level before critical AOA and BEYOND (...sorry sound like Buzz Lightyear) with the addition of a weight on wheels breaker.

Can you envisage any scenario which would lead to a "Nuisance stall warning"?


PS.-- One interesting post few pages back was from a captain who made the point that sometimes having an alarm going of continuously can detract from an individuals ability to deal with a problem. I suspect there is a balance that has to be struck and I suspect / hope that the engineers, psychologists, pilots involved in cockpit design have already thought it through.

Capt H Peacock
2nd Jun 2011, 07:51
I apologise in advance if this has been covered already, but in the absence of any trustworthy data, two buttons on the FMGC would have led them to the GPS altitude and groundspeed.

Used in conjunction with the unreliable airspeed drill, I could envisage a successful outcome to their predicament with a minimum of fuss.

On an antecedent note, don't mess with the ITCZ.

edga23
2nd Jun 2011, 08:28
As I remember, the Air Caraibes pilots used GPS altitude to confirm that they were in stable flight using the pitch + power settings

GerardC
2nd Jun 2011, 10:00
Concerning fuel on board. Please read BEA's report appendix 7 page 116/117.
http://www.bea.aero/docspa/2009/f-cp090601e1.en/pdf/f-cp090601e1.en.pdf
At T/O, they had :
- 900 kg EXTRA fuel over the minimum M .82 DIRECT flight plan to CDG (alternate ORY) ;
- 1.900 kg EXTRA fuel over the minimum M .81 DIRECT flight plan to CDG (alternate ORY) ;
- 2.000 kg extra fuel over the minimum M .82 "subject to RIF to CDG" ("ETF" in BEA's wording) flight plan to BOD (alternate TLS).

At any given time, if fuel becomes an issue, the crew can decide to fly at M .81 (iso M .82) or to land at LIS/BOD/NTE without too much "embarrassment".

Concerning ITCZ crossing. Please read Tim Vasquez conclusion :
Air France 447 - AFR447 - A detailed meteorological analysis - Satellite and weather data (http://www.weathergraphics.com/tim/af447/)
Air France Flight 447 crossed through an area of tropical showers and/or weak thunderstorms with weak to moderate updrafts and a high likelihood of turbulence. The flight penetrated one cell at about 0150 UTC and then entered a cluster of cells beginning at 0158 UTC. The suspected zone of strongest cells was reached at 0208 UTC, which corresponds with the beginning of a track deviation, and another cell appeared to be reached at 0210 UTC, which corresponded with the time of autopilot disconnect. The flight was suspected to be within areas of showers and precipitation up until the time of impact, and the descent below FL250 into the critical -10 to -20 deg C zone probably involved some degree of clear icing on control surfaces, though it is uncertain whether this affected recovery of the aircraft, especially due to the short accumulation time that would be involved.

Tropical storm complexes identical to or stronger than this one have probably been crossed hundreds or thousands of times over the years by other flights without serious incident, including ascents and descents through critical icing zones in tropical showers. My original conclusion from June 2011 is still unchanged: turbulence and possibly icing creating an initial problem that led to a failure cascade. Whether that final weak link was human or machine error is beyond my area of expertise and is best left for the experts at BEA.

If CB/turbulence was a factor, why did they start to deviate at 02:08 and not during the 01:50/02:08 period (when they went through an equally "bad" area according to figure 5b shown above) ?

Concerning captain behavior : he went to rest only 10 minutes before things went bad.
Who on earth would go to rest if the 160 Nm radar picture showed some "extra-ordinary" weather ahead :ugh:

RetiredF4
2nd Jun 2011, 11:27
Static Balance
Every AOA sensor I've seen on ground has been full stop down (neg AOA), which indicates no static balance. Don't believe I've ever seen one in flight.

I don't know a lot about AOA vanes, which I why I asked for someone really knowledgeable to speak up. You can peruse pix on airliners.net to get a good sample.


The F4 had an AOA probe without the need for balancing. During groundcheck we checked the free movement of the probe and it stayed where you put it.
AOA Probe (http://www.amtonline.com/article/photos/1224076190875_f4_03.jpg)

AOA value was displayed on the AOA gauge (http://aviation.watergeek.eu/images/f-4b/f-4-aoa.jpg). The AOA also triggered an aural AOA tone in the headset, starting with a low frequency low repetitive tone at 15 units (if i remember correctly), becoming a steady medium frequency tone when optimum AOA was reached for landig (19.2 AOA) increasing to a high repetitive high frequency tone when AOA limits where exceeded. That was our stall warning and nothing else was needed. AOA tone, at 50sec (Takeoff after wow, at 3:00 low approach, at 3:31 Fullstop landing

Advantage over the betty bitch thing is IMHO, that you are aware over the trend the AOA is developing, whether it is increasing or decreasing.

I´m not saying that this would be the ideal system, just to make a point that the balancing problem should not lead to shutting off any kind of stallwarning below a predetermined speed. The technology is available since 1960!

Xeque
2nd Jun 2011, 11:47
Further to jcjeart's response (#1302) can someone tell me why trim is automatically triggered by nose-up or nose-down side stick commands in an Airbus? When flying my C152 I might wind in a bit of trim to ease the control loads when establishing a lengthy climb or descent but it's my decision. Once I've trimmed the aircraft for level flight I usually leave it alone regardless of altitude changes.

jcjeant
2nd Jun 2011, 11:53
Hi,

Cause it's Airbus .. not Cessna ...
Can't more explain than this PDF

http://www.smartcockpit.com/data/pdfs/plane/airbus/A330/systems/A330-Flight_Controls.pdf

And this:
http://img402.imageshack.us/img402/8669/thsinfo.jpg

Xeque
2nd Jun 2011, 12:47
Many thanks. It will take me a while to read and assimilate :) Best wishes...

zoomlens
2nd Jun 2011, 12:55
Apologies if these are dumb questions or have been answered before:

The BEA statement is silent on several points, presumably in order not to apportion any blame before publication of the main report in due course. One such omission is discussion of the crew's awareness of the approaching bad weather, and whether to change course. They did know they were heading towards an an area of turbulence before the captain went on his break at 01.55, but they did not decide to deviate. Would the two co-pilots have any indication after that that the storm was particularly severe? Would they have the authority to change course without consulting the captain? Would they be reluctant (more than, say a BA or Lufthansa crew) to wake him and ask to change course? Would these discussions be answered by the CVR?

Mimpe
2nd Jun 2011, 13:02
THe Phantoms post a few pages back is a great summary. It sounds like a toxic mix of features that all came together in the worst possible way. The accident seems highly multi faceted, with a few major junctures to intervene ,all of which were missed. The thread has been immensely interesting. One of the most important investigations in aviation history.

Threats and errors not identified early ( aircraft design issues, flight execution) - altitude, weight, non deviation around significant dangerous weather , pitot failure, over complexity of automation and warnings ( including variation in flight Law,thrust automation, sensor and warning cut - ins and cut offs), likely significant deficiency in basic instrument scan/priorisation in the early phases of the emergency, spatial disorientation ( somatogravic- related to deceleration cues interpreted as nose down attitude), probable combined crew attention fixation AND distraction, cockpit design flaws ( sidesticks not visible to PNF, non linked controls) ,the least experienced PF the worst possible situation, non recognition of stall, seemingly simple problems with basic solutions interpreted in complex ways

Lots of little things snowballing . I only hope the final report pays full attention to every single one of the features of the accident - there appear to be so many contributing aspects.

JamesT73J
2nd Jun 2011, 13:06
Quick question - seeing as Alpha seems to be one of the most important metrics of flight, where an instrument is available is it not possible for it to become the measure for things like approach speeds? I.e. consider Vref crosscheck etc but set approach against desired AOA number. After all this will be consistent across weights etc. Seems it would greatly help awareness and pilot confidence in what the wings are doing.

Lonewolf_50
2nd Jun 2011, 13:42
If I may supplement what Retired F4 pointed out in re AoA indications in my response to Graybeard.
Graybeard
I don't know a lot about AOA vanes, which I why I asked for someone really knowledgeable to speak up I don't think I am that much more knowlegable, but I am familiar with them on some aircraft.
The real measure of AOA is degrees, not knots, of course, although everybody has been shouting for a Stall Warning below 60 knots, not a specific AOA.

Not really. They've been arguing that clipping the stall warning in flight at 60 knots makes no sense. I agree.

IIRC, AoA is displayed in units, but that may be aircraft specific. For the Navy Trainers I am familiar with, T-45 stalls somewhere between 29 and 30 units, the T-34 at about 26 units AoA. See also Retired F4 comments above.
I don't have the numbers, but it appears that onset of stall of the A330 at that MAC and flap is less than 20 degrees. OK
The report shows AF447 achieved AOA in excess of 40 degrees Roger
How much AOA does it need to measure, 90 degrees, 120 degrees? What's the point?
To the point of stall, and beyond, as your barnyard theme suggests: let it weathervane in the airflow as it will.
You have to balance Stall Warnings in extremely rare events with far more common nuisance stall warnings, in order to maintain confidence in the system.
Yes about noise and distraction, but I see no reason to have a stall warning on the ground. There is an arbitrary decision to pick an airspeed. There is no reason to curtail it.

When you are flying, stall is about the most important thing to know about and unscrew first, since if you are in a stall, you aren't flying so much as falling.

Of all warnings, that ought to have primacy, don't you think?

Stall warning is not just another damn light or noise.
In fact, there was no doubt a point in the zoom climb to stall that airspeed was near zero, and the AOA vanes would fall with gravity, probably showing a negative AOA.
I don't agree with your assumption there. Airspeed near zero has little evidence to support it, and would have required IMO a much higher nose attitude than what FDR indicates.

I see no reason to clip AoA input based on any airspeed. That was my point. The WoW (squat?) switch would take care of the issue of spurious warnings, would it not?

AoA tied to stall warning would thus be tied to aircraft in flight/off the ground, which is where you both want and need stall warnings. It remains independent of the airspeed indicating system, as it should.

@bearfoil: I do not understand what you said regarding artificial horizon not being optioned by AF a couple of pages ago. There is one for each Pilot's Flying display, and a back up in the ISIS suite of instrumentation. :confused:

Can you elaborate? :confused:

SaturnV
2nd Jun 2011, 13:43
GerardC.

We do not yet know what they saw on their radar display; that portion of the CVR where there may have been crew discussion of what was depicted on the display has not been publicly released.

We do know that a LH 744 preceding AF447 deviated by 10 NM, that an IB 340 at FL 370 and following by 12 minutes deviated by 30 NM, that an AF 330 following by 37 minutes initially deviated by 20 NM to the left of the track, and then 70 to 80 NM to the right of the track, and climbed from 350 to 370.

Vasquez estimates that the top of the Cb AF447 flew into was 56,000 feet. If a Cb of that size had been visible by daylight or moonlight, every pilot flying would avoid it.
____________________

I agree that possible fuel consumption resulting from a possible deviation was not a factor.

FMY8036
2nd Jun 2011, 14:06
1. auto-trim moved the THS to up 13° while the PF was pulling up -- was the auto-trim movement a consequence of the PF's pulling up?

2. would a full down sidestick have had the authority to overcome the full up THS later on?

Those questions were already answered
It's YES for the 2 questions if the airplane was acting like it must be in alternate law
Pull up and the THS will go up
Pull down and the THS will go down

In the A320 Perpignan crash it seems that the sidestick couldn't overcome the fully deflected THS. How did you find out that in this case the pilots still had pitch control authority?

The report mentioned pitch down orders and the THS didn't seem to have moved.

Any clue about the THS position on the Afriqiyah A330 crashed in Tripoli?

glhcarl
2nd Jun 2011, 15:02
Concerning captain behavior : he went to rest only 10 minutes before things went bad.
Who on earh would go to rest if the 160 Nm radar picture showed some "extra-ordinary" weather ahead :ugh:

But even after the auto-pilot/auto-throttles dropped off it took several calls to the captain to get him back in the flight station? So how bad could the turbulence have been?

willfly380
2nd Jun 2011, 15:12
Was the radar display on bright or was it left at full dim by mistake, hence maybe the 160/320 nm pic didnt show any Wx returns.These questions are difficult to answer.
When i was a senior F/O , I thought that i knew the radar like the back of my hand, only to relearn how to use it on my own as a captain.
There is [ in my opinion] some hesitation in deviating for Wx in many F/Os that i have worked with, Does not mean it applies to all.

fgrieu
2nd Jun 2011, 15:50
jcjeant wrote


Two questions I could not find the answer to in this thread (bear with me if I overlooked them):
1. auto-trim moved the THS to up 13° while the PF was pulling up -- was the auto-trim movement a consequence of the PF's pulling up?
2. would a full down sidestick have had the authority to overcome the full up THS later on?
Those questions were already answered
It's YES for the 2 questions if the airplane was acting like it must be in alternate law
Pull up and the THS will go up
Pull down and the THS will go down
The BEA report tell us that the THS remained at 13% nose up including during the nose down stick input that occured during the descent, before 10000 ft. Therefore one (at least) of the following must hold true:
- THS movement under alternate law is more complex than suggested above; e.g. delayed, and the nose down command was shorter;
- the THS moved slightly but the BEA report does not mention it;
- flight law was not alternate law; direct? abnormal? sub-variant of alternate?
- there was a trim malfunction (but it seems unlikely that the BEA report does not mention it at this stage, so I rule this one out)

Any authoritative source on exactly how the autotrim works in the various flight laws?

jcjeant
2nd Jun 2011, 16:05
Hi,

the nose down command was shorter;
- the THS moved slightly but the BEA report does not mention it;
- flight law was not alternate law; direct? abnormal? sub-variant of alternate?
- there was a trim malfunction (but it seems unlikely that the BEA report does not mention it at this stage, so I rule this one out)flight law was not alternate law; direct? abnormal? sub-variant of alternate?
Sorry but if what you tell is right .. the PNF is an idiot !
In the BEA report PNF announce "Alternate law"

- the THS moved slightly but the BEA report does not mention it;

THS moved slightly but BEA does not mention it ?Can you explain (if BEA not mention it) how you know it moved ?

We can happily continue to speculate for months :8... as the final report will maybe show next year ....

I can even speculate on the PF experience. ....
The PF experience as nothing to do with the accident .. it's not a reference.
Pilots on the Perpignan A320 XL crash had 7.000 hours and 5.500 hours on type ... :eek:
Teneriffe KLM B747 ... the best KLM pilot was PF :eek:

fgrieu
2nd Jun 2011, 16:10
Must read: both pages
Doomed Flight AF 447: Questions Raised about Airbus Automated Control System - SPIEGEL ONLINE - News - International (http://www.spiegel.de/international/world/0,1518,765764,00.html)

LYKA
2nd Jun 2011, 16:57
We don't know if the ND picture was normal - until we know the tilt setting on the WXR it's difficult to conclude anything, but, I think At the time the FCTM/FCOM says something like" CRZ ALT - set tilt "slightly" negatively down," if that's what actually was set they may have been over scanning and had a false picture. Over water ITCZ type flying needs aggressive down tilts and short ranges(80nm and 3.5 ish down tilt etc)

SMOC
2nd Jun 2011, 17:17
fgrieu, I think you'll find the A/C was in Alt Law 1 or 2 depending if it had concluded a ADR disagree or fault, either way the pitch control in Alt law 1 or 2 is the same, with normal THS movement dependent on the load factor command from the sidestick deflection.

Once the A/C exceeded 30 degrees AOA however the abnormal attitude would have kicked in remaining in ALT law however the THS auto trim would have stopped.

So the initial nose up inputs caused the THS to trim for the new commanded load factor from the sidestick deflection (full nose up at times) and frozen at 13 degrees probably when the AOA exceeded 30 degrees.

GlueBall
2nd Jun 2011, 17:24
The PF experience has nothing to do with the accident .. it's not a reference. . . . but it's a complete mystery as to why he would pull and hold back pressure on the stick, climb from FL350 to FL380, during multiple stall warnings. Elementary pilot instinct, learned from day ONE in flight school, should have reminded him to do just the opposite. :confused:

BOAC
2nd Jun 2011, 17:33
SMOC - have a look at #1242?

bearfoil
2nd Jun 2011, 17:43
Suggest a

"LAWS of TOULOUSE" become a sticky.

:ugh: ( Laws of "too loose"? )

Lonewolf_50
2nd Jun 2011, 17:46
BOAC, I read that article again, and it seems to be contradictory.

{AF 447} After stalling, the A330's angle of attack stayed above 35°. But while this exceeded the threshold for the abnormal attitude law, the flight control computers had already rejected all three air data reference units and all air data parameters owing to discrepancy in the airspeed measurements.

{My thought: does this mean that AoA greater than 30 deg does not trigger Abnormal Law, or that there are some more tie ins to the comparisons {summed inputs into the flight computer} requiring (valid?) airspeed input before that law is selected?}

Abnormal law could only have been triggered by an inertial upset, such as a 50° pitch-up or bank angle of more than 125°. "That never occurred," says French accident investigation agency Bureau d'Enquetes et d'Analyses.

The BEA is still attempting to explain why AF447's crew failed to rescue the aircraft after it climbed to 38,000ft and stalled. The pilot's control inputs were primarily nose-up, despite the stall condition.

There has been no indication that the aircraft switched into any other control law, other than alternate, during the accident - suggesting that auto-trim was available throughout the descent.

{skip a bit}

In its conclusions over the {Perpignan} accident the BEA highlighted the rarity of the need to trim manually, which created a "habit" of having auto-trim available made it "difficult to return to flying with manual trimming".

"One of the only circumstances in which a pilot can be confronted with the manual utilisation of the trim wheel is during simulator training," it said. "However, in this case, the exercises generally start in stabilised situations."

In the wake of the A320 accident, near Perpignan in November 2008, the BEA recommended that safety regulators and manufacturers work to improve training and techniques for approach-to-stall situations, to ensure control of an aircraft in the pitch axis.
That doesn't answer the mail for dealing with a stalled aircraft. From from a common sense perspective, in terms of operations, "do better at NOT stalling" it certainly makes sense as a training objective.

fizz57
2nd Jun 2011, 17:48
So auto-trim was still active throughout the stall and continued stick-down inputs, had they been applied, would have moved the THS down and thus aided the recovery?

@Lonewolf: my reading of this, and the BEA report, is that the AOA data is lumped together with other air data measurements and accepted or ignored together... either all or none. (thoughts... does this apply to altitude and ROC too?)

No abnormal law for the same reason as no stall warning.

Lemain
2nd Jun 2011, 17:49
fgrieu -- note that the expert is said to be an ex-airbus pilot. When listening to the testimony of experts who have had previous links with manufacturers or employers, one should be sure to check that there is no axe to grind. Even a small chip on a shoulder can cause a man to walk with a pronounced limp. Demanding the entire fleet to be grounded until the phenomenon is 'adequately explained' (to whom?) is a serious step that could financially cripple or even destroy the manufacturers, airlines and their employees.

BOAC
2nd Jun 2011, 18:02
Lonewolf - as we are plagued by two similar threads here, you should know I have queried this statement on the 'other'.

EDIT: Just seen your post!

aguadalte
2nd Jun 2011, 18:04
I completely agree with you Lemain!

Ian W
2nd Jun 2011, 18:15
BBC ON THIS DAY | 10 | 1954: Comet jet crashes with 35 on board (http://news.bbc.co.uk/onthisday/hi/dates/stories/january/10/newsid_2709000/2709957.stm)

Tinker at the edges until there is another crash into the sea? :uhoh:

bearfoil
2nd Jun 2011, 18:17
Lemain

Oh yeah. After BA038, there was a similar refrain. Two rollbacks, simultaneous on a twin. A somewhat more serious event than UAS?

UAL recalled its entire fleet, but supposedly, for a deferred item (firebottle #5 in the Hold), then released them to the line after the inspex. Huttig plus salt shaker, please. (Chip on shoulder equals "limp" priceless!)

fgrieu
2nd Jun 2011, 18:20
In answer to Lemain:

I am just trying to understand what happened, and what lessons can be learned. I did link to an article echoing a voice asking to ground the planes, but that's not an endorsement of that opinion.

If (that's far from evident, at least to me) the THS remained nose up 13° despite the pilot commanding a nose down circa 13000 ft due to a characteristic of the flight law then active, then I think pilots on the type should be trained to trim manually in order to get out of stall in that flight law, rather sooner than later. Anyway, if that's true, I expect many if not most pilots on the type have read the BEA report and came to that conclusion by themselves.

Full disclosure: I'm not a pilot, I am an engineer working on security (not safety) critical systems.

the_rizzle
2nd Jun 2011, 19:31
there is a lot of stuff left to cover by the BEA...... they have barely addressed the cockpit conversation, they have not addressed at all many of the ACARS messages that were sent during the last four minutes (PRIM1/SEC1 faults et al)

Kilda Ste Hilda
2nd Jun 2011, 20:01
I would say that in hindsight we all know that they should have stay clear of the ITCZ weather; well in that part of the world they could have deviated a hundred miles off course with no problem from ATC with respect to parallel airways.

However in the Atlantic or Pacific with closely spaced airways and random tracks, sometimes ATC is pretty slow or outright deny any request to deviate. I guess the junior crew members were reluctant to exercise the emegency option of deviating without clearance. Some airlines come down hard on pilots deviating without clearances.

You may say, ask for deviation clearance early, but with the modern flat plate weather radar system, severe weather returns sometimes only pop up within 40-60 miles ahead. ATC like Tokyo takes hours to reply or authorise deviations. How do you veterans deal with this situation........exercise your emergency contigency procedures and deviate without clearance and risk a TCAS event followed by loads of explaining to do?

SMOC
2nd Jun 2011, 20:35
BOAC, cheers, what are the odds, a failure allows the THS to still be used and unfortunately for whatever reason a significant nose down input is not made.

Perhaps Airbus should freeze the THS after an ADR failure and not wait until an abnormal attitude is reached leaving you with an A/C that is possibly trimmed just outside the range of a UA.

Lonewolf_50
2nd Jun 2011, 20:45
BOAC, cheers, what are the odds, a failure allows the THS to still be used and unfortunately for whatever reason a significant nose down input is not made.

Perhaps Airbus should freeze the THS after an ADR failure and not wait until an abnormal attitude is reached leaving you with an A/C that is possibly trimmed just outside the range of a UA. SMOC:
1. What do you mean by "freeze the THS": cancel or pre-empt all commands to move it, up or down, unless the pilot manipulates the trim wheel? :confused:

SMOC
2nd Jun 2011, 21:14
Stop auto trimming with an ADR problem, which would have left the trim at 3 degrees which was speed stable for FL350. Once the problem was resolved allow the auto trim to resume.

YorkshireTyke
2nd Jun 2011, 22:32
.......Look, if you haven't read much of the thread..........

Life's too short.

stepwilk
2nd Jun 2011, 22:42
At this point, 67 pages in, the thread is random noise.

bubbers44
3rd Jun 2011, 00:35
I agree stepwilk, too little known information was put out and who knows when any more will be known. Now all that is being discussed is the sliver of information they released. They have it all even though they haven't gone over it thoroughly but the CVR would tell a lot of the story. We can go on about why the PF elected to pull up and start the whole disaster but the CVR will explain why he thought he had to do it. They already have that information. Eventually we will know too. Guess we will have to wait. It sucks, doesn't it?

philipat
3rd Jun 2011, 02:41
As a side matter to that of course deviation, on the night in question, wouldn't FL 380 have been reserved for South bound traffic?

Motorola
3rd Jun 2011, 02:50
Does the A330 have inertial VSI?

It's not normally in my scan, but may have given them an indication that they were in a deep stall?

Jennie023
3rd Jun 2011, 04:11
Can anyone post the images of the given thread... :sad:

opherben
3rd Jun 2011, 04:58
stepwilk, bubbers44,
are you suggesting people shouldn't have the right to express whatever they think, or that none is valid?
No more information would reveal whatever we don't yet know, BEA released information along that line or it would be meaningless and misleading.
You don't need to know the color of cockpit inetrior if you know that the captain went to rest minutes before entering a CB other flights bypassed, that the PF held pro-stall controls throught the fall, and that it resulted as it did.
The answer as to why to me is also pretty obvious, it's in the previous sentence.
I wouldn't discount opinions of worthy others, just because so much was written, you don't have to read it all.

Good memories
3rd Jun 2011, 05:07
TheShadow in post 1222 gives the best analysis so far on the facts that are known to us. I advise everyone who has an honest and keen interest in this accident to keep a a good look out for his postings.

I go back to gardening, the fate of a retired pilot.

bubbers44
3rd Jun 2011, 05:28
BREATH, it helps. Getting old sucks.

dcasali
3rd Jun 2011, 05:47
Lonewolf_50

I noted that the Flightglobal article referenced in #1242 stating Abnormal Law was not entered was dated in January of this year, prior to recovery of the data recorder. I would guess it must be re-evaluated in light of the flight data now available. In Abnormal law I've read that only the manual trim wheel would alter the angle of the THS. I've also read that at 13 degrees nose up THS, the sidestick would not have authority to lower the nose. So this is a big and unresolved issue.

stepwilk
3rd Jun 2011, 06:10
are you suggesting people shouldn't have the right to express whatever they think, or that none is valid?

Not at all. It's just that 1/after over 1,350 posts, anybody coming relatively fresh to the subject simply hasn't the time to read them all, so the same questions get asked and theorizations get posted over and over and over. 2/The people who have been here from the beginning are no longer bringing anything new to the subject. 3/Many of the real, knowledgeaqble professionals--I'm certainly not one of them, but then I don't post on matters of true import--have moved on, realizing there's nothing new or important to say. And 4/Many of the professionals have been replaced by curious frequent flyers, model builders, flightsim players and Cessna 150 pilots.

Hence random noise. My rule of thumb is that when a thread begins to top five pages, it's time to move on. Everything important to say has been said.

SMOC
3rd Jun 2011, 06:44
I noted that the Flightglobal article referenced in #1242 stating Abnormal Law was not entered was dated in January of this year

decasali it's the 1st of June not Jan 6th, so apparently its from the recovered data.

philipat
3rd Jun 2011, 07:08
I go back to gardening, the fate of a retired pilot.


What is VR on the latest generation of mowers?!

TOTitan
3rd Jun 2011, 07:43
stepwilk

"Hence random noise. My rule of thumb is that when a thread begins to top five pages, it's time to move on. Everything important to say has been said."

So practice what you preach and move on, stepwik

Count Niemantznarr
3rd Jun 2011, 09:26
Indeed The Shadow a great post. Thank you.

However let's cut to the chase. Has anyone flown the AF scenario in the simulator and successfully brought the A330 out of its super stall? It is either possible or it isn't.

Now with the enlightenment that it is not just T tailed jets that can end up in this predicament, then some of the protections that are fitted to rear engined aircraft must be considered for other types. High speed, high altitude stall recovery must be trained for or preferably, a better awareness of what is causing an erroneous speed indication. If Air France knew there were issues with the Thales pitot tubes, it was allegedly grossly negligent that they did not either train for the situation the crew of AF 447 found themselves in, or accelerated the replacement of the defective parts.

Perhaps it is time to look at a safer design from the past. The VC10 is the only T-tailed airliner never to have been involved in a deep stall situation. The "10" had a very large and powerful tailplane which was mounted high and swept back. If a stall did occur the elevators were situated well aft from the wing blanking effect. The AF A-330 was lost from an altitude of 38,000 feet, but the VC10's were frequently flown at 43,000 feet with a little help from the droops. Other designs such as the Trident and 1-11 proved in testing to be irrecoverable in a deep stall without a tail chute.

I find it hard to believe that with all of its automated protective systems, this A330 was lost from such a high altitude in an apparently unrecoverable stall. Perhaps Boeing have got it right?

jcjeant
3rd Jun 2011, 09:50
Hi,

However let's cut to the chase. Has anyone flown the AF scenario in the simulator and successfully brought the A330 out of its super stall? It is either possible or it isn't.Unfortunately .. IMHO you can't reproduce this in the sim with realism.
On the other hand I suspect (after all the allegations in the press or experts about possible prob with Airbus procedures .. etc ..) that Airbus will make a real demonstration flight and introduce a loss of pitot ... and demonstrate that it was no problems for continue safely the flight.
They will save their ass

Zorin_75
3rd Jun 2011, 09:57
I find it hard to believe that with all of its automated protective systems, this A330 was lost from such a high altitude in an apparently unrecoverable stall. Perhaps Boeing have got it right?- The protections were not active
- To conclude it was unrecoverable we would need to know that there were efforts made suitable to recover it. We know of one ND input very late in the game the a/c seemed to be responsive to, but not how long it was sustained. In fact we have no information whatsoever about what happened the following 1m30s
- I can guarantee you it's possible to stall a Boeing. And by pulling up you're not likely to recover that one either

Count Niemantznarr
3rd Jun 2011, 10:00
Test pilot "Cats Eyes" Cunningham put a Trident into a deep stall and recovered.

I expect nothing less of AIRBUS and its A-330 test pilots.

The AF 447 crash has shown that in the certification process, there is a gaping hole.

lomapaseo
3rd Jun 2011, 10:42
"Hence random noise. My rule of thumb is that when a thread begins to top five pages, it's time to move on. Everything important to say has been said."

So practice what you preach and move on, stepwik

I suspect he has, just like many others. What he has stated is his individual opinion and some readers take that as meaningful that no significant revelations have been missed in their read of the forum.

Quite a few of us are waiting for some new facts rather than a rehash of what might have happened.

Rollleft
3rd Jun 2011, 12:02
After the pitot was blocked with ice it performed as an altimeter. It would direct the pilot in a counter intuitive and divergent fashion, stick back resulting in increasing indicated airspeed. Stick forward would indicate a speed decrease, so much so that the AOA was disabled.

This is the saddest story since Aero Peru.

HalloweenJack
3rd Jun 2011, 12:37
reply to Count Niemantznarr:

yes whilst in testing recovery by an experienced test pilot can be done but in practise a number of tridents and other aircraft have been lost in a `super stall`;

ASN Aircraft accident Hawker Siddeley HS-121 Trident 1C G-ARPY Felthorpe (http://aviation-safety.net/database/record.php?id=19660603-1)

ASN Aircraft accident Hawker Siddeley HS-121 Trident 1C G-ARPI Staines (http://aviation-safety.net/database/record.php?id=19720618-0)

ASN Aircraft accident Canadair CRJ100 (CL-600-2B19) C-FCRJ Byers, KS (http://aviation-safety.net/database/record.php?id=19930726-2)

Rananim
3rd Jun 2011, 12:40
I agree we've gone as far as we can with what we know.However,training issues havent really surfaced.Full stalls are trained in flight school.In airlines,only the approach to stall is trained and minimum altitude loss is always emphasized.This might lead to a dangerous mindset for newish pilots;the altitude loss is as important as recovery.Significant altitude loss is a dead cert at altitude.High altitude upset recovery also rarely trained.Other training issues that I can think of;crews anxiety over busting altitude when facing speed loss at altitude.Crews have been known to wait for ATC clearance before descending.Turn off airway and DESCEND IMMEDIATELY.The use of weather radar has been addressed but they knew there was weather up ahead.Tilt,gain and brightness control are possible traps.Captain's rest already discussed.

Combine the gaps in training with airline-endorsed automation reliance and the peculiarities of the Airbus and you have enough ammunition to establish a strong case for pilot error with strong and genuine mitigating circs.

aterpster
3rd Jun 2011, 14:15
Rananim:
Turn off airway and DESCEND IMMEDIATELY
In the case at hand the captain should have ordered that the nose be lowered 15-20 degrees nose down and he should have reached over and set cruise-descent power while telling the pilots to ignore airspeed indications.

Although the turn off airway is the ICAO method, in this case it could have resulted in increased disorientation. Wings level was critical until a safe, stable configuration was assured.

Jazz Hands
3rd Jun 2011, 15:28
The BEA report tell us that the THS remained at 13% nose up including during the nose down stick input


The Perpignan A320 report says something quite critical - the THS only moves once the elevators are driven beyond neutral.

It's not enough just to push the stick forward, the elevators have to go past the neutral setting.

I don't know if the A330 works the same way. But that would explain why the THS stayed put despite nose-down stick.

MRGTC
3rd Jun 2011, 17:13
Too much to read but if all else fails turn all ADIRS off. Make direct law happen and fly it like a cessna. Stick forward and centered. Fulll power. Wings level and recover. Otherwise 80%and 2.5 nose up. Airline industry no training for UAs or chamber (depress) runs. What a joke. Don't be near rec max (coffin corner). And go around the weather. 100 mm plus who gives a ****. ATC are advisory only. Do what you need too do. No one one on the ground will save you. You are the pilot. If not, get out of the cockpit and let the big bIg boys (well trained ie Sully) do it for you. The moral of the story is don't fly into thumderstorms! Any questions?
One hint Power plus Attitude equals performance. Descend and get some CLs

BEagle
3rd Jun 2011, 17:17
....but the VC10's were frequently flown at 43,000 feet with a little help from the droops....

Complete and utter nonsense, Count Numbnuts! The VC10 did not have 'droops', the maximum altitude for flying with slats/flaps extended was 20000ft. Flying with flap/slat at 20/OUT or even 14.5/OUT at such heights at flap limiting speed burns a colossal amount of fuel; it would NEVER have been an airline's policy.

I look forward to some sane comments once the report has been fully released. Meanwhile, I hope that pilots will be encouraged to learn more about their aeroplanes and systems rather than becoming dumbed-down auto flight system and ECAM monitors.

Aileron Drag
3rd Jun 2011, 17:36
Too much to read but if all else fails turn all ADIRS off. Make direct law happen and fly it like a cessna. Stick forward and centered. Fulll power. Wings level and recover. Otherwise 80%and 2.5 nose up. Airline industry no training for UAs or chamber (depress) runs. What a joke. Don't be near rec max (coffin corner). And go around the weather. 100 mm plus who gives a ****. ATC are advisory only. Do what you need too do. No one one on the ground will save you. You are the pilot. If not, get out of the cockpit and let the big bIg boys (well trained ie Sully) do it for you. The moral of the story is don't fly into thumderstorms! Any questions?

MRGTC.............

I agree with your solutions, but I would point out that civilian airline pilots trained in the 50s, 60s, 70s, and possibly 80s, were trained well. They had 'airmanship'.

I have flown with many ex-forces pilots who were bordering on useless. I think some of them had only kept their jobs because they were, in UK parlance, 'civil servants'.

Please don't presume to be superior - you (possibly) are not.:)

Lonewolf_50
3rd Jun 2011, 18:12
Hi, MRGTC, I got my training in the military. If I may ...
Too much to read but if all else fails turn all ADIRS off.
Considering that they were night, IFR, turning off the ADIRS turns off the attitude reference system. Not so sharp to get rid of the attitude indicator in night IFR flying in bad weather. Deliberate partial panel with 200 pax aboard is below average headwork, don't you think? Also, you might note that the back up instrument panel doesn't have a VSI. I'd leave them fancy electric flight instruments on.
Make direct law happen and fly it like a cessna.
It isn't one. Ya don't fly a Phantom like a C-130 either.
Stick forward and centered. Full power. Wings level and recover.
Otherwise 80%and 2.5 nose up.
You talking about stall recovery or stall prevention?

If stalled, nose up and power may or may not get me out of it, depends on what I was doing when I stalled, and how close to critical AoA I am. I'd suggest dropping the nose, wings level, until flying again, and then adjust power and attitude to regain level flight.

As to Power and attitude. You can go back to this crash, the discussions on this forum, since about 02 June 2009, and find "fly power and attitude" as advice being the running refrain from the Greek Chorus.
Descend and get some CLs
When flying toward a line of thunderstorms? :confused: That's what AF 447 was doing.

In the military, they taught us that you go over, around, or through the bottom third of (If you had no way out and could not find a place to land) thunderstorms. Descending into one when way up in the sky ... no, they didn't teach us, and I am pretty sure they didn't teach you that.

Cheers.

forget
3rd Jun 2011, 18:50
BEagle. Do some research or at least speak to a military VC10 driver ........

Tick, tock, tick, tock ............ :E

captainsmiffy
3rd Jun 2011, 19:29
Deliberate partial panel not much fun without a turn indicator......

Lonewolf_50
3rd Jun 2011, 19:46
captainsmiffy:

Reminds me of an old Monty Python sketch

"No, not much fun in Stalingrad."

No, not much fun in the goo, in and around CBs in partial panel, or worse ... :uhoh:

Aviator62
3rd Jun 2011, 20:32
I have followed this thread from the start and some posts suggest that the problem with AF447 (and in many other incidents) may have been caused by an ice blocked pitot-tube. But my question is, Airbus must clearly have tested what a blocked pitot tube would tell the computers to do at that flight level and with that speed? Why is it that I always get the feeling that the FBW software always freaks out when the tubes are blocked and putting the crew in "what the heck is it doing now" mode. There have been so many incidents and crashes in the past by this IAS measuring device so I cannot understand why this still is a problem?

I know that IAS and GroundSpeed are totally different things as the aircraft can be flying in heavy headwind etc, but getting an indication of a sudden drop in IAS from 275 kt to 60 kt must definately be verifiable with GPS data in combination of the known headwind prior to the drop and in that way give the pilots a reading that they have NOT lost the speeds.

There must be another way to measure the aircraft's speed through the wind than just putting the trust in 3 heated tubes that seem to clog more often that wanted.

Oakape
3rd Jun 2011, 21:06
Full backstick & full power almost all the way down.

Is it possible that all the PF saw was the altimeter unwinding at a rapid rate & held full back stick & full power to recover, saying to himself that the computer won't let the aircraft stall?

Isn't that the EGPWS & windshear recovery technique as well?

xcitation
3rd Jun 2011, 22:16
The QF72 incident and the earlier QF71 could have been fresh in the minds of the AF447 crew. I recall that the QF72 ADIRU fail caused false warnings of over speed, stall, underspeed, AoA. The QF72 A330 was cruising at mid day in good weather and the erronous flight instrument readings and warnings were immediately obvious and corrected.

As noted by the BEA there were some significant differences between the computer fail of AF447 and QF72. However there was some overlap in symptoms.

The point is that ADIRU malfunction should have been a known issue to the AF crew and they presumably would have had corrective procedures. Unfortunately the ADIRU fail procedures were inappropriate/exacerbating to their true predicament of pitot icing. It would explain the counter-intuitive behaviour of the pilots apparently ignoring the flight instuments and stall warnings and pulling the nose up.

ExSp33db1rd
3rd Jun 2011, 22:33
..........No more information would reveal whatever we don't yet know, ..........

Disagree, and agree with bubbers .........

I can't believe two guys would sit there and only pass the few sparse comments that have been released, knowing what they said ( if only m***de ! ) would help understand what might have been going on on their heads and why they then took the actions that they did.

We are being treated as mushrooms at the moment, and vested interests may well prevail to sit on the full story,releasing only that which suits them - liability issues will be raising their ugly heads already, and it would be naive to think otherwise.

But then I'm a cynic.

aguadalte
3rd Jun 2011, 22:54
The FAA Stall Recovery Procedure:
http://xa.yimg.com/kq/groups/10483604/2002517561/name/Updated%20Stall%20Procedure.pdf
Addopted by Airbus Industrie
(if link doesn't work, please copy past it to your browser).

Des Dimona
3rd Jun 2011, 23:26
Read the latest Airbus Safety First magazine here for an extended discussion about the new stalling procedure:

http://www.ukfsc.co.uk/files/Safety%20Briefings%20_%20Presentations/Airbus%20Safety%20First%20Mag%20-January%202011.pdf

EGMA
3rd Jun 2011, 23:34
The FAA Stall Recovery Procedure:
http://xa.yimg.com/kq/groups/1048360...0Procedure.pdf (http://xa.yimg.com/kq/groups/10483604/2002517561/name/Updated%20Stall%20Procedure.pdf)
Addopted by Airbus IndustrieA pilot needs to be taught this ......? :ugh:

bubbers44
4th Jun 2011, 00:50
ExSp, why don't they release more information about what they know? The CVR will explain a lot of what happened. They seem to be reluctant to release a lot of results of the CVR and FDR. Eventually I guess they will have to release it. Until then all we can do is speculate about the little released. They have it all now and probably are laughing at our speculations.

barit1
4th Jun 2011, 01:55
A pilot needs to be taught this ......?

Procedure? PROCEDURE?

How about CONDITIONED REFLEX?
:rolleyes:

EXLEFTSEAT
4th Jun 2011, 01:59
Graybeard : The flight you are referring to was operated as TW841. It was not NWA.

dcasali
4th Jun 2011, 03:45
SMOC

The forum post was on 1 June. The article referenced in it is dated 1/06/11.
Here is the link from #1242:

#1242 (http://www.pprune.org/6487013-post1242.html) (permalink (http://www.pprune.org/rumours-news/447730-af447-wreckage-found-63.html#post6487013)) JamesT73J (http://www.pprune.org/members/77036-jamest73j)

Join Date: Oct 2003
Location: Hampshire, UK
Posts: 159


According to flight global, automatic stab trim should have been inhibited when alpha > 30 degrees - Stalled AF447 did not switch to abnormal attitude law (http://www.flightglobal.com/articles/2011/06/01/357394/stalled-af447-did-not-switch-to-abnormal-attitude-law.html) but it was not.


Finally, here is the initial text copied from the FlightGlobal article:

DATE:01/06/11
SOURCE:Air Transport Intelligence news

Stalled AF447 did not switch to abnormal attitude law
By David Kaminski-Morrow ([email protected])
http://aka-cdn-ns.adtech.de/apps/404/Ad6389652St3Sz277Sq100553095V2Id5/158271971
http://adserver.adtech.de/adserv%7C3.0%7C289%7C1061237%7C0%7C277%7CADTECH;loc=300;key= key1+key2+key3+key4;grp=[group] (http://adserver.adtech.de/adlink%7C3.0%7C289%7C1061237%7C0%7C277%7CADTECH;loc=300;key= key1+key2+key3+key4;grp=[group])

Investigation into the accident sequence of Air France (http://www.flightglobal.com/landingpage/air%20france.html) flight AF447 has revealed that the Airbus A330 (http://www.flightglobal.com/landingpage/airbus%20a330.html) did not enter the abnormal attitude law after it stalled, despite it

Graybeard
4th Jun 2011, 04:09
Thanks ExLeftSeat. As a politician would say, "I misremembered; I misspoke; it happened Northwest of New York" etc. I'll go back and fix it.

ExSp33db1rd
4th Jun 2011, 04:10
bubbers44...... why don't they release more information about what they know?

I don't know, I'm sure that there will be a protocol about the procedure that they are correctly using at the moment, and this isn't a final report anyway. If they withhold the full scope of the CVR finally, then I think that a lot of people with a right to know will be asking why.

Bet your bottom dollar lawyers and insurance assessors are keeping a close eye on it all and doubtless advising what should and what should not be released until they are ready for the full story - and with it the apportionment of blame - to be released.

but then ... just as some burglars fall over and beat themselves up whilst resisting arrest, who knows exactly how much of the CVR was preserved whilst at the bottom of the Atlantic, and available when the boxes were opened ?

but then I'm a cynic.

Mimpe
4th Jun 2011, 04:59
Do you guys get to hand fly IMC at cruise flight levels or is it just too stall-prone? Just a curious question.

Ikeep wondering what I would have done.

stall alarms leads to (immediate....thought never ever ever ignore this..)

-same power ( ie minimum change in known cruise settings as your speed indicator has just dropped out)
-a little immediate gentle nose down alteration in elevator pitch ( you would have memorised the pitch attitude and AoA in cruise before bed every night in preparation for this precise moment...)..anything to make the stall warning go quiet and get some airover the wings
-wings level
- and an immediate check of the autotrim setting (as it seems thats the Airbus elephant in the room if theres no elevator authority and you're nose high +++ and descending at 10,000 fpm!) sound like good initial steps to me, and ..
-fly it first and foremost on meticulous instrument scan, and worry about all the alarms and noise later ( stall warning excepted of course)
-gradual turn away from track and storm if one has to
-dont worry about altitude loss as its the best friend you have - in fact lose 10 000 feet very gradually and you'll feel even better about the stall risk im sure

I only fly a Duchess.

wiggy
4th Jun 2011, 05:30
Do you guys get to hand fly IMC at cruise flight levels

No, and especially not since the introduction of Reduced Vertical Separation Minima (RVSM) airspace over a lot of the world.

Oakape
4th Jun 2011, 05:36
or is it just too stall-prone?

Not normally, no.

Mimpe
4th Jun 2011, 05:44
Thank you for the Information - then it must have made the sudden alteration in the situation seem all the more challenging for the poor pilots - having to hand fly in circumstances not previously familiarised , with no speed indication , in IMC/Storm conditions.

TwoOneFour
4th Jun 2011, 11:06
According to flight global, automatic stab trim should have been inhibited when alpha > 30 degrees


The article doesn't say that - what it says is that Alpha > 30deg is one threshold for switching to abnormal law, but that other conditions were not met, because the Flt Ctrl computer rejected the air data.

TTex600
4th Jun 2011, 18:02
Tip of the iceberg...?
From pointers to drums... From dynamics to numbers...

Tiny observations large outcome...

When I started flying ‘digital’ I missed and preferred the ‘old’ familiar dynamic moving pointers on the Airspeed indicators and Altimeters, rather than the relatively ‘dumb’ moving number-tapes and/or drums on the flight displays.

And my ‘emotion’ is not limited to Airspeed indicators and Altimeters only.

Of course, as with all sort of changes, I was told that I “just have to get used to it!”

OK... Fair enough... But, although I am getting more and more used to ‘flying digital’ by now, on occasion, I really sense the lack of instant dynamic ‘speed and altitude situational awareness’ that the ‘old’ analogue Airspeed indicators and Altimeters with their moving pointers will give us more or less instantly.

Looking at the tapes I have to figure out: Are the changes going up or down? Moving Fast or slow? Is it an increase or a decrease? What’s the trend? Things, that I would instantly be aware of with the analogue indicators. With digital indicators, however, I need more of my brain capacity to ‘translate’ the sheer changing of numbers on the rolling tapes (or drums) into dynamics.

Oh, yes... We’ve got the ‘speed trend arrow’ to sort the speed thing out... Haven’t we... But, then again, isn’t this turning the things upside down?

In every new aeroplane that our company receives, even the ‘last resort’ analogue standby instruments have been replaced by a single digital display.

Man tries a lot of things to improve safety. On the other hand, in my opinion, these efforts are broken down again, unnoticed.


As for hindsight typing behind the computer:

Most of our daily flying ends at a couple of hundred feet going out and starts again at a couple of hundred feet coming in... Almost every flight we are being flown, mostly by the comfort of automation, very near to the ‘coffin corner’... The ‘gap’ being smaller one time than the other. I wonder how many of us really actively realise this...

At high altitude in the very thin air, especially in turbulence at night, a cockpit can turn into a relative ‘hell’ very abruptly if the Autopilot kicks off... (LOL most probably from many in here...) Controls will be very sloppy in conventional aircraft. In FBW aircraft this will be even more (un) noticeable, as there is different or no direct feedback.
In both cases, while you’re shaking, you need to handle the controls like being a Swiss watch maker. And you are now manually manoeuvring within this tiny confined little gap... If you’re lucky you may have done it may be a couple of times. Even ‘minutes’ would do a great deal of benefit already... But it is something we hardly actually ever do...!

Are we stupid, then? We train constantly for all sorts of situations... Or could here be a training deficiency? If you have/were never trained in hand flying close to the ‘edges’ of an envelope (or even outside an envelope), or if you have never actually been hand flying close to the ‘outside’ of an envelope, chances are that you won’t even notice that you’re going out... Whilst thinking you’re ‘hanging in there’... And so far, so good...

How much ‘flight time’ were our unfortunate colleagues granted to log in their logbooks on actual hand flying the plane in that tiny little gap, before they all of a sudden were forced and committed to do so in a very, very narrow gap. Whilst probably shaking, vibrating and being bombarded with all sorts of alarms going off...

So, whilst trying to analyse, I have learnt to always remain respectful and very humble and do a great deal of effort to see the whole picture...
29th May 2011 at 21:03.I normally just lurk here occasionally. I've wanted to join this string but up til now I've refrained because of the shear volume of posts. But Learner001's post bears kudos.

Well said Sir, well said!

tigger1965
4th Jun 2011, 19:36
i'm not a pilot, know nothing about flying.

i'm curious to know if a large commercial airline has ever been successfully recovered from a deep stall such as occured in this case ?

either in test flights, real life or even on a sim ? is it actually possible and if so what altitude would be required?

i assume would require a change from tail down via wing down to nose down attitude, and that would be very tricky and unstable, risking spinning or going upside down and using up lots of altitude ?!

lomapaseo
4th Jun 2011, 20:46
i'm curious to know if a large commercial airline has ever been successfully recovered from a deep stall such as occured in this case ?



whether the number is 1 out of 100, 1 out of 10 or zero out of 5 makes little difference.

The answer comes out that the denominator needs to approach zero.

kilomikedelta
4th Jun 2011, 22:01
That would give you a number approaching infinity. Computers do very strange things with denominators that approach zero - like crash.

bearfoil
4th Jun 2011, 23:32
Okay, how about the result is unity. 1/1. Every Stall gets a recovery.

Picky kmd. ;)

kilomikedelta
4th Jun 2011, 23:46
Bearfoil; AF447 didn't recover. My point was that floating point operations in computers with a finite operand length when encountering a divide by zero may do peculiar things and that the interrupt to handle that exception has to be VERY well defined. Cheers.

HarryMann
5th Jun 2011, 00:03
I assume would require a change from tail down via wing down to nose down attitude, and that would be very tricky and unstable, risking spinning or going upside down and using up lots of altitude ?!

Why on earth do you say that ? :rolleyes:

Best read the few thousand previous posts on all AF447 threads to catch up a bit first, then maybe post.

Mimpe
5th Jun 2011, 00:51
I'm studying post graduate aviation medicine at present

There is a physiologic reason why pilots prefer analogue to digital readouts, and why smaller moving number images attract less attention than dials moving.

The occipital cortex ( via magnocentral pathways via lateral geniculate nuclei)is hard wired to interpret visually perceived movement as potential danger without reference to "higher centres" interpeteting the visual data.

ie if you saw an analogue altimeter unwinding the brain links to potential danger are more immediate, and the same would apply to the VSI in typical analogue form.

When its moving tapes of numbers occuppying less visiual space and requiring more intellectual input to interpret , its natural to feel less concerned, and in fact the brain is hard wired to feel less concerned.

All of this adds to increased risk at the edge of the flight envelope...

kilomikedelta
5th Jun 2011, 01:29
You are right. The occipital cortex is more sensitive to peripheral field movement (millenia of evolution) compared to changes within the macular areas of the cortex. Engineers and flight deck crew are not taught that which may be why they gravitate toward digital displays until their occipital cortex clashes with their cerebellum. Whence spatial disorientation.

Machinbird
5th Jun 2011, 01:46
Mimpe gets an attaboy:ok:
I'm studying post graduate aviation medicine at present

There is a physiologic reason why pilots prefer analogue to digital readouts, and why smaller moving number images attract less attention than dials moving.

The occipital cortex ( via magnocentral pathways via lateral geniculate nuclei)is hard wired to interpret visually perceived movement as potential danger without reference to "higher centres" interpeteting the visual data.

ie if you saw an analogue altimeter unwinding the brain links to potential danger are more immediate, and the same would apply to the VSI in typical analogue form.

When its moving tapes of numbers occuppying less visiual space and requiring more intellectual input to interpret , its natural to feel less concerned, and in fact the brain is hard wired to feel less concerned.

All of this adds to increased risk at the edge of the flight envelope...

A very good reason why old fashioned instruments are useful as standby instruments. Lets hope all the old fashioned instrument makers and repair guys haven't already retired.

I may be one of those 'dinosaur pilots', but by gosh, I know truth when I see it.

Even a moving needle on a digital display doesn't get the mental recognition and attention that the real thing gets.

kilomikedelta
5th Jun 2011, 02:00
The old gravity dependent turn and bank indicator and the magnetic compass rely on forces that are difficult to manipulate by publicists or lawyers. They give you pitch, attitude and yaw but not in 3D with Hollywood star endorsements and stock options so why would anyone even look at them?

bearfoil
5th Jun 2011, 02:09
A flight deck is no place to rely on the amygdala, least ways not in cruise.

It is said that it is a good bet that those of us alive today had ancestors who were good at spotting movement, not detail. Detail is for which part of the animal we wish to consume. Noticing movement keeps us out of the sabre tooth's maw.

Left Brain digital; good for ennui producing comfort, the time after the hunt, and for making spears. The ever ready amygdala wears us out, and makes us quick prey for the threat we don't see, being exhausted from hyper vigilance.

The computer has no skin in the game, save for the Hubris of those who built it, sold it, and equip there a/c with it.

Complex is for rules. Simple is for survival. We have known that for thousands of generations, yet we convince ourselves it is 'different' now, we have 'evolved'.

Of the hundreds of times I have stalled a flying a/c, not one time was it inadvertent. Once on approach, a traffic conflict got too much of my attention, and I got slow. I started a turn, and heard the horn. I am happy to say I did not have to think, consult a manual, or radio for assistance.

Nothing like the hangman's noose to focus one's attention.

This path started by Mimpe is very germane. Google University of California, The Mind Institute. Wander into the Hall of "Brain Mapping".


Just to put a little anxiety into our fbw partisans. I will wager that prior to ai flying a plane, the brain will be connected through electrodes to a/c controls, and said brain will fly that a/c in ways that rules based ai could never accomplish. Case a Guinness.

engine-eer
5th Jun 2011, 02:22
Even a moving needle on a digital display doesn't get the mental recognition and attention that the real thing gets.

Remember in the mid-eighties that a lot of performance cars were going to video display full digital dashboards with no analog gages????

Then the guys actually running cars on the track figured out that good old analog gages were actually better. They found the driver didn't have to actually look at the gages to know all was ok and what the car was doing. The information was received and processed by the subconscious within the normal scan of the instruments because the regular positions of the needles were within the driver’s memory. Not sure that tapes can give the same situational awareness as good old fashioned gages.

I'm sure modern glass cockpits are much better than steam gages, but maybe there are some things like altitude, airspeed and vertical speed that might be better presented by a gage.

mm43
5th Jun 2011, 02:26
Originally posted by bearfoil ...

Complex is for rules. Simple is for survival. We have known that for thousands of generations, yet we convince ourselves it is 'different' now, we have 'evolved'.A little stocktaking is now required ... well said bear.:ok:

BreezyDC
5th Jun 2011, 03:02
Speaking of brains and our human response to various stimuli -- computer aided or not -- what would the "seat of the pants" part of the pilots' brains be experiencing?

In this type of stall, would they feel increased positive G's which would then seem to decrease (or even go negative) as they rapidly descend in the continued stall? I gather the BEA will provide a graph with G forces plotted with a full report of FDR data, but no doubt it could influence the pilot's actions or lack thereof.

BobT
5th Jun 2011, 03:37
KMD: That is one of the reasons floating point operations are avoided in control systems. Other representations/encodings are invented.

Machinbird
5th Jun 2011, 04:39
BreezyDC
Speaking of brains and our human response to various stimuli -- computer aided or not -- what would the "seat of the pants" part of the pilots' brains be experiencing?

In this type of stall, would they feel increased positive G's which would then seem to decrease (or even go negative) as they rapidly descend in the continued stall? I gather the BEA will provide a graph with G forces plotted with a full report of FDR data, but no doubt it could influence the pilot's actions or lack thereof.

The following applies to the developed steady state stall:
If they were not accelerating or decelerating and the wings were level, and the nose was 16 degrees in the air, then they would feel like they were in a slight climb attitude, but without that push in the back that says you are accelerating.

When a wing drops in the stall, the wing is still generating some lift which can turn the aircraft, but since the aircraft fuselage is also now being supported somewhat by the uprushing air, there will be much more lateral acceleration (downward) than you customarily experience in a wing down attitude.

When in doubt remember, all forces have to be in balance or the aircraft would be accelerating.

Mimpe
5th Jun 2011, 04:56
As all you would know, their seat of the pants would be

a) screaming at them when they shouldn't or
b) not screaming at them when they should
c) or ( most probably ) both at once


and most of the resulting spatial inferences in this situation would be incorrect and dangerous

Machinbird
5th Jun 2011, 04:56
engine-eer
I'm sure modern glass cockpits are much better than steam gages, but maybe there are some things like altitude, airspeed and vertical speed that might be better presented by a gage.
I would like to point out, that "better" has different modes of comparison.
Price? Cost of ownership? Reliability? Ease of maintenance? Intelligibility?
More easily integrated into the instrument panel? More rapidly assimilated?
ETC.

It is all a tradeoff. The issue is how to cover the maximum number of bases, and still give the crew what they need in the worst case they may face.

A mix of old style (steam gage) and new instruments (digital) can best do this.

Motorola
5th Jun 2011, 06:27
Another hi alt stall Report: West Caribbean MD82 at Machiquez on Aug 16th 2005, did not recover from high altitude stall (http://avherald.com/h?article=4308e7d6&opt=0)

HazelNuts39
5th Jun 2011, 08:17
In this type of stall, would they feel increased positive G's which would then seem to decrease (or even go negative) as they rapidly descend in the continued stall?
Here is a graph (https://docs.google.com/leaf?id=0B0CqniOzW0rjYjY2ZGRhNzUtYjIzYy00ZTM5LTkxNjYtMzZlMGY yYzY5Zjkw&hl=en_GB&authkey=CLeNnpMK) showing my estimate of the G's that produce the trajectory and speeds described in BEA's Update.

tigger1965
5th Jun 2011, 09:26
to Harryman

'Best read the few thousand previous posts on all AF447 threads to catch up a bit first, then maybe post.'

Thankyou for your slightly patronising tone! I have already read all posts. If you think I have said something dumb, please could you explain - I would prefer to be educated than mocked ! thanks, paul

Mr Optimistic
5th Jun 2011, 10:09
HN39, am I reading your graph correctly ? Shortly after 2:10:30 the a/c started to descend (g less than 1.0) at which time the pitch was greater than 10 degrees (and increasing) and the FPA was about 8 degrees and just about to max ?

Presume in a stall vertical acceleartion (g) is less than 1 and FPA will decrease, so are there two stalls, each starting where FPA starts to decrease (and g about 1 and falling ?).

HazelNuts39
5th Jun 2011, 10:39
HN39, am I reading your graph correctly ? No, you are not reading the graph correctly. Perhaps you should read it together with another graph (https://docs.google.com/leaf?id=0B0CqniOzW0rjZWNjMzNmZDAtNTk3Yi00NWQzLTlkYjctZGQ0Yjk 2Nzk4ZjE5&hl=en_GB&authkey=CMjmmEw) that shows vertical speed and altitude.

Per BEA the airplane stalls around 2:11:00, after AoA exceeds alphamax and then approx. 9 degrees and continues increasing as shown in the first graph. At 2:10:30 the vertical acceleration reduces to less than 1g. Vertical acceleration above/below 1g is the rate of change of vertical speed, which is 7000 fpm at that point and starts reducing to 700 fpm.

ExSp33db1rd
5th Jun 2011, 11:21
...........pilots prefer analogue to digital readouts,...........

Agree.

I long ago threw away one of those new-fangled Seiko World Time digital watches, one looks at The Picture on a normal watch, don't have to 'read' and assimilate the information.

Mind you, I then went for one of those Glycine jobs where the hour hand goes around only once in 24 hours, so that 12 Noon is at the bottom - that threw me for awhile !

doubleu-anker
5th Jun 2011, 11:34
There is one way to settle this once and for all.

Get Airbus test crews to take up an A330, with the same w & b and put the thing into a deep stall. Ballast could be gleaned from the sales team. The data from the result could be feed into all the A330 Sims and it could benefit all.

They wouldn't need parachutes as the AB is uncrashable I am told as the built in protections and proper pilot's would guard against this..

Mr Optimistic
5th Jun 2011, 11:45
HN39, OK, thanks. Will have a bigger think.

Machinbird
5th Jun 2011, 13:59
doubleu-anker
There is one way to settle this once and for all.

Get Airbus test crews to take up an A330, with the same w & b and put the thing into a deep stall. Ballast could be gleaned from the sales team. The data from the result could be feed into all the A330 Sims and it could benefit all.

They wouldn't need parachutes as the AB is uncrashable I am told as the built in protections and proper pilot's would guard against this..

Doubleu-anker, I know your are being a bit facetious, but the core of the idea has merit.
Suppose we took a life-limit A330 or a ferryable but badly damaged aircraft, mounted high time engines, installed an ejection seat for the test pilot (singular), installed a ballast control system so you could move the c.g. around quickly, installed high speed telemetry, and went flying.
You could fill all the high risk niches of the A330 performance curves with relatively low human and financial risk. Might even collect enough data in one flight to do the job.
And when you get done you will have one sweaty test pilot who is an expert in flying the A330 at any angle of attack.:}

hetfield
5th Jun 2011, 14:11
...as the AB is uncrashable I am told...Yes, that's what these arrogant frogs were trying to make people and airline managers believe.

This arrogance was payed with blood pretty soon and some airlines made up their mind to improve training and not to reduce it, like the smart AB managers suggested.

Machinbird
5th Jun 2011, 14:18
HN39, I looked at the second graph, and see that toward the right side, there are vertical velocities up to 13,000 fpm. I gather that you have integrated the whole postulated flight path so that the end time works out the same as the real deal.

I also interpret all the acceleration figures to be relative to the surface of the earth. Have you worked out the perceived accelerations relative to the aircraft axis? That would give us the seat of the pants feel, or have you already made this transformation?

Machinbird
5th Jun 2011, 15:13
MOTOROLA
Another hi alt stall Report: West Caribbean MD82 at Machiquez on Aug 16th 2005, did not recover from high altitude stall (http://avherald.com/h?article=4308e7d6&opt=0)

Thanks for that report. I hadn't seen it before and it is relevant. The crew in the linked report tried to get more performance from the aircraft than they should, but autotrim is what led them down the primrose path.

I wonder if we still had the trim buttons on the stick/wheel whether we would be having this type of accident?

Yes, trim runaways seem to be prevented with properly designed autotrim, but the surreptitious changing of trim without annunciation is clearly hazardous.
At the minimum, the Airbus needs some sort of loud clicker when it changes trim so that the crew is aware of what it is doing.

A whole string of loud clicks would be a warning to see what is going on.
But with the AF447 commotion in the cockpit, would it have been audible?
Over to you, Airbus, for some redesign work.

ChristiaanJ
5th Jun 2011, 15:48
A whole string of loud clicks would be a warning to see what is going on.
But with the AF447 commotion in the cockpit, would it have been audible?
I thought "traditionally" the pitch trim wheel went "ping, ping, ping" like a bicycle bell?
Easily distinguished from just about everything else.

HazelNuts39
5th Jun 2011, 16:13
Machinbird;

First three sentences: Yes. On the other hand, I was mainly interested in the motion of the airplane, and did not work out the "seat of the pants feel". The lift coefficient and hence alpha is based on the acceleration normal to the flight path.My data do not go beyond alphamax, so anything beyond that should be taken with the appropriate grains of salt.

Zorin_75
5th Jun 2011, 16:52
Another hi alt stall Report: West Caribbean MD82 at Machiquez on Aug 16th 2005, did not recover from high altitude stall (http://avherald.com/h?article=4308e7d6&opt=0)
That's a depressing read. At least they got around to radio ATC for clearance to fall out of the sky :ooh:
(http://avherald.com/h?article=4308e7d6&opt=0)

rak64
5th Jun 2011, 18:08
- the absence of appropriate actions to correct the stall of the aircraft (from Report: West Caribbean MD82 at Machiquez on)

Hi

to fill some emptiness (no job presently) I started to build a model into x-plane, a simuator game that claim to calculate air forces mostly correct.
I did a blended wing, during flight tests i got severe problems to recover high altitude stalls. I figured out a reliable procedure for x-plane to recover from such a stall.

First let my say all what is reported here about that behavior looks reasonable to me. The 7000ft/min compares perfect to the trim setting. (What is not fully correct the trimsetting is corret for the speed 60-80 IAS, but the vvi is looking good for the flight maneuver.)
The stall speed is independent from altitude regarding IAS as long no oblique shock or vortex occurs.

My problem was after the stall the ACFT reached a stable position with 20-30 degrees AoA what i not could not terminate. After many crashes I decided to fly the stall what mean not try to recover early by pressing the yoke forward. I pulled gently until the rear stop was reached, power idle, engine secured by igniter, while gamble to keep wings leveled, checked the horizontal trim settings (I found best was take off trimm working). When reached that carefully move the yoke forward to reach more than 30 degrees downwards but not more than 60 degrees. While dive let the speed increase, just a little below maneuver speed bring pitch to the horizon. Reset power.

This is not the procedure for reacting for a stall warning alarm, what still is just add power. It is for my little blended wing in x-plane. I never lost more than 10000 feet but thats better than an impact.

engine-eer
5th Jun 2011, 18:19
Speaking of brains and our human response to various stimuli -- computer aided or not -- what would the "seat of the pants" part of the pilots' brains be experiencing?

In this type of stall, would they feel increased positive G's which would then seem to decrease (or even go negative) as they rapidly descend in the continued stall? I gather the BEA will provide a graph with G forces plotted with a full report of FDR data, but no doubt it could influence the pilot's actions or lack thereof.

If they stalled it at a load factor of less than one g, that would result in a stall at a considerably lower speed. The Airbus Safety newsletter mentioned that buffetting would occurr as the aircraft approached stall.

But in this case, if the aircraft stalled at less than a G, the speed would be lower and there may not have been any or much buffetting. If that is the case, the PF may not have felt enough of a stall or break to make him think he had actually stalled it. Stall horns go off when you approach stall, not after you stall.

What very well could have happened is that as the stall warning started and the PF applied TOGA. The aircraft didn't buffet, shake or break into a conventional stall, it stopped flying and started falling at a lower speed.

Absent the break or buffett, when the stall horn stopped the PF likely thought that he flew out of the approach to stall and was flying again. All speculation, of course, but if that is what happened it would offer an explanation of what the PF thought and would explain a lot better his actions.

SDFlyer
5th Jun 2011, 20:27
Engine-eer,
Sounds like a very plausible scenario to me, i.e. non-recognition of the full stall at the start (after intial nose-down following recognized impending stall) for reasons stated. But what is so baffling is that the PF (and others) would persist in such a belief in the face of a rapid and continuing descent for 30K ft with the stick full aft and substantial nose-up attitude (even if credibility in IAS never returned). [Assumes all relevant data provided by BEA, skeptical icon ...]. Of course a continuing stall alarm would have helped greatly one assumes but really, at some point reality should have dawned, leading to forward stick +/- power, i.e. at least an attempt at recovery.

Sorry to bring the discussion back to this issue but for me it's the most troubling one in a way. Let's hope the CVR will reveal much more about state-of-mind of some or all involved.

<returns to piston gallery>

Machinbird
5th Jun 2011, 22:01
I thought "traditionally" the pitch trim wheel went "ping, ping, ping" like a bicycle bell?
Easily distinguished from just about everything else.
Christian, for things Boeing, I believe you are correct.

A while ago on earlier threads, PJ2 briefed that the A330/340 trim wheel moved silently.

Don't know why they made that decision at Airbus, but I think they need to revisit it.

ChristiaanJ
5th Jun 2011, 22:10
Christian, for things Boeing, I believe you are correct {re "ping ping"}.
As far as I remember, same thing on Concorde (Sud-BAC, then Airbus).
I'll have to check, or ask friends to check.
If even to an ancient as myself that was "obvious", one does wonder why it was changed.

tubby linton
5th Jun 2011, 23:56
The A300-600 has a whooler if there is more than a few seconds trim operation but it is cancelled when the autopilot is engaged.

jcjeant
6th Jun 2011, 01:58
Hi,

I think pprune can thank the BEA to have generate as much traffic on their forums by making public only a few fragments of the CVR
It is as if BEA would cause an outbreak of rumors ... not the best effect on the public.
When we know that their goal was to silence the rumors appeared in several newspapers .. it seems quite successful. :8
In short .. BEA com in all its splendor
One may wonder how to make public the entire CVR (less passages not related to technic matters) would prevent the ongoing and the result of the investigation to proceed calmly and with the confidence of the public.

lomapaseo
6th Jun 2011, 02:52
One may wonder how to make public the entire CVR (less passages not related to technic matters) would prevent the ongoing and the result of the investigation to proceed calmly and with the confidence of the public.

The public calms down and moves onto the next disaster du jour when a a paper or talking head explains a theory to them with authority (one voice).

Since PPRune never speaks with one voice the media only use PPRune to incite questions.

So let's just carry on with our multiple theories based on what scraps of fact are fed to us :}

xcitation
6th Jun 2011, 03:59
jcjeant


Hi,
I think PPRuNe can thank the BEA to have generate as much traffic on their forums by making public only a few fragments of the CVR
It is as if BEA would cause an outbreak of rumors ... not the best effect on the public.
When we know that their goal was to silence the rumors appeared in several newspapers .. it seems quite successful.
In short .. BEA com in all its splendor
One may wonder how to make public the entire CVR (less passages not related to technic matters) would prevent the ongoing and the result of the investigation to proceed calmly and with the confidence of the public.

Red section...what are you suggesting?
The transcript of the CVR needs to be complete. Otherwise how do we know AF447 maintained a sterile flight deck? The Buffalo incident is a good example of non-sterile environment to the point of distraction in my humble opinion. Lest those lessons never be learnt.
Transparency is the only way forwards. Otherwise who do you suggest should erase parts of the transcript, AF, BEA, French Judiciary...?

doubleu-anker
6th Jun 2011, 04:12
"Transparency is the only way forwards."

I agree. Nothing good will ever come from secrecy, whether it be from a group, organisation, authority or society.

A certain European country learnt it's lesson last century. Their equivalent of parliament now has a glass dome for a roof.

RWA
6th Jun 2011, 04:45
Trouble is, any advertising/PR guy will tell you that first impressions last a long time - and, in many peoples' minds, for ever......

Some quite respectable newspapers, for example, appear to have got the impression that the pilot caused the initial 'steep climb.' Even the BEA thing doesn't actually say that - indeed, in very 'spare' wording, it rather confirms the opposite, that the pilot countered the climb with 'nosedown control inputs' and restored the aeroplane to a situation of reasonable airspeed and a reasonable AoA:-


"The airplane’s pitch attitude increased progressively beyond 10 degrees and the plane started to climb. The PF made nose-down control inputs and alternately left and right roll inputs. The vertical speed, which had reached 7,000 ft/min, dropped to 700 ft/min and the roll varied between 12 degrees right and 10 degrees left. The speed displayed on the left side increased sharply to 215 kt (Mach 0.68). The airplane was then at an altitude of about 37,500 ft and the recorded angle of attack was around 4 degrees."
So we're really no further forward as to what caused the stall in the first place?

But BAE's repeated mentions of 'noseup inputs' later on appear to have put over an impression that the pilot caused the whole thing?

My own position is that the BAE would have been 'within its rights' not to publish the CVR this early in the investigation. Alternatively it could have published the whole of it. But just publishing a few isolated quotes is, in my view, plain wrong.

And its also clear that, from the rest of the text, with its descriptions of control movements, power settings etc., they've already analysed quite a lot of the FDR information too. Again, I'd have preferred 'all or nothing.'

Zorin_75
6th Jun 2011, 06:50
Some quite respectable newspapers, for example, appear to have got the impression that the pilot caused the initial 'steep climb.' Even the BEA thing doesn't actually say that - indeed, in very 'spare' wording, it rather confirms the opposite, that the pilot countered the climb with 'nosedown control inputs' and restored the aeroplane to a situation of reasonable airspeed and a reasonable AoA:-

If you look at the paragraph preceding your selective quote (timestamp 11s earlier), you will find:
The airplane began to roll to the right and the PF made a left nose-up input. The stall warning sounded twice in a row. The recorded parameters show a sharp fall from about 275 kt to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments later in the speed displayed on the integrated standby instrument system (ISIS).

I concur that we don't know enough about the nature of that input to conclude with certaincy it caused the climb, but there's nothing in that note saying it didn't. So far the chain of events NU input by PF -> climb -> ND input -> reduced climb is the least complicated (and thus probably a likely) way to connect the few dots we have.

Jazz Hands
6th Jun 2011, 07:28
Some quite respectable newspapers, for example, appear to have got the impression that the pilot caused the initial 'steep climb.' Even the BEA thing doesn't actually say that - indeed, in very 'spare' wording, it rather confirms the opposite, that the pilot countered the climb with 'nosedown control inputs' and restored the aeroplane to a situation of reasonable airspeed and a reasonable AoA


Sounds to me that you're making exactly the same assumption in reverse.

M.Mouse
6th Jun 2011, 08:02
....would prevent the ongoing and the result of the investigation to proceed calmly and with the confidence of the public.

The investigation is without a doubt proceeding calmly. I am sure 99.99% of the public don't care/are not interested/have confidence. This thread is mostly pointless speculation with most of it being complete nonsense written by people who no little about flying jet transport aircraft e.g.The transcript of the CVR needs to be complete. Otherwise how do we know AF447 maintained a sterile flight deck?

Sterile flight deck? What?

I read this thread for amusement and for the occasional gem like post #1208.

aterpster
6th Jun 2011, 10:07
Zorin 75:

That's a depressing read. At least they got around to radio ATC for clearance to fall out of the sky

What's depressing is how easy the recovery could have been by trading altitude for speed. That requires putting to nose well down in such circumstances followed by a judicious application of power.

Lonewolf_50
6th Jun 2011, 12:34
aterpster: what I found most striking in the MD82 event was that the nose trim kept going up ... similar to what AF447 has.

Nose drop to lower AoA. Speed up. Watch RoD decrease.

I've been watching the comments on round versus strip gauges and personally agree: the strips don't give me the same "feel" as round gauges. Thanks to mimpe for a bit of an explanation on that. :ok:

Jetstream67
6th Jun 2011, 14:13
Quote:
That's a depressing read. At least they got around to radio ATC for clearance to fall out of the sky

The lack of a distress call (or actually any call) from AF447 has never been resolved. Wonder if this was a conscious decision ?

forget
6th Jun 2011, 15:03
There was some discussion on the 'Trim Running' aural alert, but no conclusion. Some thought it was 'ding ding' bell. (Never heard of that for trim.) Others a traditional 'trim clacker' - which you'd sort of expect. Someone suggested a clacker that only sounded after several seconds of trim running. Whatever it is, it should be on the CVR - but what is it?

JamesT73J
6th Jun 2011, 15:10
With reference to old-style instruments, flat-panel displays are getting bigger and bigger. No reason the same style cannot be used digitally to mimic the sacred six.

Carjockey
6th Jun 2011, 15:29
Going to draw some flak here I know, but I have a couple of questions for you guys.

FYI, I am a just a lesser human being (a concerned SLF) but I believe I have a right to expect that aircraft manufacturers and airline operators ensure that I can travel from A to B safely and with confidence.

So here we go:

1.If the AP/AT systems on an A330 are designed to disengage when they encounter a situation which they cannot handle, and immediately hand over control to the pilots in the 'driving' seats, why are the pilots not provided with a clear reason, or at least a good indication, as to why the AP/AT disengaged in the first place?

2.Are the automated systems on this aircraft, or on any other commercial passenger aircraft, capable of detecting a potentially dangerous TS storm system, and of warning the pilots of their aircraft's proximity to the same?
If not, why not?

3.Has the logic of initiating automated multiple audio/visual alarms simultaneously in the cockpit of an aircraft in flight and in a critical situation, and the phsycological effect of this on the pilots in that situation, ever been thoroughly studied and investigated?
If not, why not?

Despite the recovery of the CVR/FDR, the fact is that nobody will ever really know the cause of this accident. CVR/FDR will provide clues but, as with so many serious aircraft accidents, nobody will ever know for sure what really happened here.

But I would suggest that the interface between aircraft automation and consequent human reaction to that automation, played a large part in this particular tragedy.

'Nuff said...

Machinbird
6th Jun 2011, 15:33
With reference to old-style instruments, flat-panel displays are getting bigger and bigger. No reason the same style cannot be used digitally to mimic the sacred six. I believe we just pointed out that a digital display does not have the same attention getting power of the actual instrument.

With regard to the standby instruments, why would we want to do that?:ugh:
Diversity of instrument types can have benefits.
We have already put the 'sacred six' on the PFD, haven't we?

Machinbird
6th Jun 2011, 15:37
Despite the recovery of the CVR/FDR, the fact is that nobody will ever really know the cause of this accident. CVR/FDR will provide clues but, as with so many serious aircraft accidents, nobody will ever know for sure what really happened here. I will bet they will know for sure to the level that you can bet your life on the result.
If you want absolute certainty, then you are living in the wrong world.:rolleyes:

ATC Watcher
6th Jun 2011, 15:59
The full CVR will be made avail to the general public sooner or later unfortunately( or fortunately depending on which side you're on ). In the days of I-phones which can record anonymously anything 10m around you and given the media attention this perticular accidents has, it is only a matter of time I would say.
In anycase, since there will be a trial, the defence lawyers in France will have access to it and will reveal it, as they did in the Quiberon, Brest and Pau accidents, and then it will be including all the" sterile cockpit" discussions. Trial of the crew by Media. The New Zealand and Canadian approach is far superior.

Ask21
6th Jun 2011, 16:00
My problem was after the stall the ACFT reached a stable position with 20-30 degrees AoA what i not could not terminate. After many crashes I decided to fly the stall what mean not try to recover early by pressing the yoke forward. I pulled gently until the rear stop was reached, power idle, engine secured by igniter, while gamble to keep wings leveled, checked the horizontal trim settings (I found best was take off trimm working). When reached that carefully move the yoke forward to reach more than 30 degrees downwards but not more than 60 degrees. While dive let the speed increase, just a little below maneuver speed bring pitch to the horizon. Reset power.

I'm not sure if I got it right - What was the THS-trim at stable stalled configuration - Was auto trim working?\ - how slow was trim reduced - what was elevator position during trim-reducing. What was trim when recovered?
What about Center of gravity - and the posterior trim tank?

Those procedures should be tried in an full-scale simulator (actually I'm kind of shocked that there seems to be no developed procedure to recover from fully developed semi-flat stalls - and even little practice in simulator) - -

ap08
6th Jun 2011, 16:01
I will bet they will know for sure to the level that you can bet your life on the result.
If you want absolute certainty, then you are living in the wrong world.
6th Jun 2011 15:33
in accidents like these, there is a lot of contributing factors, neither of which could have caused the crash by itself. However, when they are working together, there is a synergy between them which leads to disaster. Even if you had all the data, you might not be able to tell if the crash really happened because of flying into thunderstorms, or pitot tube design, or lacking AoA indication, or excessive unmanageable automation, or lack of high speed, high altitude stall training/awareness, or something else. You can pick one reason and call it THE reason, but others will disagree with you, and the argument will just go on endlessly.

JamesT73J
6th Jun 2011, 16:03
I believe we just pointed out that a digital display does not have the same attention getting power of the actual instrument.

No, I think the point was the format of the instruments as seen on a PFD is not as conducive to subconscious comprehension. Drum vs radial scale, etc. Whether this is steam-driven, crt or LCD doesn't really matter.

Some of the bizjet & GA panels are doing a pretty impressive job with this these days. I'm sure it's an area that will continue to be refined.

Not sure what this has to do with standby instruments. They will still be there.

doubleu-anker
6th Jun 2011, 16:06
ATC

" The New Zealand and Canadian approach is far superior."

You sure about that sport??

The NZ police are pretty damned quick to subpoena the CVR to assist them in prosecuting crews if there is an accident. The is not what the CVR is designed for IMHO.

Carjockey
6th Jun 2011, 16:22
will bet they will know for sure to the level that you can bet your life on the result.
If you want absolute certainty, then you are living in the wrong world

I already said there can be no certainty in this situation.

Are you 100% certain in your statements?

Carjockey
6th Jun 2011, 16:31
in accidents like these, there is a lot of contributing factors, neither of which could have caused the crash by itself. However, when they are working together, there is a synergy between them which leads to disaster. Even if you had all the data, you might not be able to tell if the crash really happened because of flying into thunderstorms, or pitot tube design, or lacking AoA indication, or excessive unmanageable automation, or lack of high speed, high altitude stall training/awareness, or something else. You can pick one reason and call it THE reason, but others will disagree with you, and the argument will just go on endlessly.


Well said! :D

Machinbird
6th Jun 2011, 17:04
Are you 100% certain in your statements?
100% certain doesn't relate to this world. Quantum mechanics and Schroedinger's Cat experiment tell us that.

Machinbird
6th Jun 2011, 17:11
JamesT73J,
Start at post #1395 and read forward.
That big screen may not be all it is cracked up to be, no matter what you put on it.

fireflybob
6th Jun 2011, 17:18
To an extent, are we training pilots too much?

Yes, of course, we need SOPs and structures, not to mention stall/upset training, in order to ensure safe flight but my perception is that rigid adherence to procedures is causing a mind set which sometimes doesn't perceive what is really going on.

The first step in solving any problem is the acquisition of the correct information - like, hey guys, something is happening here but what?

Carjockey
6th Jun 2011, 17:36
100% certain doesn't relate to this world. Quantum mechanics and Schroedinger's Cat experiment tell us that.


I see...

So would you consider your earlier statement:


I will bet they will know for sure to the level that you can bet your life on the result.
If you want absolute certainty, then you are living in the wrong world.


as 100% certain?

bearfoil
6th Jun 2011, 18:42
Some offshoots of the interminable discussion (guilty) are worthy to discuss in the absence of anything new. For instance, a question.

The "Yoke" is a LIE. No, it int. It may be a totem, but it is critical to team management. With the advent of the Sidestick, two questions became legend.

"What's it doing?" and, more critically, "What's HE doing". Neither is totally without basis, obviously.

A basic format poser. What is the Airbus Philosophy? How does it differ from other flight deck formats?

At a very basic level, the a/c is sold as single pilot, imo. Hence the lack of criticality of the PNF. Including the commander, who needs to supervise?

The Airbus cockpit has two managers, the others a manager and a manager/ Leader. In the case of 447, with Captain on deck, there were three managers.

A leader tells his men what he wants; a manager does also, but then he explains how to do it. The QRH, coms, and checklist can be done auto, either audio visual, or audio.

What's lost is the Command, and imaginative leadership.

With the a/c as a priori commander, there is no chain.

Training, Experience, Confidence, Imagination.

The PF needs to be able, Life or Death, to understand immediately what's happening. Not consult, scan, or be patient, waiting to be told, or worse, to guess.

Bonehead decision making is all around us, and any philosophy that does not support "ahead of the aircraft" 'gots', for whatever reason, will kill people.
Pilot on board or no.......

Machinbird
6th Jun 2011, 19:33
Quote:
100% certain doesn't relate to this world. Quantum mechanics and Schroedinger's Cat experiment tell us that.
I see...

So would you consider your earlier statement:

Quote:
I will bet they will know for sure to the level that you can bet your life on the result.
If you want absolute certainty, then you are living in the wrong world.
as 100% certain?Carjockey, you aren't showing your best side.

Good enough to bet your life on is not 100%. That doesn't exist in the real world.

When I drive to work, I know there is a real possibility of some other driver doing something that might kill me, but I don't stop driving to work.

Gorryd
6th Jun 2011, 21:18
I'm not a pilot but in my work I get in contact with different aspects of flying.

There are so many posts in this thread that I can't read them all. If what I'm going to suggest is mentioned in an earlier post I apologize.

Although I have never heard of it I wonder if in a stall situation like this there could be a phenomenon that could be characterized as a reversed elevator effect?

In this stall COP is obviously forward of COG and the horizontal tail must then produce a high lift (upwards) to rotate the nose downwards.

Hypothesis goes as follows. At this aoa plus the extra 13 degrees of the HT, the HT is probably stalled too. Pushing the sidestick forwards in order to gain more lift on the HT will move the trailing edge flap (elevator) of the HT downwards thereby giving the chord line of the HT a higher aoa resulting in deeper stall of the HT and less lift generated by it.

Pulling the sidestick backwards moves the trailing edge flap of HT upwards giving the chord line less aoa, a milder stall, more lift on the HT and a lower pitch angle.

If this hypothesis holds it could explain why the PF pulled on the sidestick

gums
6th Jun 2011, 21:43
@Gorry:

You are homing in on a theory several of us have expoused.

The Airbus stabilizer and elevators are "conventional". i.e. no all moving stabilizer as all military fighters have had since early 1950's. So your question is a good one.

Besides that, nobody here has yet to explain how the THS moves with respect to stick commands. I am waiting.

respectfully, from an old dinosaur FBW pilot

bearfoil
6th Jun 2011, 23:00
Here's more old fashioned stuff. When the conventional a/c (Airbus) is flying, it gets to change what is effectively the Angle of Incidence of the HS, but when the a/c gives it back to the pilot, he has to control Pitch with what amount essentially to "Trim Tabs" (elevators). Manually "trimming" the big slabs back to a neutral AOI, is an extra task to get the a/c back to "neutral".

No?

jcarlosgon
7th Jun 2011, 00:14
Gums, "Besides that, nobody here has yet to explain how the THS moves with respect to stick commands. I am waiting."

I’ll try:
THS moves by itself, both in normal or alternate law, in order to relief the force needed on the stick. If you pull it will move up, silently, and the other way around.
It freezes in certain conditions, below 100’ radio altitude, less than 0.5 G, high speed protection. It has limitations in its range, when AOA protection is active, bank greater than 33º, more than1.3 G, etc.
In direct law, it must be moved manually, by the manual pitch trim wheel, as the message Man Pitch Trim Only is shown on the PFD.
In normal and alternate law, it feels as if the aircraft is always in trim, as it should be. As thrust varies, both in A/P or manual flight, the trim wheel can be seen moving, compensating.
In direct law its manual use is easy, as the wheel does not move much, to go through the whole range.
AF447 should have had it available and moving forward if the stick had been moved forward and kept there for a certain time. It is necessary to force the nose down, and keep it there, if THS is already much too nose up and the aircraft pitching up.

HarryMann
7th Jun 2011, 00:24
When the conventional a/c (Airbus) is flying, it gets to change what is effectively the Angle of Incidence of the HS, but when the a/c gives it back to the pilot, he has to control Pitch with what amount essentially to "Trim Tabs" (elevators). Manually "trimming" the big slabs back to a neutral AOI, is an extra task to get the a/c back to "neutral".

To some extent, when having been handed back an aircraft under these conditions, especially in (!) heavy turbulence, wouldn't just flying it on trim-wheel in pitch be a) possible b) a good idea c) having first 'clocked' its position at handback.

This is presumably an elevator control setup that is = = stick fixed in pitch when flown hands-off? Yes?

bearfoil
7th Jun 2011, 00:50
I would think so, yes. Trim seems to be a counter intuitive goal when attempting a recovery? It implies that any particular attitude is worthy of continued authority. I am trying to picture how Trim is important to upset recovery (or in turbulence), when it is critical for allowing aft cg flight for economy? If relied upon to sustain an otherwise laborious aspect (tail 'lift'), it is also reliable to command inputs that may be more transient than the word 'trim' would imply?

Especially in recovery, as here with 447, with the THS NU within one degree of max., if the turbulence changes, one is stuck with max trim up. Just trying to get a handle on the challenges the PF was facing at a/p loss.

kappa
7th Jun 2011, 02:12
This discussion of analog vs digital instruments makes me realize that relatively soon there will be very few of us left who learned to fly with round dials and moving "hands" and "lines". The others will have no idea of what we are talking about.

I was recently shocked to find that a 12 year old neighbor, whose mother is a financial analyst and father is a lawyer, is unsure of the time when looking at a non-digital clock!

EGMA
7th Jun 2011, 02:58
I was recently shocked to find that a 12 year old neighbor, whose mother is a financial analyst and father is a lawyer, is unsure of the time when looking at a non-digital clock!..... that's why they shouldn't be allowed to breed ...


My definition of 'pilot error':-

(a) If the PF breaks the aircraft.

(b) If the PF attempts to fly through cumulo-granite, or a TS.

(c) If the PF stalls on approach, too low to recover.

However, if the PF (or the 'system') stalls the aircraft at altitude and can't recover because the controls won't respond or the instruments don't indicate a stall or the PF's training is lacking; then IMHO that is NOT pilot error.

Greek God
7th Jun 2011, 07:52
A couple of thoughts-

If icing was present as seems to be indicated to the extent it would affect the pitots then what would extensive airframe icing do to the AUW and was there any indication wing anti ice was being used?

Secondly I find it hard to reconcile being able to achieve a 7000fpm ROC in two and a half thousand feet from F350? Even if it was possible the ballistics and KE of a 205 ton aircraft going up at that rate would see it going quite a bit higher IMHO. In a light aircraft at lower levels it is extremely rare to see more than 6000fpm with a light aircraft never mind the pitch rate to achieve that ?

So maybe external forces were more of a factor.

Not sure Simulators would be able to accurately reproduce this situation with no empirical data.

HazelNuts39
7th Jun 2011, 09:34
If icing was present as seems to be indicated to the extent it would affect the pitots then what would extensive airframe icing do to the AUW and was there any indication wing anti ice was being used?
Secondly I find it hard to reconcile being able to achieve a 7000fpm ROC in two and a half thousand feet from F350?Clogging of the pitots is thought to be caused by ingestion of ice particles. At -40 °C there was no liquid water to cause icing of the airframe.

Increasing rate of climb to 7000 and back to 700 fpm is compatible with no more than about +/- 0.2 g.

BOAC
7th Jun 2011, 09:58
At -40 °C there was no liquid water to cause icing of the airframe.- incorrect. Liquid water can and does exist in the atmosphere at temperatures well below -40 as super-cooled water drops or normal drops carried aloft by rising air, hence the need to be aware of what is under you before you elect NOT to use engine anti-icing. The statement is a myth based on the meteorological fact that at temperatures below -40 air cannot normally contain significant concentrations of water droplets or water vapour.

rudderrudderrat
7th Jun 2011, 10:24
Hi BOAC,

I thought it was due to the "Latent Heat of Fusion" (enthalpy of fusion). Supercooled water droplets at -40 and below, will freeze on impact to form dry ice crystals(*) and hence won't stick. If you apply gentle heating, you may warm it into the wet range and it may stick (AF744 Pitot Problem?). If you apply loads of heat, it will remain wet and blow off.

(* I don't mean solid CO2)

lomapaseo
7th Jun 2011, 12:15
The super cooled stuff becomes a problem with small pasageways (probes) and small continuous sheds just big enough to bend the small compressor blade tips (sensitive internal areas of the engine).

The stuff on the wings (if it even sticks) is expected to shed (under air loads alone) often enough to not affect aerodynamics..

rak64
7th Jun 2011, 13:30
Liquid water can and does exist in the atmosphere at temperatures well below -40 as super-cooled water drops or normal drops carried aloft by rising air,

agree, moreover the gain of height (3000 ft) seems to little compared to the 7000 climb rate. May seen this as a sign of iced wings.
I do not see the need to hit the TC itself. To enter the cloud what is generated by the TC, containing huge amount of ice and supercoold liquid water is enough to overload the anti-ice capabilities of that aircraft.

matthewsjl
7th Jun 2011, 14:41
Secondly I find it hard to reconcile being able to achieve a 7000fpm ROC in two and a half thousand feet from F350? Even if it was possible the ballistics and KE of a 205 ton aircraft going up at that rate would see it going quite a bit higher IMHO. In a light aircraft at lower levels it is extremely rare to see more than 6000fpm with a light aircraft never mind the pitch rate to achieve that ?

I think we're getting a little fixated on the 7,000ft/min climb. That was reported by the BEA as the max rate of climb - we don't actually know if that was sustained for any length of time.

We know at 2h10m05s they were ate FL350 and at 2h10m50 were at FL375. So, that's actually less than a minute for a 2,500ft altitude gain. Overall, the rate must have been much less than 7,000ft/min for a good portion of that climb.

We also know there was nose-up sidestick but updrafts could have played a part too.

captplaystation
7th Jun 2011, 14:48
On 737 Classic & NG, Boeing procedures always stated that due to any moisture at less than -40c being "likely" to be in the form of ice crystals, it was not required to activate engine anti-ice when in climb or cruise with SAT < -40c, but still advised during descent (assumedly because you are descending into "warmer" air more likely to contain liquid moisture)
Boeing has recently released a bulletin (covering all types) which details incidents involving icing/surges/flameouts caused by these "safe" crystals forming ice on impact with engines (guess pitots would be something similar) but stops short of recommending activating TAI in climb/cruise when SAT < -40c.
I find this just a little ineffectual, surely if they are advising of a real risk, they should be at least recommending you disregard the <-40 exemption ? ? or am I missing something here ?

jcjeant
7th Jun 2011, 16:28
Hi,

Bodies recovery ended ......

7 June 2011 briefing (http://www.bea.aero/en/enquetes/flight.af.447/info07june2011.en.php)

Google Vertaling (http://translate.google.be/translate?u=http%3A%2F%2Ffr.news.yahoo.com%2Ffin-la-r%25C3%25A9cup%25C3%25A9ration-des-corps-du-rio-paris-140642218.html&sl=fr&tl=en&hl=&ie=UTF-8)

PARIS (Reuters) - Brazil's recovery off the bodies of victims of flight from Rio to Paris ended June 3 and the ship Ile de Sein, which was collected en route to France, said here Tuesday with the families victims.This scenario has led to conflicting interpretations between the company, the manufacturer of the aircraft and various experts. Air France insisted on the role of the failure of the Pitot probes, which resulted in the autopilot disconnect and loss of control associated protections.
.
But some pilots complain that the company not to have acquired a system called Buss (Back Up Speed ​​Scale) that would have allowed the aircraft to recover even in case of failure of the probes.
Experts close to Airbus stress, them, the mismanagement of the stall by the pilot.
I remember very well that Air France .. in their communications (before black boxes data released) insisted on the fact that failure of pitot was a factor but not essential
Seem's they have changed their song lyrics ....

jcjeant
7th Jun 2011, 16:52
Hi,

Between 1 h 59 min 32 and 2 h 01 min 46 , the Captain attended the briefing between the
two co-pilots, during which the PF said, in particular "the little bit of turbulence that you just saw
[…] we should find the same ahead […] we’re in the cloud layer unfortunately we can’t climb much
for the moment because the temperature is falling more slowly than forecast" and that "the logon
with Dakar failed". The Captain left the cockpit.At 2 h 08 min 07 , the PNF said "you can maybe go a little to the left […]". The airplane began a
slight turn to the left, the change in relation to the initial route being about 12 degrees. The level
of turbulence increased slightly and the crew decided to reduce the speed to about Mach 0.8.Psychology brief analysis of small events in the cockpit:
Is this the role of the captain to "attend" or instead (more logical in my view as he is the accountable commander) to "lead" the briefing ?
Why the PNF tell "maybe" ... he is affraid of the PF .. if he was more direct ?
Do the PF not see what action to take ?

FalcoCharlie
7th Jun 2011, 16:56
I find this just a little ineffectual, surely if they are advising of a real risk, they should be at least recommending you disregard the <-40 exemption ? ? or am I missing something here ?

Good point. I always turn on anti-ice even below -40 C when I see ice forming on the wiper blade.

The point made earlier about systems design error will be a central factor. There is no excuse for the stall warning not sounding all the way down to impact. That's why it is there. If both AOA probes show angle of attack past the stall it should sound period. Speed should have no effect on that. I think the effect of it not sounding led the pilots away from positively identifying the real problem.

I also take issue with the fact that there can be a stabiliser configuration that can keep the nose up into a full stall forever even if the engines are reduced to idle. But I am just a pilot and it seems I don't need to know of this until after somebody is dead.

I am all for round dials too, but I doubt anyone is listening...

TioPablo
7th Jun 2011, 17:40
IMHO a critical fault in “every” design is the tendency shown by “smart” ppl to disregard real life events and those which have to deal with it. Automation is just a tool; therefore it should be treated as what it is… Nothing more. Following that philosophy, the hammer should be in the hands of the carpenter and NOT the other way around… We already know that the FBW system isn´t as perfect as many would like it to be. I fully agree with TheShadow and his great post: #1222…

xcitation
7th Jun 2011, 18:23
The english translations of the original French BEA reports must be treated with caution. The BEA clearly states that the authoritative version is the original French copy.
That said it is interesting that the Capt was present for the bad weather briefing and then immediately left the cabin. IMHO seeing a solid wall of red on the weather radar at night is not boring and is not a trigger for taking a nap rest. Puzzling CRM.

GarageYears
7th Jun 2011, 18:28
I fully agree with TheShadow and his great post: #1222…

Then I fear you too are not prepared to READ the BEA note carefully and try to correlate what TheShadow asserts happen verses what is reported. The two DO NOT line up.

For one and very important point, TheShadow asserts that the aircraft was placed into the initial climb by the automation at drop out, but that is NOT what the BEA reports:

From 2 h 10 min 05 , the autopilot then auto-thrust disengaged and the PF said "I have the controls". The airplane began to roll to the right and the PF made a left nose-up input.

Since this simple statement is completely ignored (since it doesn't fit with the story TheShadow is telling), it follows that other salient and significant points are also misused or ignored to fit. It is true that the limited details we do have leaves much unanswered, but you can be pretty damn sure that the info we do have is correct and meaningful (least otherwise the wrath of the aviation community will descend on the BEA and all associated).

SeenItAll
7th Jun 2011, 18:34
jcjeant: I believe if you refer to the original French version, you will get a bit different nuance to these interactions.

While the English document says, "the Captain attended the briefing between the two co-pilots" the original French is "le commandant de bord assiste au briefing entre les deux copilotes." The verb "assiste" in French translates better into "participates." Thus, a better interpretation is not just that the Captain was present, but that he interacted as well. So although he may not have been the leader of the briefing, he was more than just a listener.

For the second phrase, the English document says, 'the PNF said "you can maybe go a little to the left […]".' But the original French says, 'le PNF propose "tu peux eventuellement prendre un peu a guache [...]".' I would translate this as 'the PNF suggests "you could go a little to the left"' which is a little more directive than "maybe."

While these alternative translations don't reverse the interpretation of what was going on, I think they suggest there was a bit less diffidence in the cockpit than is suggested by the English document.

Carjockey
7th Jun 2011, 18:36
However, if the PF (or the 'system') stalls the aircraft at altitude and can't recover because the controls won't respond or the instruments don't indicate a stall or the PF's training is lacking; then IMHO that is NOT pilot error.


Of course it's not.

An opinion:

Is that that there are basic software design misconceptions, with regard to the interface between humans (pilots) and the aircraft automation, built into certain commercial passenger aircraft. These misconceptions have been compounded and endorsed (perhaps in misguided good faith) by certain airline operators who believe that they can reduce their 'pilot training' costs by using aircraft that can 'fly themselves'.

These airline operators would have a philosophy something like this:

Why waste money on over-training pilots if the aircraft automation can handle the aircraft in flight? We can just train our pilots to fully believe in the aircraft automated systems can't we? The systems cannot go wrong can they?

But maybe they can...

This aircraft went down 3.5 minutes after the AP disengaged and handed control to the PF, without apparently giving any indication to the PF as to why the AP disengaged.

A supposedly highly sophisticated aircraft automation system just gives up in a flight situation which it cannot handle and gives control to the humans on the flight deck without any indication as to why it did this? WTF!

Is there an SOP for the pilots to deal with this situation?

If so, can the SOP be effectively executed in less than 3.5 minutes (or before the aircraft falls out of the sky) and if not, why not?

These questions really bother me.

I cannot imagine how those guys on the flight deck felt or what they thought when confronted with this situation, not to mention what the passengers/CC went through, if they were (God forbid) ever really aware of their situation...

So how about we take all the software writers who conceived this system, the beancounters who drove it's implimentation and the managers who approved it, put them all on the same type aircraft in a identical situation (with the managers in the drivers seats) and just say 'OK, you have control guys'...

jcjeant
7th Jun 2011, 18:42
Hi,

The english translations of the original French BEA reports must be treated with caution. The BEA clearly states that the authoritative version is the original French copy.
Voiçi la version française .....

Entre 1 h 59 min 32 et 2 h 01 min 46 , le commandant de bord assiste au briefing entre
les deux copilotes, au cours duquel le PF dit notamment que « le petit peu de turbulence
que tu viens de voir […] on devrait trouver le même devant […] on est dans la couche
malheureusement on ne peut pas trop monter pour l’instant parce que la température
diminue moins vite que prévu » et que « le logon a échoué avec Dakar ». Le commandant
de bord quitte le poste de pilotage.
A 2 h 08 min 07 , le PNF propose « tu peux éventuellement prendre un peu à gauche […] ».
L’avion entame un léger virage à gauche ; la déviation par rapport à la route initialement
suivie est d’environ 12 degrés. Le niveau de turbulences augmente légèrement et
l’équipage décide de réduire le Mach vers 0,8.So ,you can translate in english ...

The captain attended (assiste) the briefing
(the captain is there observing the discussion between the two pilots .. he don't take the lead of the discussion)
Or
J'assiste a un match de football
I attend a football match
Le verbe assiste n'a pas le sens d'assister en tant qu'aider
The verb has no meaning attends to attend as helping :)
EG:
Je t'assiste a lever ce meuble
I help thee to lift this furniture
Or
Je te porte assistance
I bring you support

If the captain is there for help it will be ...
Le capitaine apporte son assistance pendant le briefing
Captain assists during the briefing

Can you possibly or maybe (éventuellement) take a little to the left
(it's a proposition .. a polite suggestion .. he offer a choice to the PF .. it's not a order)

The sens of the sentences from french to english is exactly the same .......
The french language is full of words meaning the same thing ... c'est la finesse de la langue française :)

Turbine D
7th Jun 2011, 19:11
rgbrock1,

Sorry about that, try this link:

http://icingalliance.org/meetings/RIF_2009/documents/AIAA%20June%202009_Mason_version_nss.pdf

Level100
7th Jun 2011, 19:17
jcjeant,

with all due respect, but to my taste SeenItAll's perception of the appropriate french-to-english translation is better than yours.
secondly, the way the weather avoidance is phased is a GOOD example of CRM,
polite phrasing is an important part of the game.

jcjeant
7th Jun 2011, 20:27
Hi,

with all due respect, but to my taste SeenItAll's perception of the appropriate french-to-english translation is better than yours.Je ne pense pas que votre perception du français (qui est ma langue maternelle et paternelle :) ) ou celle de SeenItAll's est meilleure que la mienne.
Je ne suis peut-être pas un champion de l'orthographe ni sociétaire de l'académie française mais j'ai quand même quelques connaissances de la syntaxe ... :)

While the English document says, "the Captain attended the briefing between the two co-pilots" the original French is "le commandant de bord assiste au briefing entre les deux copilotes." The verb "assiste" in French translates better into "participates." Thus, a better interpretation is not just that the Captain was Le verbe assiste .. ne se traduit certainement pas pour le contexte dans lequel il est employé .. comme le fait de participer

Si vous assistez a un briefing ou si vous assistez a un tournois de tennis .. vous ne prenez pas part au briefing ou au jeu ... vous êtes juste un spectateur
Le BEA (en français dans le texte) emploie le verbe "assiste"
Si le BEA voulais que l'on comprenne que le Cdt était part active de ce briefing .. il aurais du employer le verbe "participe"
Si c'était vraiment cela l'intention du BEA ... le rédacteur de cette note doit revoir sa syntaxe .. car il induit les lecteurs en erreur

La bonne formulation:
Le Cdt participe au briefing avec les deux pilotes

Salutations.

PS:
Translation in english on request :8

EMIT
7th Jun 2011, 21:23
Answer to # 1473

On the subject of Engine Anti Ice below -40, or not: you will get your answer if you read the Boeing Bulletin.
Engine Anti Ice heats the cowl inlet lip and the spinner bullet nose. In that way, it prevents the build up of large chunks of ice, that may break off and damage compressor blades further down the engine. To be used in regions of supercooled droplets.
Ice crystal icing takes place inside the compressor section of the engine, there where Engine Anti Ice does not heat anything. So, turning on TAI below -40 serves no purpose. Ice buildup on cowl lip or spinner does not occur, because the ice crystals bounce off them.

In general.
On the subject of pitot icing: yes, it can happen, on Airbus as well as Boeing.
TAT probe icing happens as well, probably more often than pitot icing. It can be observed from the TAT anomaly phenomenon (again, read the Boeing Bulletin). For crystal icing to occur, you do not have to fly through any solid wall of red, just the light green outskirts will suffice.

On the subject of stall recovery - even when not stalled, when ever is 15 degrees nose up an appropriate attitude at FL 350 in a big lumbering airliner?

Chris733
7th Jun 2011, 22:00
After flying quite a few pure glass cockpits there is something very comforting about getting a purely analogue aircraft......

Turbine D
7th Jun 2011, 22:32
EMIT,

A very nice summary of engine anti-ice usage. The only thing I would add is the warm air used for the nacelle and spinner cone anti-icing comes from bleed air off the compressor. So if you use it when it is not needed, it hurts the overall engine efficiency.

TioPablo
7th Jun 2011, 23:06
"From 2 h 10 min 05 , the autopilot then auto-thrust disengaged and the PF said "I have the controls". The airplane began to roll to the right and the PF made a left nose-up input."


So... What would be the correct input (in your eyes), given an undesired roll-right (nose-down), event?
You prolly are aware of the term "Heuristics" and its relationship to "intelligent" software design...

lomapaseo
8th Jun 2011, 01:08
A very nice summary of engine anti-ice usage. The only thing I would add is the warm air used for the nacelle and spinner cone anti-icing comes from bleed air off the compressor. So if you use it when it is not needed, it hurts the overall engine efficiency.



Since spinner cones has turned up twice in this thread, how the heck do you plumb on-off bleed air into a spinning cone on the front of an engine?

FlamantRose
8th Jun 2011, 01:27
Entirely in agreement with jcjeant.
Le verbe "assister" ne signifie aucunement que le Cdb prend part à la discussion. Il est présent et entend l'échange entre les deux co-pilotes mais ne "participe" pas à cet échange. Il n'y a aucun doute la-dessus. Il n'est nulle part fait mention que le Cdb ait dit quoi que ce soit à ce moment là sinon il aurait pris part et donc aurait participé.

As for the second phrase "tu peux éventuellement prendre un peu à gauche" cannot be translated as "you could go a little to the left". The french translation of "you could go a little to the left" is " tu pourrais aller un peu vers la gauche". And that does not meet the original french wording. The meaning of the "eventuality" is left out.

Cela fait partie des nuances de la langue française.

Amicalement

RWA
8th Jun 2011, 04:21
Interesting article which calls attention to the Trimmable Horizontal Stabiliser having remained virtually at full nose-up from very early on; calling attention to the fact that the same thing had happened before, to an A320 near Perpignan in November 2008:-


One question lies with the trimmable horizontal stabilizer (THS). The critical phase of the flight, from autopilot disengagement to the crash, lasted 4 minutes 23 seconds. During the last 3 minutes 30 seconds, the position of the THS went from 3 degrees to 13 degrees nose-up and then remained unchanged. Yet, from about 2 minutes before the crash, the pilot flying switched to pitch-down inputs.

So, as French website aerobuzz.fr pointed out, why did the THS stay in such a nose-up setting? This may hint at the flight control law being no longer “normal” but in a mode (“alternate” or “abnormal”) where the autotrim function is deactivated. In that instance, the crew has to trim the stabilizer manually. In an A320 accident that took place near Perpignan, France, in 2008, the crew’s failure to recognize this situation contributed to the catastrophic chain of events. In the case of AF447, the crew did mention “alternate law” in the recorded conversation.


History of Flight AF447 Puzzles Experts: AINonline (http://www.ainonline.com/news/single-news-page/article/history-of-flight-af447-puzzles-experts-29974/)

Also found an article on the Perpignan accident. This confirms that the investigators determined that "a progressive pitch-up deflection of the horizontal stabiliser as the A320 decelerated" had contributed to the accident.

The investigators concluded that water in the AoA sensors (which they thought had probably been introduced by sloppy maintenance on the ground) had frozen at altitude and caused the malfunction:-


"With the workload mounting in the cockpit, because the aircraft was on approach to Perpignan, the low-speed test commenced. But the blockage of the angle-of-attack sensors resulted in an underestimation of the limit speeds for the A320's angle-of-attack protection.

"The crew waited for the triggering of these protections while allowing the speed to fall to that of a stall," says the BEA. It says this "passive" wait for the protective systems, a lack of awareness of the risks, and confidence in the operation of the aircraft's systems "tend to show" that the captain and the ANZ pilot started the manoeuvre as a "demonstration of the functioning" of the angle-of-attack protection "rather than as a check"."

Although the stall warning sounded, and the captain increased thrust and pitched the aircraft nose-down, the configuration of the aircraft - notably a progressive pitch-up deflection of the horizontal stabiliser as the A320 decelerated - and the failure to understand the jet's behaviour, resulted in the situation deteriorating and the crew's losing control of the stall recovery. All seven occupants were killed when the A320 struck the water, just 62s after the stall alarm.

Sensor icing caught out A320 crew in Perpignan crash (http://www.flightglobal.com/articles/2010/09/16/347457/sensor-icing-caught-out-a320-crew-in-perpignan-crash.html)

Mike-Bracknell
8th Jun 2011, 06:01
Forgive me for being an occasional 'dipper' into this thread (no time to read it and the others to completion) but has anyone overlaid the ACARS messages onto the BEA transcript yet to possibly point out what the aircraft thought it was doing whilst those in the cockpit were clueless?

cwatters
8th Jun 2011, 07:36
I'm not a jet pilot or engineer but..

Has the possibility of a fault with the PF stick been ruled out? Suppose that fault added a constant nose up. Presumably that would cause the THS trim to exagerate the problem? A stuck bit fault in a digital system can appear to add a constant to an otherwise correct value (eg it adds 1,2,4,8,16 etc) but you would hope error detection catches such faults.

Anyway Google finds..

Chapter 5. Flight controls (http://www.hursts.eclipse.co.uk/airbus-nonnormal/html/ch05.html#sidestick-transducer)

Airbus A320 Family Non-Normal Notes

5.19. Sidestick unannunciated transducer faults

It is possible for a failed sidestick transducer to cause uncommanded control inputs. If no fault is detected, the result is that the aircraft behaves as if that input had actually been made. Generally, the autopilot will disconnect and any attempt to control the aircraft with the failed sidestick will fail. The aircraft should be recovered with the other sidestick using the takeover button. Keeping this button pressed for 40 seconds will lock out the failed sidestick, and the autopilot can then be re-engaged. The autopilot should not be disconnected in the normal manner as pressing the takeover button will re-introduce the failed sidestick and the uncommanded input; use the FCU instead.

wiggy
8th Jun 2011, 08:06
whilst those in the cockpit were clueless?

I was going to say "ouch" but on second thoughts I take it you mean "clueless as to what it was doing"?

NigelOnDraft
8th Jun 2011, 08:10
This aircraft went down 3.5 minutes after the AP disengaged and handed control to the PF, without apparently giving any indication to the PF as to why the AP disengaged.

A supposedly highly sophisticated aircraft automation system just gives up in a flight situation which it cannot handle and gives control to the humans on the flight deck without any indication as to why it did this? WTF!

Is there an SOP for the pilots to deal with this situation?

If so, can the SOP be effectively executed in less than 3.5 minutes (or before the aircraft falls out of the sky) and if not, why not?

These questions really bother me.There is an SOP - it is quite simple:
PF flies aircraft and states I have Control.

It can, and should, be 'effectively executed' in <5 seconds. Priority #1 is flying (and Airbus philosophy) and far above discussion, let alone diagnosis, of "why" the AP disconnected. The reasons it can do so are numerous - and largely irrelevant at the time.

A supposedly highly sophisticated aircraft automation system just gives up in a flight situation which it cannot handle and gives control to the humans on the flight deck without any indication as to why it did this? WTF!A somewhat strange way of thinking :ooh: Even in an Airbus, at no point (that I can think of) is the aircraft AP system considered "more capable" by itself, without monitoring, than the Flt Crew. At no point are the crew absolved from monitoring the AP, and in the event they are not content with what it is doing disconnecting the AP and flying manually (albeit it may require a change in profile e.g. to a GA from a couple approach / autoland). In the same vein, the AP system is designed to disconnect itself (and warn the crew) as soon as it is "overloaded" / "confused" / being pushed outside it's "comfort zone"...

Basil
8th Jun 2011, 08:16
Pointed out to me by a private aviation group, interesting comment here. (http://www.avweb.com/news/avmail/AVmail_LettersToTheEditor_204773-1.html)
Credit AVweb.

AVmail: June 6, 2011

Letter of the Week: Airbuses Fly "Like a Video Game"

I would like to offer my comments and perspective with regard to the Air France Flight 447 accident. I have been a A-330 captain since 2003 and have over 4500 hours in the aircraft. While many A-320 pilots undoubtedly have more series time, I believe this probably makes me one of the most experienced A330 pilots in the world.

When asked how I like the aircraft, I tell people that there is likely no easier airplane to take over an ocean, and that the systems design and presentation is superb. That said, the automation is more complex and less intuitive than necessary, and the pilot-aircraft interface is unlike that of a conventional aircraft. Most important with regard to this accident is the fly-by-wire sidestick control. The sidestick itself has a very limited range of motion, making inadvertent over-control very easy. Of even greater significance, the stick itself provides no "feel" feedback to the pilot. That is, unlike a conventional aircraft, the pilot does not get a sense through pressure of how much input is being sent to the control surfaces. The most important advice I give to pilots new to the Airbus is to treat the aircraft not as an airplane, but as a video game. If you wait for the sidestick to tell you what you are doing, you will never get an answer.

Taking into consideration that Air France 447 was at FL 350 (where the safe speed envelope is relatively narrow), that they were in the weather at night with no visible horizon, and that they were likely experiencing at least moderate turbulence, it does not surprise me in the least that the pilots lost control of the aircraft shortly after the autopilot and autothrust disconnected.

Let's keep in mind that these are not ideal conditions for maintaining controlled flight manually, especially when faced with a sudden onslaught of warning messages, loss of autofllght, confusing airspeed indications, and reversion to "alternate law" flight control, in which certain flight envelope protections are lost.

A very bad Airbus design feature is thrust levers that do not move while in autothrust. They are instead set in a detent which would equal climb trust in manual mode. If the pilots did not reset the thrust levers to equal the last cruise power setting, they likely eventually ended up in climb power, making it difficult to reset the proper cruise power setting and adding to what was likely already a great deal of confusion.

But the real problem probably occurred immediately after the pilot flying grabbed the sidestick and took over manually. Unfortunately, airline pilots rarely practice hand-flying at high altitude, and almost never do so without autothrust engaged. As a result, we forget that the aircraft is very sensitive to control inputs at high altitude, and overcontrol is the usual result. Because the Airbus sidestick provides no feedback "feel" to the pilot, this problem is dramatically compounded in this aircraft.

I believe the Air France pilot grabbed the sidestick, made an immediate input (because as pilots, that's what we tend to do), and quickly became quite confused as to what the aircraft was truly doing. This confusion likely was exacerbated by fixating on airspeed indications that made no sense while trying to find a power setting with no airspeed guidance.

When transitioning from autopilot to manual control at altitude in the Airbus, the most important thing to do at first is nothing. Don't move a thing, and then when you do, gently take hold of the sidestick and make very small inputs, concentrating on the flight director (which, in altitude hold, should still have been providing good guidance). Of course, this is much easier said than done with bells and whistles going off all over the place, moderate turbulence and a bunch of thunderstorms in the area. As I said before, treat it like a video game.

So why did the Air France pilot find himself at the limits of sidestick travel, and then just stay there, maintaining a control input that simply could not logically be correct? When things go really bad and we are under intense pressure, it is human nature to revert to what we know from previous experience. Remember, the Airbus flies like no other aircraft in that the sidestick provides no feedback to the pilot. It is a video game, not an airplane.

I believe the Air France pilot unintentionally fell back on all of his previous flying experience, in which aircraft controls "talkedF" to him when he moved them. Distracted by many confusing inputs, he instinctively expected to be able to control the aircraft by "feel" while dividing his attention to address other matters. I've seen it happen in the simulator, and in an Airbus this is a sure way to lose control of the aircraft and is possibly the most dangerous aspect of Airbus design philosophy.

One last note: Airbus pilots often claim that the aircraft "can not be stalled." When the flight controls are in "normal law" this is a reasonably true statement. However, in "alternate law," as was the case here, stall protection can be lost. If we ever practiced this in the simulator, I don't remember it.

Lest anyone think I am blaming the Air France pilots for this accident, let me be clear. Despite all of my experience in the aircraft, I am not the least bit certain that I would have been able to maintain control under the same circumstances. I do feel certain that were you to spring this scenario on pilots in a simulator without warning less than half of them would have a successful outcome. Safely flying the 320, 330 and 340-series Airbus requires something of a non-pilot mindset.

Name Withheld

Editor's Note:

We have spoken with the writer of this letter to confirm his identity and honored his request for anonymity.

HundredPercentPlease
8th Jun 2011, 08:35
A supposedly highly sophisticated aircraft automation system just gives up in a flight situation which it cannot handle and gives control to the humans on the flight deck without any indication as to why it did this? WTF!

Carjocky, you are evidently not a pilot. But I will answer your concerns in case any other non pilots or journalists think your comments carry any credence.

Any autopilot/autothrust system needs inputs to work. If one of more of the required inputs are lost, it will stop working.

When the autopilot dropped out here it was clear to the pilots why it had dropped out, and it told them what control law they were now in. The PF verbalised the control law, and the reason for the autopilot dropout.

Flying without an autopilot is not a problem. Flying with unreliable airspeed is not a problem, and there is a QRH procedure to help you climb or descend, fly level and fly an approach. It doesn't take any time to "do" this procedure, since the first action for UAS in level flight is to do nothing - ie maintain the cruise pitch and thrust using manual controls. Unfortunately here the pilots for some reason (much debated and not yet understood) increased the pitch and stalled the aircraft. The exact details of the effect and strength of the turbulence is not yet known.

They then had to unstall the aircraft, with UAS. This, again, they failed to do as they did not reduce the pitch.

From the scanty information from the BEA, the only "surprise" from the aircraft was the lack of stall warning at very low speed. It might have been better if it was not suppressed, but to any pilot with more that 10 hours experience it should have been obvious that they were stalled. Quite why they did not see and correct the stall has yet to be explained - but there may well be more clues in the full report.

Level100
8th Jun 2011, 08:54
Chers
Flamant Rose et jcjeant,

I still am in disagreement with you:

Entirely in agreement with jcjeant.
Le verbe "assister" ne signifie aucunement que le Cdb prend part à la discussion. Il est présent et entend l'échange entre les deux co-pilotes mais ne "participe" pas à cet échange. Il n'y a aucun doute la-dessus. Il n'est nulle part fait mention que le Cdb ait dit quoi que ce soit à ce moment là sinon il aurait pris part et donc aurait participé.

Really, "assister" is not always employed in the restricted use you advocate. While I can agree with you for the assistance to a tennis-match, I do not definetely would agree for the assistance to a briefing.
That at least others have the same feeling like me (note my careful, polite and non-authoritive wordings in my initial post), I might be allowed to substantiate by showing an exerpt from the very first google answer to the meaning of "assister" and its translation :):

assister, verbe transitif
Sens 1 Secourir (http://www.linternaute.com/dictionnaire/fr/definition/secourir/), aider (http://www.linternaute.com/dictionnaire/fr/definition/aider/) quelqu'un (http://www.linternaute.com/dictionnaire/fr/definition/quelqu-un/). Synonyme secourir (http://www.linternaute.com/dictionnaire/fr/definition/secourir/) Anglais to assist Sens 2 Seconder (http://www.linternaute.com/dictionnaire/fr/definition/seconder/). Synonyme seconder (http://www.linternaute.com/dictionnaire/fr/definition/seconder/) Anglais to assist Sens 3 Être (http://www.linternaute.com/dictionnaire/fr/definition/etre/) présent (http://www.linternaute.com/dictionnaire/fr/definition/present/). Ex Assister (http://www.linternaute.com/dictionnaire/fr/definition/assister/) à (http://www.linternaute.com/dictionnaire/fr/definition/a-1/) un (http://www.linternaute.com/dictionnaire/fr/definition/un/) match (http://www.linternaute.com/dictionnaire/fr/definition/match/) de (http://www.linternaute.com/dictionnaire/fr/definition/de-1/) tennis (http://www.linternaute.com/dictionnaire/fr/definition/tennis/). Synonyme être (http://www.linternaute.com/dictionnaire/fr/definition/etre/) Anglais to attend
Note that the meaning that you state as exclusive (il n'y a aucun doute) even ranks only 3rd place.
Now, I also have looked in some old dictionaries (50 y), and, curiously enough, the
order is the other way around.

Given these facts we possibly could agree on the following
1) assister is a word for which the extent of its meanings has some leeway
2) this leeway apparently seems to change in time
3) most likeky the BEA-writer was not conscious about all this semantic issues this when he used the expression
4) and anyhow we do not know his own perceiption of our subject of discussion.

Bien Amicalement

jcjeant
8th Jun 2011, 11:23
Hi,

Given these facts we possibly could agree on the following
1) assister is a word for which the extent of its meanings has some leeway
2) this leeway apparently seems to change in time
3) most likeky the BEA-writer was not conscious about all this semantic issues this when he used the expression
4) and anyhow we do not know his own perceiption of our subject of discussion.

Bien Amicalement My last answer about this syntax thingh
The verb "assister" can indeed be understand .. have the meaning of help someone or the meaning of rescue someone .. etc ...
But as used in the stance of the BEA .. the meaning is the same than "assister a un tournois de tennis"
You can't help a "thing"
Briefing is a "thing"
Vous assistez a une chose .. a un spectacle .. a un évènement
Vous ne pouvez pas aider une chose .. un spectacle .. un évènement
Mais vous pouvez aider .. assister .. secourir une personne .. un animal
C'est juste une question de syntaxe .. le contexte dans lequel le verbe est employé
It's no in the BEA stance two ways meaning ... it's only one .. and it's "attend"
The BEA don't use the verb "assist"

3) most likeky the BEA-writer was not conscious about all this semantic issues this when he used the expressionIndeed and let me wonder if the mother language of BEA french note writer is the french language .... :8 as it's a gross syntax mistake (if his meaning was to write that the captain was there to give assistance to the two pilots at the briefing)