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RWA
12th Jul 2011, 12:47
Quoting Lonewolf_50:-


RWA, from the discussions over at tech log, Alpha Protect works in normal law.

Blowed if I know for certain, Lonewolf - I'd be surprised if even 'Bus-drivers' are absolutely certain, from the extraordinarily-complex documentation, what the systems may do or not do in different circumstances. But, according to this, in Alternate Law 'Alpha Floor' is lost, but AoA monitoring continues:-

http://www.smartcockpit.com/data/pdfs/plane/airbus/A330/instructor/A_0-Flight_Laws.pdf

Quoting EMIT:-


Remark EMIT: IF after all, the PF did not himself STEER the a/c into the zoom climb, then at least he should have seen the pitch change to 15 degr nose up, a very inappropriate pitch at that altitude, and should have tried to steer that pitch down to a normal value of 2 or 3 degrees above the horizon. This was not done, a lot of backstick was maintained.

I fear that you're now just making things up, EMIT. 'A lot of backstick' was not applied, leave alone 'maintained' - even the BEA states that the PF did exactly what he should have done, applied forward stick, controlled any tendencies to roll, and levelled the aeroplane out:-


"At 2 h 10 min 16, the PNF said "so, we’ve lost the speeds" then "alternate law […]". 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."

No 'backstick' at all?

iceman50
12th Jul 2011, 13:57
RWA

You are now the one making things up.

A lot of backstick' was not applied, leave alone 'maintained' - even the BEA states that the PF did exactly what he should have done, applied forward stick, controlled any tendencies to roll, and levelled the aeroplane out:-

Your previous quote from post 1994

"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. The stall warning sounded twice in a row. My bolding and colour change.

Pray tell why if the aircraft was in Alpha Prot it would increase the AOA by pitching UP!! Plus in ALT LAW 1/2 Alpha Prot is not available. Roll is direct which is why there could have been slight over-controlling in roll. High AOA and High speed protections could also have been lost. Once the AOA had been sensed greater than 30 degrees Abnormal Attitude Law would have been in place to allow recovery of the A/C. (Pitch control alternate law with no protections as mentioned before and Roll would now be direct - NO auto-trim from that point on and Manual Pitch trim required. This would be displayed on the PFD.)

You are like a dog with a bone and need to just relax and wait for further information to be given out by the BEA. With your continued misinformation and lack of understanding you seem to be trying to prove your own conspiracy theory.

Zorin_75
12th Jul 2011, 14:02
But, according to this, in Alternate Law 'Alpha Floor' is lost, but AoA monitoring continues:
See footnote 17: Protection totally lost if DUAL ADR failure or ADR disagree.
If there had been AoA protection we wouldn't have this thread.

cwatters
12th Jul 2011, 14:08
What speed does the "Low Speed Protection" kick in?

Edit: Ah i see footnote 18

"If dual ADR failure then low speed stability is lost"

bearfoil
12th Jul 2011, 15:50
A330 has a Horizontal Stabilizer.

It articulates, making it in essence also a variable incidence wing.

With aft fuel, the THS must work against its primary function, that of keeping the Nose UP.

If the THS AoA increases too much it will STALL

If it STALLS, the NOSE will drop like a stone, and the a/c will likely ROLL as well.

A pilot, seeing the NOSE DROP, and roll right. WILL INPUT NU AND ROLL LEFT.

IF Pilot overcontrols, the a/c will CLIMB, perhaps alarmingly, and said climb may become unrecoverable.

just a thought.

Lonewolf_50
12th Jul 2011, 16:15
RWA:
Based only on my understanding of the resource you cited, and a slightly dated training manual on the A330, the automatic feature (alpha protection) would induce control inputs (you could say "fight the pilot" or "help the pilot since what he's doing is heading in the wrong trend") in normal law, but in alternate law, that AoA related feature doesn't (should not?) do that. Stall warning should sound if the AoA is deciphered as a value approaching stall. (It appears that it did ... but also that there are some quirks at very low airspeeds regarding that feature).

What is frustrating in understanding this incident, for me, is the number of parameters that need both Airspeed and AoA as inputs, and the coupling of Airspeed to AoA, and problems this poses for the flight control system when those fundamental inputs are spurious or obviously erroneous, or "voted out." (Note: since the mishap was reported, there has been a Greek Chorus of pilots who point out that flying pitch and power is where one begins to deal with erroneous airspeed problems ... and there is also a considerable body of pilot experience that points to hand flying at altitude becoming a lost art ... )

Systems complexity considered, once in alternate law the speed protection can be overridden by pilot. Whether or not the computer sensed an overspeed protection requirement (and thus a kick off of the autopilot) has been discussed at some length. The consensus seems to be that AP kicked off due to crap airspeed inputs, not due to overspeed sensed (erroneously or otherwise).

As the bits and pieces of info come out of the investigating team, the discussion on Tech Log forum has been skeptical of initial (via the high speed protection feature?) NU input commanded by the robot. Part of the support for that skepticism has been the kinetic energy tradeoff (q) and the recorded pilots back stick inputs (along with roll inputs). These inputs look to have accounted for the pitch attitude and altitude gain (and of course, actual airspeed loss, versus displayed which was for a while all wrong).
High speed protection is active, depending on flight conditions, at / above Vmo / Mmo, and a pitch up load factor up to +1.75g is added to the pilot input when speed exceeds Vmo+6kt or Mmo+.01.
Speed is limited to Vmo+15kt or Mmo+.04 even with full forward stick.
If full forward stick is applied suddenly, speed is limited to Vmo+35 or Mmo+.07 and then returns to the above values.
The protection is deactivated when the speed returns to V/Mmo.
The AP will disengage if the high-speed protection is active.
In Alt 1 ... Above V/Mmo an over-rideable nose up demand is introduced. ... Alternate 2 Pitch control laws are identical to Alternate 1
Protections are as in Alternate 1
... in the case of failure of 3 ADRs, no high speed protection.
What I glean from this is:
if all three of the sensors that feed airspeed info to the flight computers and displays went pear shaped -- the evidence points to this based on pitot icing -- then the automatic pitch up would NOT happen since in Alt 2 that feature is disabled. This presumes that the flight computers more or less were functioning as advertised.

Whether or not a suprious voltage or oddball computer decision entered into this cannot be known as of today. It may be unknowable, if such transpired. There does not seem to be much of any evidence to support that class of malfunction. If such did happen, it didn't leave much of an audit trail.

Svarin has made some thought provoking posts and analysis in that regard, recommend taking a look at his inputs if you have not already.

Cheers

bearfoil
12th Jul 2011, 16:33
Lonewolf50

From the outset and per BEA the PF made one NURL at a/p drop. It was not continuous. The climb is unexplained, although High speed Prot is a candidate, certainly.

Lonewolf_50
12th Jul 2011, 16:49
Thanks bear, I just read PJ2's latest Tech log post on how much SS deflection it takes to start a climb. He related to about six inch control deflection on a yoke controlled jet. Most enlightening. Also the deciphering of the BEA reports on when the inputs to the nose began to drive the nose higher, in concert with TOGA. Paints a different picture.

I think it well to bear in mind that, per the basic systems information publicly available, unless you counter any nose up input you makes on the SS, your nose up input remains within the system.

Put another way, if you put a little nose up in, you need to take the same amount out to restore level flight, unless you are attempting to trade airspeed for altitude. As I understand the Law they were in, (Alternate) the computer won't think through that for you. You must mind your pitch attitude and counter correct for your various inputs.

More than one pilot who flies at high alt has pointed out to how delicately one must handle the big jets at high Mach numbers and high altitudes. Hand flying. (Seems to require some practice to master, like any sort of flying).

If I misunderstand the controls, please correct me.

bearfoil
12th Jul 2011, 17:30
Yes. And NO. In a powered system, especially one with a tagalong "Trimmer" (also described as a variable incidence wing set), it is a bit more complicated? "Stop the Roll". "Relax back stick".

Ab initio complaints from the CFI? Once rolling an A330, or Pitching it, with a "helper" as big as my house, the Physics is different? Not really, perhaps surprising is more accurate.

IF PF's first NU was in some way additive to an existing rotation of some description, it explains a bit how the rotation could have been emphatic enough to elicit 7kfpm? If he held it enough (before the seat started to really push him up!) to allow that big slab to acquire the power to really move her tail, Bob is then someone's uncle........?

The BEA later mention "repeated ND inputs" by the Pilot, but have they attached these to an attempt to recover from the climb? BEA's bon mots need to be sorted by time on a linear graph, perhaps that is forthcoming.

Lonewolf_50
12th Jul 2011, 20:30
Yes. And NO. In a powered system, especially one with a tagalong "Trimmer" (also described as a variable incidence wing set), it is a bit more complicated? "Stop the Roll". "Relax back stick".
Not quite as simple as "relax back stick." That leaves the "up" command in place. Worth reviewing the on line resource, A330-A340 Flight Crew Training Manual . pdf. (Dated, June 2005) regarding SS and high speed protection, if Alpha Prot isn't working. (Seems not to have been, else no stall, right?).
See pages 27 and page Page 34 of that .pdf.

Note: pull side stick up, release. Nose stays up, up you go. Push side stick forward, and then release, to change pitch. If you don't, up you will keep going ...

IF the magnitude, in displacement and time, of your nose up command isn't equaled by the magnitude, in displacement and time of the nose down command, THEN your nose will stay more "up" than "level." (See the pictures).

I have been intrigued by the discussion about what happened deep into the event, when the AoA had gone high, plane was falling, and questions on control effectiveness in well developed stall arise. But we are not talking about that time, the concern at hand is upset initiation.

I honestly don't think it's that complicated.

The complexity begins when one sorts through laws that rely on the AoA input, and Airspeed inputs, and being aware of which law is operating. Some of the laws do some work for you. Some hundreds of posts into this discussion, we have the pilot's own words to tell us which law state to examine: alternate law. Fewer things at work for you.

I'll await further input in re Abnormal Attitude law. Some parameters were met. But some information (leaks?) to date suggest that due to airspeed being erroneous, AA not in play. I hope that gets officially addressed.
Ab initio complaints from the CFI? Once rolling an A330, or Pitching it, with a "helper" as big as my house, the Physics is different? Not really, perhaps surprising is more accurate.
Zero-value-added prose. :confused:
IF PF's first NU was in some way additive to an existing rotation of some description, it explains a bit how the rotation could have been emphatic enough to elicit 7kfpm?
Based on what data point? Were there an already existing rate of climb in progress, do you not think the FDR would have that data, and the info be part of the summary?
If he held it enough (before the seat started to really push him up!)
Do you mean "if he had held nose down" enough? Seat push him up? What means this?
to allow that big slab to acquire the power to really move her tail, Bob is then someone's uncle........?

Zero value added, though droll. :cool:

As you slow down, the magnitude of force acting on your airfoil reduces as square of the velocity change. Does one get to a point of lost control effectiveness? Good question.
The BEA later mention "repeated ND inputs" by the Pilot, but have they attached these to an attempt to recover from the climb? BEA's bon mots need to be sorted by time on a linear graph, perhaps that is forthcoming.
One certainly hopes for more clarity in the next report.

bearfoil
12th Jul 2011, 21:10
Howdy lonewolf.

The "relax back stick" I qualify in the next phrase "ab initio commands from CFI?"

It is elementary in a cessna. Not so in a big rig.

I've lost [QUOTE] function, so to answer "what data point"? I would say:

Unable. If it's there, BEA have NOT stated it. Simply because we want to believe, we do. Why? Can I say for certain the a/c was not trending in rotation UP? Simply because it is not included? PF input NU and Roll Left. From BEA, we see it everywhwre. Supposedly as his first action after "I have the controls". Is it? Really? In the DFDR, did PF start with a clumsy grab at the Stick after a/p drop, and input NDRR? Was he recovering from his own mistake? No?

BEA will (IS?) living to regret the accommodation it made to Airbus. They must reveal more, and then more, each time stopping unsatisfactorily with "Wait for the final Report".

TioPablo
13th Jul 2011, 02:29
RWA, from the discussions over at tech log, Alpha Protect works in normal law. At some point early in the AF 447 event, the pilots reported alternate law. At that point, Alpha Prot should not have been a factor in the behavior of the aircraft.I would say... Next time: make a big glider of it... Without any doubt.

xcitation
13th Jul 2011, 16:24
Bearfoil
From the outset and per BEA the PF made one NURL at a/p drop. It was not continuous. The climb is unexplained, although High speed Prot is a candidate, certainly.

The report does not explicitly say how long the nose-up input was. IMHO it was continuous from 2h 10 min 05 "...nose up input." until 2 h 10 min 16 "...nose-down control inputs". At most this was for 11 seconds and resulted in the climb from FL350 to FL375 which sounds reasonable.
We can speculate if/why the PF intentionally made the climb as he did not adjust the thrust during the change in FL despite announcing he had control before the manouver. This initial nose up would appear to be counter intuitive given the stall warning and desire to maintain cruise altitude. Unfortunately the IAS on the right PFD used by PF was not recorded on the FDR. Did the ADIRUs give bogus attitude indications? It would explain the bizarre "inputs made by the PF were mainly nose-up".

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. 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).

Note 1: Only the speeds displayed on the left PFD and the ISIS are recorded on the FDR; the speed
displayed on the right side is not recorded.

Note 2: Autopilot and auto-thrust remained disengaged for the rest of the flight.


At 2 h 10 min 16, the PNF said "so, we’ve lost the speeds" then "alternate law […]".

Note 1: The angle of attack is the angle between the airflow and longitudinal axis of the airplane.
This information is not presented to pilots.

Note 2 : In alternate or direct law, the angle-of-attack protections are no longer available but a
stall warning is triggered when the greatest of the valid angle-of-attack values exceeds a certain
threshold.

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.

Lonewolf_50
13th Jul 2011, 16:31
@ xcitation

From the outset and per BEA the PF made one NURL at a/p drop. It was not continuous. The climb is unexplained, although High speed Prot is a candidate, certainly.

FWIW, that quote isn't from me, it's from bearfoil. :cool:

The report does not explicitly say how long the nose-up input was.

Indeed, which leaves one wanting in terms of understading PF actions.
IMHO it was continuous from 2h 10 min 05 "...nose up input." until 2 h 10 min 16 "...nose-down control inputs". At most this was for 11 seconds and resulted in the climb from FL350 to FL375 which sounds reasonable.

Ten seconds of nose up input. Continuous or intermittent? :confused: If continuous, that's quite a bit of nose up).
(What can you do with ten seconds of sustained "nose up" command in a given aircraft. ) Well, in a small plane, I could loop a T-28 in around ten seconds of continuous nose up (pitch toward stomach) input (a 3.5 g maneuver) back when the earth was nearly new ,and I was learning to fly. :cool: I doubt AF 447 pitch input was anywhere near 3.5 g, heck, the acft control system is limited to 2.5 g pull.

Unfortunately the IAS on the right PFD used by PF was not recorded on the FDR. Did the ADIRUs give bogus attitude indications? It would explain the bizarre "inputs made by the PF were mainly nose-up".
Aye. thanks.

goldfish85
13th Jul 2011, 21:53
Quote:
"The cases are completely different."
It is a remarkable coincidence that both zoomed at 4.2 deg AoA

RWA
14th Jul 2011, 03:12
Quoting excitation:-

The report does not explicitly say how long the nose-up input was. IMHO it was continuous from 2h 10 min 05 "...nose up input." until 2 h 10 min 16 "...nose-down control inputs". At most this was for 11 seconds and resulted in the climb from FL350 to FL375 which sounds reasonable.

None of the mentions of 'inputs' record the length of any of the inputs, excitation? However, the context - particularly the fact that the BEA note does not go on to record any climb, but instead quotes the PNF talking about the speeds - strongly suggests that the PF achieved his object (corrected the roll and duly levelled out). I've only flown light stuff (mainly gliders, as it happens :)) but even I know that a roll tends to produce less lift from the wings, so that a touch of 'up elevator' is often required to maintain altitude when recovering from an uncommanded roll?

And further, had the PF kept the 'noseup' on, I can't imagine ANY aeroplane taking 11 seconds to respond? Or, if any do, I wouldn't want to fly on them? :)

"Unfortunately the IAS on the right PFD used by PF was not recorded on the FDR."


I believe that normal practice is for the senior first officer (and therefore PIC while the captain is on his break) to remain in his accustomed righthand seat. This is supported by the BEA quoting the captain as saying, "He's taking my place"?

"Did the ADIRUs give bogus attitude indications?"

Now that's a heck of a good question! And it caused me to look back at a summary of all those 24 ACARS messages. And yes, all three ADIRUs appear to have reported problems simultaneously:-

"34123406IR21,EFCS1X,IR1,IR3"

Looking further, I found something I'd missed earlier - even ISIS, the standby instrument system, appears to have reported problems too:-

34220006ISIS 1,,,,,,,ISIS(22FN

There's an analysis of all the messages below. I can't vouch for its accuracy, but if it IS accurate, and the pilots were presented with a mass of instruments that were either blanked out or reading wrong, the BEA (which only listed the ACARS messages in its first report, without any explanations, and didn't mention them at ALL in the note) is going to have a helluva lot of explaining to do one of these days........

http://www.iag-inc.com/premium/acars2.pdf

EMIT
14th Jul 2011, 14:00
From where suddenly come the ideas that the attitude indicators were giving false indications? Wouldn't such a thing, massively important, have been reported in the BEA note?

The "failures" that are distilled from the ACARS messages have been explained a long time ago: systems report OWN failures, but also failures FROM OTHER SYSTEMS, with whom they communicate. Because of that setup, you may encounter the system identifiers IR1, IR2 and IR3 in situations where,e.g. the Air Data units are faulty.

RWA
14th Jul 2011, 15:07
Quoting EMIT:-


"From where suddenly come the ideas that the attitude indicators were giving false indications?"

In my case, from the very first press reports on the accident, plus subsequent amplification?


"Wouldn't such a thing, massively important, have been reported in the BEA note?"

You'd have thought so, wouldn't you? But the note doesn't mention it at all. And all the original BEA interim report said about them was, basically, that they aren't supposed to have anything to do with any investigation :):-


twenty-four automatic maintenance messages were received between
2 h 10 and 2 h 15 via the ACARS system. These messages show inconsistency
between the measured speeds as well as the associated consequences.

1.16.2.5 Partial conclusion
At this stage of the investigation, the messages analysed allow us to conclude
that various monitoring processes were triggered. At least one of them
corresponds to an inconsistency in the speed measurements. Several of the
cockpit effects messages recorded could correspond to the consequences of
these monitoring processes:
AUTO FLT AP OFF,
AUTO FLT A/THR OFF,
AUTO FLT REAC W/S DET FAULT
F/CTL RUD TRV LIM FAULT,
F/CTL ALTN LAW,
FLAG ON CAPT (F/O) PFD SPD LIM,
FLAG ON CAPT (F/O) PFD FD.
Note: the CFR was designed to facilitate maintenance operations; it is therefore not
intended to be used for investigation purposes.



"The "failures" that are distilled from the ACARS messages have been explained a long time ago....."


Fine then - apologies, I must have missed it. Please post a link to the 'explanation' you're referring to?

xcitation
14th Jul 2011, 15:08
EMIT


Attitude

From where suddenly come the ideas that the attitude indicators were giving false indications? Wouldn't such a thing, massively important, have been reported in the BEA note?

It would be remarkable I agree. I am trying to explain why would the pilots maintain a generally nose up attitude for 4 minutes of stall descent. There are many possibilities. I find it incredulous that all 3 simply forgot basic stall recovery. IMHO either they ignored the instruments or the instruments failed or both.

The "failures" that are distilled from the ACARS messages have been explained a long time ago: systems report OWN failures, but also failures FROM OTHER SYSTEMS, with whom they communicate. Because of that setup, you may encounter the system identifiers IR1, IR2 and IR3 in situations where,e.g. the Air Data units are faulty.

But did it record every failure? e.g. do we know what the right PFD showed for speed. It should be noted that in other A330 incidents false stall warnings have been generated and in those occasions correctly ignored. Could this be why they ignored most of the stall warnings?

Note 1: Only the speeds displayed on the left PFD and the ISIS are recorded on the FDR; the speed
displayed on the right side is not recorded.

jcjeant
14th Jul 2011, 15:40
Hi,

Can I suggest that if all participants in this theater were all together in the cockpit of the 447 the night of the event .. the end of the flight would be the same (splash) :confused:

Lonewolf_50
14th Jul 2011, 16:08
jc, it would be so crowded in that cockpit nobody would be able to see, or move. Picture a phone booth and a bunch of college students trying to set a record of how many men one can stuff into one. No way to read the PFD, for one ... :p

EMIT
14th Jul 2011, 17:17
Quoting RWA
"In my case, from the very first press reports on the accident, plus subsequent amplification?"
Unquote
SIGH

Wouldn"t BEA Interim report 1 and 2 be a better source of information?
Quoting BEA Interim reports 1 and 2:
"twenty-four automatic maintenance messages were received between 2 h 10 and 2 h15 via the ACARS system. These messages show inconsistency between the measured speeds as well as the associated consequences,"
Unquote

Nowhere is there a mention of ATTITUDE information problems.
Do not mislead yourself by thinking that FLAGS on the PFD mean that there is a problem with ATTITUDE INDICATION. An FD flag means, NO FLIGHT DIRECTOR, an FPV flag mean NO FLIGHT PATH VECTOR, etcetera.
The PFD in fact is a display that combines MANY flight instruments and annunciations in one display screen. The attitude instrument has not been reported as faulty in any way.
Have a look at Interim report 2, page 36 and onwards (pdf page numbering, otherwise page 35 and onwards, if you look at the report numbering - the pdf counts the cover page as a page, the report text doesn't). Report can be found on the BEA site.

Attitude indications are compared (by a COMPARATOR) between the three Inertial Reference Units. Absence of any ATTITUDE FAILURE indications mean, with a fair amount of certainty, that there were no problems with the ATTITUDE INFORMATION.
That the aircraft somehow ended up in a problematic attitude, 15 degrees nose up above FL350, is a completely different subject.

On page 48 (pdf count) of mentioned report, you find an illustration of a PFD with failure flags - in that picture, you have a completely functional attitude indication, any pilot should be able to work with that, and see through the multitude of failure flags.

before landing check list
14th Jul 2011, 17:17
So, did it crash because the system allowed most if not all data to the pilots to be false in this situation?

Is it a good thing that when you want to input a control movement you are in essence asking a computer permission, and if permission is granted it may or may not be exactly what you thought you wanted. (For you and your passengers own good of course)

Is our own training lacking in some way? Are we getting away from the basics and if we are is it a step in the right direction?

The "failures" that are distilled from the ACARS messages have been explained a long time ago: systems report OWN failures, but also failures FROM OTHER SYSTEMS, with whom they communicate. Because of that setup, you may encounter the system identifiers IR1, IR2 and IR3 in situations where,e.g. the Air Data units are faulty.

Is the system overall so complicated that a mere human cannot fully comprehend all of the scenarios thrown his way and if so what are we doing in the cockpit anyway? We are safety pilots for what?

Are we so far ahead of the game that we have lapped ourselves and now behind again?

Hi,

Can I suggest that if all participants in this theater were all together in the cockpit of the 447 the night of the event .. the end of the flight would be the same (splash)

I would like to think that this very moment those pilots are satisfied that they know they did everything correctly and to the extent of their abilities and it was the system that let them down.

xcitation
14th Jul 2011, 17:57
EMIT (or anyone else willing to stick their neck out)


Reasons Why "Generally" Stick Back for Final Mintues?

Failure to recognize stall condition (PF responded correctly to the first stall but not subsequent stall).
Correcting for perceived overspeed/dive.
Ignored flight attitude data.
THS trim interferance?
Pilots executed wrong stall recovery procedure although they did it right the first time ???
Failed flight attitude data on PFDs, no backup steam guage style AI instrument installed. [A330 ADIRU failures: 21 May 2009 Miami-Sao Paulo TAM Flight 8091 registered as PT-MVB and on a 23 June 2009 Hong Kong-Tokyo Northwest Airlines Flight 8 registered as N805NW]
Sidestick input fault with nose up bias. Failure to diagnose and overide.

EMIT
14th Jul 2011, 18:02
xcitation

Your numbers 1 (excluding bracketed text) and 3 score high on my shortlist.

Zorin_75
14th Jul 2011, 18:13
So, did it crash because the system allowed most if not all data to the pilots to be false in this situation?
Perhaps it's time to revisit the Bea note:

2 h 10 min 05: (...) 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).

2 h 10 min 16: (...) The speed displayed on the left side increased sharply to 215 kt (Mach 0.68).(...)

2 h 10 min 51: (...) Around fifteen seconds later, the speed displayed on the ISIS increased sharply towards 185 kt; it was then consistent with the other recorded speed.
(...)
Note: The inconsistency between the speeds displayed on the left side and on the ISIS lasted a little less than one minute.

From all we know, they temporarily lost airspeed.

Is it a good thing that when you want to input a control movement you are in essence asking a computer permission, and if permission is granted it may or may not be exactly what you thought you wanted. (For you and your passengers own good of course)
At which point do you suggest the plane didn't do what the pilot asked from it because of the FCS?

Is the system overall so complicated that a mere human cannot fully comprehend all of the scenarios thrown his way and if so what are we doing in the cockpit anyway?
EMIT was talking about Acars messages. They're used to confuse technicians, not pilots...

TioPablo
14th Jul 2011, 20:37
IMHO, pilots didn´t fail to recognize their compromised situation.
Rather, I think they were dealing with a confused system, which missed the right
"law" switch or state change to begin with!
Bad training (read = arrogant position taken by manufacturers and company policies), contributed for sure!
The training based on following automatics improved the waste of time, wich at the end killed them all.
When the Captain reentered the cockpit the power plant was set at idle and nose-down inputs were fed...
So: Why?
Why power idle and change of pitch?

Well, I think they knew (or the Captain did), the best way to make a compromise with the (for them unkwon), airspeed was to make a glider of the aircraft.
Going back to the basics thus...
They just missed the Trim Wheel... And when they were on the right path to solve the problem, automation began blaring stall and confused them even more...
Who knows... Maybe it was far more worse than we can imagine...
I my eyes they knew their status, only FL370 is way to short to react well when your rate of descent is 10K feet/m.

And... If I had been a pax on AF447, sure I had tried, crawled on the roof if needed, with all the negative g´s on my ass to the cockpit to tell the pilots they had to decrease their AoA as soon as they could...

bubbers44
14th Jul 2011, 22:35
When the AP and AT failed would the plane have just flown straight and level with the last power setting before it disconnected? If there was an erroneous overspeed would the disconnected AP pitch up?

My neighbor says the Airbus autopilot is on even when disconnected to maintain pitch and bank. I recall it being brought up a few hundred posts ago so sorry if this has been hashed out before. I had another arguement with him last night because he said if the AP is off it is still flying the airplane using your control stick inputs. I said if you can get out of your seat and go in the back how can you say the AP is off. It might be in the basic CWS mode of the Boeing but for that you need the AP on.

mm43
15th Jul 2011, 00:17
bubbers44;
if the AP is off it is still flying the airplane using your control stick inputs.This is what was meant:-

http://oi53.tinypic.com/ok0486.jpg

FullOppositeRudder
15th Jul 2011, 01:13
Can I suggest that if all participants in this theater were all together in the cockpit of the 447 the night of the event .. the end of the flight would be the same (splash) and then:

jc, it would be so crowded in that cockpit nobody would be able to see, or move. Picture a phone booth and a bunch of college students trying to set a record of how many men one can stuff into one. No way to read the PFD, for one Hypothetically it may just have made the difference needed for a different outcome and in a manner not envisaged so far.
The CG of the aircraft (which seems to have lost pretty well all means of aerodynamic and control authority) would have been brought forward to the degree that the seesaw effect might cause the nose to drop to the point where the aircraft starts to move forwards again. Effective airspeed would be recovered and a faint hope for resumption of normal flight presented. It wouldn't be pretty or pleasant and the end result may well have been the same.

All hypothetical of course. :8

before landing check list
15th Jul 2011, 02:46
At which point do you suggest the plane didn't do what the pilot asked from it because of the FCS?

There was that A320 that flew into the trees after the pilots performed a low pass...


EMIT was talking about Acars messages. They're used to confuse technicians, not pilots...

Mine was strictly a rhetorical question.

Zorin_75
15th Jul 2011, 07:02
There was that A320 that flew into the trees after the pilots performed a low pass...
Without going into another of those discussions, where do you suppose might be parallels to AF447 (besides an A plane being involved)?

Mine was strictly a rhetorical question
I know. But is some internet experts getting Acars messages wrong a good case in point for your answer?

before landing check list
15th Jul 2011, 13:34
Without going into another of those discussions, where do you suppose might be parallels to AF447 (besides an A plane being involved)?

Both flights utilized an aircraft that was strictly FBW. All I am saying in general the system is designed to fly the aircraft better then the pilots and tell me if I am wrong here but it does have the capability to negate pilots actions. (The friggen A320 in the trees) I was not aboard flight 447 and neither were you so I do not know if there was an exact parallel however you are still controlling (somewhat) a system that is controlling the aircraft. Remember the designers have designed the system to be better then you and in doing so gave the system (whether inherent or by design) the ability to override what you ask of it. It knows best right? And I do think in a lot of cases it probably does know best since a lot of the pilots now have limited flying skills. But there is going to be that one hundredth of one percent that the software designer did not cover or the friggen hardware craps out and you you have between your hands and the control surfaces are some useless wires.
I like automation, with it I can relax a bit and in doing so I can better see the big picture. Hand flying at flight level does suck. (I flew cargo so yes we tried it on occasion) Are you totally comfortable of not have 100% control of the aircraft? I do stand by my original statement though; I do not mind FBW as long as the wires are in control tubes.

I know. But is some internet experts getting Acars messages wrong a good case in point for your answer?

I do not fully understand your question (Or is it a statement with a question mark?) I am not an "internet expert" nor am I am expert in flying. I have been flying professionally since 1982, a healthy mix of military, law enforcement and commercial and presently instructing in the desert. So I have almost 30 years of experience, most of which have been successful, have not killed anyone by accident and not bent any sheet metal.
I am not here to compare experiences, time, licenses, type rating anything with you nor do I need to. I have not met any aircraft that can read whats is on the back of my piece of plastic. Well maybe your FBW one can. There is nothing (yet) that can replace experience and sound judgement. I am just giving my opinion.

RWA
15th Jul 2011, 15:15
(quoting 'before landing checklist':-


Remember the designers have designed the system to be better then you and in doing so gave the system (whether inherent or by design) the ability to override what you ask of it. It knows best right?

And I do think in a lot of cases it probably does know best since a lot of the pilots now have limited flying skills.


From much less experience, 'before landing checklist,' in my personal experience as a mere amateur flyer, I couldn't agree more. Both main manufacturers and the airlines are leaning more and more towards a situation where the 'systems' hold sway and the pilots are virtually forbidden to fly manually, unless they take the risk of being charged with anything from 'gross negligence' to 'manslaughter' if anything goes wrong.......

It's worth bearing in mind, too, that the 'first duty' of flightcrews nowadays is 'listening to the systems.' Someone above mentioned that the AF447 pilots shouldn't have taken as much as ten seconds or so before reacting to the 'zoom-climb' - it's fair to say that, as far as I know, the flight-crew's first duty would have been to 'plough through' all the error messages, one by one, with the PNF reading them out and the PF acknowledging and clearing them, before they actually DID anything about them.......

Sadly, I suspect that when (and if) the BEA finally comes clean and publishes the full CVR transcript, we'll hear that the flightcrew literally didn't live long enough to get through 'tic-tacking' on all those messages.......

My own view is - and always has been - that the pilot should always have the final say. And, further, that if a given aeroplane can't be safely flown manually in all conditions, the answer is not to install yet more 'systems' but to 'design the b****y thing so that it works properly......'

One Outsider
15th Jul 2011, 16:58
I couldn't agree more. Both main manufacturers and the airlines are leaning more and more towards a situation where the 'systems' hold sway and the pilots are virtually forbidden to fly manually
Nonsense. 'Systems' are there to be used by crews when appropriate just as manual flying is when appropriate.

It's worth bearing in mind, too, that the 'first duty' of flightcrews nowadays is 'listening to the systems.
Wrong. The 'first duty' of crews is to fly the aircraft. Whether that is done manually or via the 'systems' you tell the aircraft what you want and then monitor the response.

it's fair to say that, as far as I know, the flight-crew's first duty would have been to 'plough through' all the error messages, one by one, with the PNF reading them out and the PF acknowledging and clearing them, before they actually DID anything about them.......
Then you don't know very far. The 'first duty' of any crew is to fly the aircraft. Any other actions are secondary and are to be performed when not interfering with flying the aircraft.

Being a mere amateur you are perhaps excused, but with the amount of nonsense already posted there is no need to add more.

One Outsider
15th Jul 2011, 17:25
Something

Zero-value-added prose, as someone already noted before.

Henri737
15th Jul 2011, 18:24
Despite all the more than 100 pages with remarks and replies: still asking myself: why did they fly into a level 5 CB? What radarsystem was in this aircraft?

In a CB you can expect anything, so how the aircraft behaved could have been far beyond its design-limits.

wallybird7
15th Jul 2011, 21:01
Why the zoom climb?

It's very odd to me that all of the blogs seem to overlook that all of this happened at the very same time AF447 entered a monstrous thunderstorm. Which contains serious up and downdrafts and consistant warnings for pilots to avoid them.

There is enough evidence to indicate hand flying the A330 at altitude is dicey at best even on a clear day, let alone in turbulence, at night, and with no airspeed indications.

All the other aircraft in the area deviated. Why not this one?

lomapaseo
15th Jul 2011, 21:12
still asking myself: why did they fly into a level 5 CB?

All the other aircraft in the area deviated. Why not this one?


Two posts in a row state as facts about the aircraft flight into a defined thunderstorm without deviation.

I challenge those facts

Where's the investigative data that so states?

To continually speculate for a simple explanation does nothing to furthur the understanding of a complex accident.

SaturnV
15th Jul 2011, 21:27
Henri737 and wallybird7,

There has been a back and forth conversation on this forum about whether they flew into a Cb.

I think perhaps the minimum level of agreement by parties engaged in this conversation is that AF 447, at night with the moon aft, flew into a cloud that had sufficient ice crystals at FL 350 to quickly clog the pitots. There is no consensus on the degree and duration of any turbulence encountered, nor of the existence of updrafts, etc. I believe there is consensus there was no lightning. I don't believe there is agreement on what kind of cloud in the ITCZ might produce ice crystals at FL 350.

Presumably, the next BEA report will soon enlighten us all.

wallybird7
15th Jul 2011, 22:00
SATURNV

No evidence of thunderstorms?????

Please read "Air France Flt 447: A Detailed Meteorological Analysis"
By Tim Vasquez

Every scrap of information on this flight shows a line of thunderstorms directly in line of their flight path.

Every advisory from NASA, to the FAA, advises avoidance by a large margin.

Every professional is aware of thunderstorms and the hazards they pose.

Weather Avoidance Radar is required on every airliner. Why?

MATELO
15th Jul 2011, 23:03
Both main manufacturers and the airlines are leaning more and more towards a situation where the 'systems' hold sway and the pilots are virtually forbidden to fly manually

What chances did these guys have if they were trained to "understand the aircraft will never stall" and they never knew the stall warning would silence itself under 60kts.

Plummeting towards the ocean with no stall warning might lead someone to think they were heading "nosedown" into oblivion, especially in the middle of the ocean at night.

RWA
16th Jul 2011, 04:43
Quoting One Outsider:-

"Then you don't know very far. The 'first duty' of any crew is to fly the aircraft. Any other actions are secondary and are to be performed when not interfering with flying the aircraft."

I didn't say they should or would stop flying the aircraft, One Outsider. That's why there are two of them! But it is the duty of the PNF to read off the ECAM messages, one by one, cancelling each once the PF has absorbed it and then moving on to quote the next.

There's a video here that shows that procedure being carried out. Only a 'sterilised' mockup in the simulator, but it will give you the idea.......

‪Airbus emergency descend after cabin pressure failure‬‏ - YouTube


"Being a mere amateur you are perhaps excused, but with the amount of nonsense already posted there is no need to add more."

I hope (without much hope) that you will now withdraw the word 'nonsense' .........

SaturnV
16th Jul 2011, 05:33
Wallybird7,

I have read Vasquez, both his 2009 and 2011 analyses. I have read the BEA Meteo France analysis in the first BEA report (an appendix in French only). I have read NASA's re-analysis of the Wx. I have noted AF dispatch's message to the crew alerting them that satellite imagery indicated Cb along their route in the vicinity of TASIL.

In the earlier 'conversation' in this forum on whether they flew into a Cb or not, I believe there is agreement that:
> nobody publicly knows what the gain and tilt of their radar was set at, and what they likely saw.
> nobody can yet accurately characterize the nature of the turbulence experienced earlier, other than the cockpit indicating to the cabin crew that the turbulence they were anticipating at 0208-0210 would probably be greater than the previous episode.
> they were using their radar, and made a slight deviation off the track before the pitots iced.
> nobody publicly knows what the CVR transcript may say about any conversation in the cockpit about the weather.
> that the weather in the ITCZ is dynamic, with conditions that can change rapidly.

As I noted earlier, there is agreement that they flew into a cloud with sufficient ice crystals to clog the pitots.

Satellite data has confirmed that areas of very small ice crystals in high concentrations exist within and in the vicinity of large scale convective weather systems. This is especially true in tropical latitudes where these systems are at their most extensive and can produce cloud tops as high as 50,000 feet because sea surface temperatures are at their highest and so more water is absorbed into the developing system. These ice crystals can remain long after the active convection which produced them has begun to decay. They are extremely small - probably only about 40 microns in diameter - and even at high concentrations, are unlikely to be evident visually even by day. With a radar reflectivity of only about 5% of that of average-sized raindrops, they will not appear on airborne weather radar displays either.
.....
The areas of abnormally high crystal concentration are believed to originate from columnar ascent in cumulonimbus cloud and can be expected to drift downwind from the main area of cloud tops. They are an entirely different phenomenon to the more ‘normal‘ occurrence of the ice crystals which give rise to high level Cirrus, Cirrostratus and Cirrocumulus cloud which are at much lower concentrations and do not represent a similar hazard.
SKYbrary - High Level Ice Crystal Icing (http://www.skybrary.aero/index.php/High_Level_Ice_Crystal_Icing)

wallybird7
16th Jul 2011, 07:43
SaturnV

"There has been a back and forth conversation on this forum about whether they flew into a Cb.

I think perhaps the minimum level of agreement by parties engaged in this conversation is that AF 447, at night with the moon aft, flew into a cloud that had sufficient ice crystals at FL 350 to quickly clog the pitots."

A "cloud" that rises to 50,000 is not merely a cloud -- it is a thunderstorm.
It can contain severe up and down drafts and severe turbulence.
The FAA advises avoiding it.
When AF 447 entered this area a multitude of failures occurred.

And yet you are saying it was merely a coincidence. It had nothing to do with all that followed.
I think you need to do some more research on the subject of thunderstorm flying and the hazard it represents.

DL-EDI
16th Jul 2011, 09:16
RWA:

Is the "first duty" nowadays to listen to the systems or is the "first duty" still to fly the aircraft and use the systems as tools to achieve that end? Hasn't the latter been the general philosophy since the first instrument was added to an aircraft? I can't say with any authority.

Henri737
16th Jul 2011, 09:49
SatrunV

Lets not confuse cause and consequences.

what radar system was installed? not seen an answer yet.

SaturnV
16th Jul 2011, 12:37
Henri 737.

The radar system in use was identified much earlier in one of the previous, now-closed threads on this accident. I am not going to search for the posts describing it. It was the same radar system used by AF459, which followed AF447 along the same track by about 35 minutes, but which after ORARO, deviated to the left by about 20 NM and then to the right by 70-80 NM, and did so after adjusting the tilt and gain on the radar.

Wallybird7,

Regarding the 'conversation' earlier in this thread, I do not believe anyone is asserting that the crew deliberately flew into a Cb whose top was subsequently described as being at 520 (Meteo France) or 560 (Vasquez). AF459 began adjusting its radar after unexpected turbulence at 350 in the vicinity of NATAL, in weather described as cumulus congestus. The crew of AF447 may not have been prudent, but I don't believe there is any indication from the CVR excerpts that they were reckless.

As we don't yet have a full CVR transcript, we don't know what, if anything, was said about what they saw on their radar (except for a reference to the anticipated turbulence and a reference to deviating a bit off the track). We don't know if they adjusted the settings on their radar.

As there was no lightning, and the moon was behind them, there was little illumination of the clouds ahead. We do know that a Lufthansa 744 flying 20 minutes ahead at 325 reported it was in the clouds at the time it deviated. The only weather-related comment by the AF 447 crew in the CVR excerpts released by the BEA references the outside air temperature.

No one disputes that the crews of the LH ahead, and the IB and AF459 following, deviated based on what they saw on their radars. The unanswered question is what did AF447 see on its radar that led them to continue on the track, and only attempt a slight deviation when they were in the middle of the 'cloud'.

wallybird7
16th Jul 2011, 21:43
SaturnV
"No one disputes that the crews of the LH ahead, and the IB and AF459 following, deviated based on what they saw on their radars. The unanswered question is what did AF447 see on its radar that led them to continue on the track, and only attempt a slight deviation when they were in the middle of the 'cloud'."

No one knows what they saw or what they understood it to mean.
My concern is why they didn't deviate sooner, and raises the question to me, that there is sort of a cultural issue regarding minimizing the potential hazard a thunderstorm poses. It exists also on this web site whereby the automation and it's "Protections" will save the day.
If a pilot is forbidden to "hand-fly" the plane at altitude in clear weather conditions, and then in a turbulent circumstance is forced to do it, with very limited resources, no airspeed etc, I think it is literally impossible.
This airplane is very fragile having 32 plus adventures with loss of pitot info and subsequent auto failures, and to venture anywhere near major storms is irresponsible.

Turbine D
16th Jul 2011, 21:57
SaturnV,

Here is a post from Thread 2 in the Tech Forum by Graybeard. It notes the onboard radar type. Hope this helps your discussion with wallybird7.


Wx Radar Factor
RR_NDB
Quote:
Ok, let´s look at each point:

1) Crew decided to keep course going through WX.
2) Entered an unexpected WX condition.
...

1) Several possible reasons:
a) Radar in auto mode. The best is to adjust manually the antenna elevation to characterize better the pattern ahead.
b) Shadow from first CB area (as PBS suggested)
1 a) The Wx radar on 447 did not have auto tilt. They had the Collins WXR-700, not the newer WXR-2100.

b) As I explained in detail above, it was not possible for the major line to be shadowed by the intervening cell. In this case, PBS "expert" was a ground radar guy. Rockwell Collins, the maker of 447's radar, was not listed in the credits. If RC didn't want to get involved, they surely could have referred Nova to a knowledgable source.

Here are some possibilities:

1. The storm did not look bad enough to deviate around.
2. The line of storms was so long and uniform, it would not seem to matter where they penetrated.
3. The pilots did not have enough training in Wx radar ops.
. a. Nobody was looking at the radar returns.

SaturnV
16th Jul 2011, 23:43
Thank you Turbine D.

Wallybird7, nearly three weeks ago there was a rather robust discussion in this forum on what they flew into. Rather than my continuing to try to synopsize and synthesize the various views expressed, perhaps the better reply would be to give you links to many of the relevant posts.

http://www.pprune.org/6537291-post1849.html

http://www.pprune.org/6538283-post1865.html

http://www.pprune.org/6538679-post1870.html

http://www.pprune.org/6538743-post1871.html

http://www.pprune.org/6538901-post1875.html

http://www.pprune.org/6538911-post1876.html

http://www.pprune.org/6539033-post1878.html

http://www.pprune.org/6539051-post1880.html

http://www.pprune.org/6539466-post1885.html

http://www.pprune.org/6539692-post1889.html

You may view the failure of the crew in not deviating sooner to be irresponsible, but I think most/all of the earlier posters on the subject of a track through an ITCZ meso-convective system would agree there still is far too little information to form judgments with regard to culpability.

As Vasquez summarized last month,
Tropical storm complexes identical to or stronger than this one [the MCS on June 1] 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.

jcjeant
17th Jul 2011, 01:26
Hi,

Tropical storm complexes identical to or stronger than this one [the MCS on June 1] 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. This is what is called "Russian roulette"
A game can not be a winner ..you always lose .. it's just a matter of time.
To be sure not to lose (or sure to win) should not play "Russian roulette" (do not go in these areas)

TioPablo
17th Jul 2011, 03:17
Next report of BEA is planned to be published end this month... I´m sure we all are planning to do our best! Fly safe!

bubbers44
17th Jul 2011, 03:21
I hope the final report comes out soon from BEA so we don't have to listen to Russian Roulette stories of how they iced up.

lomapaseo
17th Jul 2011, 03:26
Tropical storm complexes identical to or stronger than this one [the MCS on June 1] 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.


This is what is called "Russian roulette"
A game can not be a winner ..you always lose .. it's just a matter of time.
To be sure not to lose (or sure to win) should not play "Russian roulette" (do not go in these areas)

This leads to the same circular argument as volcanic ash. The air we fly through always has some degree of ash, water and turbulence. You can't just say don't fly in them because it's like how high is high.
The pilot can be given guidance but can not be given orders that are black and white without the means to measure. Thus the investigation needs to ask about the guidance and the means as well as the performance of the crew. As far as I know the investigation has not made a conclusion in this regard so why should we?
Weather is dynamic so what another flight did a half hour before or after is only a hint, towards their guidance and means of measurment and not a conclusive finding for the accident flight

RWA
17th Jul 2011, 07:29
Quoting DL-EDI:-

"Is the "first duty" nowadays to listen to the systems or is the "first duty" still to fly the aircraft and use the systems as tools to achieve that end? Hasn't the latter been the general philosophy since the first instrument was added to an aircraft?"

The professionals on here can advise you better, DL-EDI - but my understanding is that in this sort of situation (autopilot/autothrust 'sign off,' 'unreliable speed indications,' etc.) the PF should 'fly pitch and power' (basically keep the pitch attitude at an appropriate level to maintain altitude and (given that one of the few things we can be certain of is that the speed indications had gone haywire) manually apply the correct throttle setting to maintain flying speed). The duty of the PNF, as shown above, is to work through the warnings/messages so as to inform the PF as thoroughly as possible on what has gone wrong. So it's a mixture, with the emphasis on keeping the aircraft at a correct attitude and at a safe speed until (hopefully) the instruments come right (in this case, first and foremost, that the ice in the pitots and ports hopefully melted).

That's the way the AF447 pilots reacted; and it looks as if the PF did in fact manage to keep the aeroplane level and maintain airspeed for some 18 seconds; in other words, 'fly pitch and power' in accordance with the recommended procedure. I've no doubt that, if and when we ever get details of the CVR recording, the two pilots will have been going through the procedure illustrated above - checking each message/warning in turn, trying to find out what had happened/was happening.

What we DON'T know, of course, is what other instruments may have been misbehaving, in addition to the Air Speed Indicators.

Then came the (so far unexplained) zoom-climb, with no evidence of any sidestick input from the PF. Again, the PF appears to have 'done the right thing,' countered the zoom-climb with forward stick and pretty well levelled the aeroplane out again. Further, at some point during this period (the BEA 'neglects' to inform us when this process started and finished) the "Trimmable Horizontal Stabiliser' (what used to be called the 'tailplane' in my day) unaccountably went to 'full up.'

Finally, the stall warning sounded - and once again the PF appears to have 'gone by the book' as it applied at the time, carrying out the recommended procedure at the time - full Take- Off/Go Around power and try to maintain level flight.

At some point during this phase the "Trimmable Horizontal Stabiliser' (what used to be called the 'tailplane' in my day) went to 'full-up'; which would have made it just about impossible to maintain level flight. There have been several accidents due to that happening; Perpignan was one (though pilot error was definitely involved in that accident as well). Another was an MD80, Alaska Airlines Flight 261 - this accident was put down to lack of maintenance, the un-lubricated jackscrew operating the THS first of all jammed with the THS at a 'nosedown' setting, and then broke off altogether. For the record, the Alaska pilots had both to haul their columns back with all their strength just to maintain some sort of level flight, just from the 'down' THS attitude, even before the THS actually broke).

Alaska Airlines Flight 261 - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Alaska_Airlines_Flight_261)

TV dramatisation here too if you fancy watching it - though I warn you, it's long.........

‪Air Crash Investigation - Cutting Corners / Fatal Error - Alaska Airlines Flight 261‬‏ - YouTube

Trouble is, due to what I will politely describe as the BEA's 'reticence' on the contents of the FDR and the CVR, we can form no opinions on what caused the zoom-climb. That brings us to the main difference between modern airliners (particularly Airbus, though Boeing are moving in the same direction); that older aircraft types always left the pilot with the final word; whereas modern 'systems' are designed to overrule them if the systems 'conclude' that the pilots' actions are in some way endangering the airframe or doing other things that (in the opinion of the designers) are dangerous.

Both Boeing and Airbus modified their 'stall avoidance' procedures soon after AF447 went in; the drill now is 'adjust power but don't necessarily use full power, concentrate first on getting the nose down.'

Hope some of that helps.......

Zorin_75
17th Jul 2011, 08:38
That's the way the AF447 pilots reacted; and it looks as if the PF did in fact manage to keep the aeroplane level and maintain airspeed for some 18 seconds;
According to the note more like 11 seconds. Anyway, is that supposed to be a good thing? Orville Wright managed 12 seconds on his first try...

What we DON'T know, of course, is what other instruments may have been misbehaving, in addition to the Air Speed Indicators.

At this point we have nothing indicating that they lost anything other than the airspeed derived data either.

Then came the (so far unexplained) zoom-climb, with no evidence of any sidestick input from the PF.
While I agree that we don't know how strong it was, it's somewhat hard to ignore the "left nose-up input" made just before the climb...

Finally, the stall warning sounded - and once again the PF appears to have 'gone by the book' as it applied at the time, carrying out the recommended procedure at the time - full Take- Off/Go Around power and try to maintain level flight.
Whatever book they were going by, I'd hazard a guess nose-up inputs resulting in 16 deg pitch attitude weren't in it.

At some point during this phase the "Trimmable Horizontal Stabiliser' (what used to be called the 'tailplane' in my day) went to 'full-up'; which would have made it just about impossible to maintain level flight.
It went up because the pilot wanted nose up (that that was probably for a good reason from his perspective is a different story, we will have to wait and see...).

For the record, the Alaska pilots had both to haul their columns back with all their strength just to maintain some sort of level flight, just from the 'down' THS attitude, even before the THS actually broke).
I'm not sure where you see the relevance of that incident, but as you note there the pilots fought with all their strength against the failed THS, which from what we know so far seems not to have been the case at all here...

That brings us to the main difference between modern airliners (particularly Airbus, though Boeing are moving in the same direction); that older aircraft types always left the pilot with the final word; whereas modern 'systems' are designed to overrule them if the systems 'conclude' that the pilots' actions are in some way endangering the airframe or doing other things that (in the opinion of the designers) are dangerous.

So, general anti FBW ranting aside, at which point do you suppose the FCS overrode the pilot's input, causing or contributing to the accident?

DL-EDI
17th Jul 2011, 09:55
That's quite an extensive reply to my simple question, RWA. However, I still don't see that nowadays "listening to the systems" is the crews' "first duty" over flying the aircraft.

So, general anti FBW ranting aside, at which point do you suppose the FCS overrode the pilot's input, causing or contributing to the accident?

As a mere armchair enthusiast, I'm also curious about the answer to this recurring question.

iceman50
17th Jul 2011, 10:54
So, general anti FBW ranting aside, at which point do you suppose the FCS overrode the pilot's input, causing or contributing to the accident? As the A/C was supposedly in Alt Law (ADR Disagree) there would have been NO FCS inputs to cause the pitch up, they are inhibited.

RWA

Both Boeing and Airbus modified their 'stall avoidance' procedures soon after AF447 went in; the drill now is 'adjust power but don't necessarily use full power, concentrate first on getting the nose down.' The manufacturers and regulators re-emphasized the Stall Recovery Procedure not because of AF 447 but because of various other stalls on both Airbus / Boeing and other types. Too much emphasis had been put on minimum height loss with some "instructors"/ schools actually saying use "back" stick to reduce height loss!!!! The UK CAA have just issued a Safety Notice to that effect on the 13th July 2011.

Again, the PF appears to have 'done the right thing,' countered the zoom-climb with forward stick and pretty well levelled the aeroplane out again.BEA reportThe 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.However, if you read the BEA report quoted, the inputs made were then nose up and more than likely caused the THS to move, then when the AOA increased above 30 degrees or the speed dropped below 60 kts - no more autotrim.

At 2 h 10 min 51 , the stall warning was triggered again. The thrust levers were positioned in the TO/GA detent and the PF maintained nose-up inputs. The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight. Around fifteen seconds later, the speed displayed on the ISIS increased sharply towards 185 kt; it was then consistent with the other recorded speed. The PF continued to make nose-up inputs. The airplane’s altitude reached its maximum of about 38,000 ft, its pitch attitude and angle of attack being 16 degrees.The altitude was then about 35,000 ft, the angle of attack exceeded 40 degrees and the vertical speed was about -10,000 ft/min. The airplane’s pitch attitude did not exceed 15 degrees and the engines’ N1’s were close to 100%. The airplane was subject to roll oscillations that sometimes reached 40 degrees. The PF made an input on the sidestick to the left and nose-up stops, which lasted about 30 seconds.

jcjeant
17th Jul 2011, 19:38
Hi,

As we have many technical documentations about the A330 systems and how they are working in the case of the AF447 event .. and pilots actions (thank's to takata and al and BEA interim reports and note) can some ones with same knowledge about the Boeing 777 .. propose a scenario about how will work the B777 systems if confronted at similar event ?

One Outsider
17th Jul 2011, 20:54
RWA,

I do realize that as a professional pilot I have become outnumbered here by instant experts who can tell us 'how it is' by watching youtube videos and quoting wikipedia and what not. I note that you also think you should 'give me the idea' of what I do for a living. Should I say thank you or just laugh?

What slipped past your eagle eye is that the A320 in your video is level in cruise with AP and ATS engaged and under control. It is a video of set piece like a free kick at the edge of the penalty box. It tells you nothing about how to get the ball there in the first place or even how to play at all.

I think I will stick with nonsense, thank you very much.

Poit
19th Jul 2011, 01:53
Hi One Outsider,

As a non-professional pilot, and therefore one of the multitude who now out-number you, there is still one burning question in my mind. I'm not being cheeky towards your post, it's just the most recent one I can reply.

Why the zoom?

I have flown before, in fact I trained in the Aussie Air Force. Ultimately I was unsuccessful on that course because I incorrectly applied good 'airmanship' on several occassions. Those fo-pars that ultimately failed my endeavours were far less serious than failing to apply known procedures to a system failure.

I've said it before, and I'll keep saying it, unless there was some monumental failure of things we haven't heard about yet, the pilots appear ill-trained / equipped to deal with what should be a simple emergency.

before landing check list
19th Jul 2011, 05:05
So, general anti FBW ranting aside, at which point do you suppose the FCS overrode the pilot's input, causing or contributing to the accident?

Is it actually is possible (is it? I really do not know) for the system to have the last word? Be honest please, think, is it possible for the system with A particular set of circumstances to override the pilots? I know it is like asking what if a wing falls off so please humor me with this seemingly naive question. I am just a old DC8/9 guy and the only glass I have flown is on a helicopter.

wallybird7
19th Jul 2011, 05:55
Lomapaseo

All the other aircraft in the area deviated. Why not this one?

Two posts in a row state as facts about the aircraft flight into a defined thunderstorm without deviation.

I challenge those facts

Where's the investigative data that so states?

To continually speculate for a simple explanation does nothing to furthur the understanding of a complex accident.

lomapaseo

Check out " Air France Flt 447: A meteorological analysis "

Not speculation!!

wallybird7
19th Jul 2011, 06:23
BEFORE LANDING CHECK LIST

I'm not fully aware of the A330 specifics -- but it's not so much having the last word, as it is -- doing something the pilots were not aware of.

And my take is with the A/P and A/T clicked off, and in turbulence, without airspeed guidance, and the pilots not allowed to hand-fly an airplane at altitude, and a overly sensitive control system -- it seems to me to be very easy to over control and not be aware of it and also unaware of the side stick inputs they are putting in.

Otherwise why a unusually high pitch attitude? The trim just did what it was told to do.

before landing check list
19th Jul 2011, 08:06
The trim just did what it was told to do.

So... the big question I was leading up to; WHO (Man or machine) told it to do what and why?

Zorin_75
19th Jul 2011, 08:27
before landing checklist,
I think the point is - wouldn't you have been just as dead when applying the same inputs to a DC-8?
If anything, the bus gave them a bigger shovel (autotrim), but it was their decision to start digging. How they'd arrived at that decision seems to be the interesting part.

SaturnV
19th Jul 2011, 10:34
wallybird7, you are suggesting that they deliberately flew into a defined thunderstorm? Defined by who? and when?

From a few pages back in this thread, mm43's corrected image:
http://oi53.tinypic.com/2u7n4vs.jpg

IMO, neither the Lufthansa nor the Iberia flights deviated enough to take them out of the bright green. (I concede I am using a static image to describe a dynamic situation, but the BEA has chosen not to release the precise path of the deviations by those two flights so one can't map against different satellite imagery.) AF459 deviated enough to the right to possibly avoid the bright green.
_______________

Do you have knowledge of the crew of AF447 adjusting the tilt and gain of their radar as AF 459 did, and still proceeding on the track?

Lonewolf_50
19th Jul 2011, 13:30
wally:

wallybird: Two posts in a row state as facts about the aircraft flight into a defined thunderstorm without deviation.
A course deviation of 12 degrees was recorded before this upset event. It's in the BEA report. Was the deviation big enough? Different question.

I'll echo Saturn V's other point: defined thunderstorm conclusion is based upon what criterion? That they knew they were flying into unstable air seems to be confirmed by the brief CVS discussions released to date, and the apparent decision to reduce speed to turbulent air penetration speed before they hit what they expected to be a patch of the rough stuff.

xcitation
19th Jul 2011, 23:07
Pre-flight briefing of AF447 will shed light on whether the storm cluster was expected and to what extent.
Keep in mind that the image above does not use the same color coding as the one we see in on radar. So the AF447 radar could have seen anything from nothing to a wall of red. From what I have read here the use of the gain adjust is critical when traversing the ITCZ.

bubbers44
20th Jul 2011, 00:49
In all my years I have never done a preflight briefing of weather enroute. We look at what is shown and take off knowing what to expect. They must have encountered some icing and their pitot tubes froze up. That alone apparently took the airplane down for some reason. There is no evidence of their deviation 12 miles left of course not being adequate.

Using the fact they crashed is silly. If they iced up 40 miles off course probably wouldn't have made any difference. Hopefully the final report will clarify everything but right now we have zilch info.

bearfoil
20th Jul 2011, 01:57
Assume UAS. Without Airdata, the a/c cannot be autoflown. A new Flight Law is entered, and the PF is the only way to get home (if but temporarily).

Fine. This aircraft has a reputation for being docile, easy fly, and hand flying no problemo. So why no auto flight? Again, no reliable Airdata.

So on the one hand, UAS is not a 'big' deal, but big enough that the a/c cannot do it. Just fly Pitch and Power, one hears.

Fine. Isn't Pitch and Power the easiest (basic) way to fly? So why no auto P/P?

At altitude, in those conditions, PJ2's post describes the hazards of flight re: control damping and authority.

Fine. With turbulence, the a/p has the same airmass to deal with as the Pilots, subject to overcontrol, sensitivity, g and PITCH. So the a/p can do these, but not something so simple as PnP? PnP is what it has been doing since ORARO, with flourishes, and a nice ride?

It is the fundamental duty of autoflight to keep the a/c stable and consistent. What about the challenge of UAS has nothing to do with what an a/p needs to do every day, all day long?

Yet the PF has no access to the accelerometers (except by display), and has to deal with natural conditions that don't affect the a/p one bit?
IE Dark, no constant updata, distraction, and ECAMs?

For once and all, can someone address why it is impossible to consider that the autoflight couldn't (keep up) even with reliable a/s, and UAS may have been the result of insufficient response in the auto regime? (turbulent air mass, discrepant instant baddata?)

someone, splain.

sebaska
20th Jul 2011, 09:52
Assume UAS. Without Airdata, the a/c cannot be autoflown. A new Flight Law is entered, and the PF is the only way to get home (if but temporarily).

Fine. This aircraft has a reputation for being docile, easy fly, and hand flying no problemo. So why no auto flight? Again, no reliable Airdata.

So on the one hand, UAS is not a 'big' deal, but big enough that the a/c cannot do it. Just fly Pitch and Power, one hears.

Fine. Isn't Pitch and Power the easiest (basic) way to fly? So why no auto P/P?

At altitude, in those conditions, PJ2's post describes the hazards of flight re: control damping and authority.

Fine. With turbulence, the a/p has the same airmass to deal with as the Pilots, subject to overcontrol, sensitivity, g and PITCH. So the a/p can do these, but not something so simple as PnP? PnP is what it has been doing since ORARO, with flourishes, and a nice ride?

It is the fundamental duty of autoflight to keep the a/c stable and consistent. What about the challenge of UAS has nothing to do with what an a/p needs to do every day, all day long?

Because, in foreseeble future AP must be kept simple. AP and similar software (it's now software thing) is, compared to many other software systems, quite simple. And if it's going to be certified to fly 400+ pax in crowded skies over densely populated areas it must be kept simple. The key feature of such life critical systems (like AP, FBW controls, dangerous industrial processing controls, like chemical or atomic) is traceability. I.E. each action of the hardware must be clearly traceable to particular instructions in software source code. Then the thing must be proven (often formally, mathematically) that it faightfully represents it's specification.

You want P'n'P of that software, but now how to solve such things like P'n'P while climbing, while descending, while keeping altitude (esp. in reduced vertical separation space), etc. Then if there is UAS AP must be sure it is isolated and is not a sign of some other bigger problem. The human interface would also get more complicated and hard to grasp.


And there is one thing to all that -- the software is deterministic (and in transport planes it will for some significant time into the future). It's meant to always behave the same given the same situation. It has no second thoughts. It has no thoughts at all to begin with. It is preprogrammed for particular behaviours in particular situtations. If situation is not fully understood beforehand the best action is to disconnect the thing. Otherwise it could turn into garbage in - garbage out and you don't want garbage out while moving at Mach 0.8 at FL350.
But there are those two guys (or gals) in front. They're not there to just monitor all that machinery -- with current technology they could better monitor it from some warm place on the ground (as it happens with spacecraft, for example). They're there to handle all the situations which could develop.

Yet the PF has no access to the accelerometers (except by display), and has to deal with natural conditions that don't affect the a/p one bit?
IE Dark, no constant updata, distraction, and ECAMs?
Yes, because those guys and gals are not preprogrammed. AP has no thoughts no understanding. None, nada, nil. All additional conditions like ECAMs etc would add exponentially to complexity of preprogrammed AP.


For once and all, can someone address why it is impossible to consider that the autoflight couldn't (keep up) even with reliable a/s, and UAS may have been the result of insufficient response in the auto regime? (turbulent air mass, discrepant instant baddata?)

UAS could not have been the result of insufficient response. Air which would be 60kts on one side and 180 on the other would simple tear airplane apart. UAS was due to pitot fail not due to turbulence causing reliable but discrepant measurements.

GerardC
20th Jul 2011, 13:09
Originally posted by Bubbers44 : In all my years I have never done a preflight briefing of weather enroute. We look at what is shown and take off knowing what to expect. They must have encountered some icing and their pitot tubes froze up. That alone apparently took the airplane down for some reason. There is no evidence of their deviation 12 miles left of course not being adequate.

Using the fact they crashed is silly. If they iced up 40 miles off course probably wouldn't have made any difference. Hopefully the final report will clarify everything but right now we have zilch info.Congratulations "Bubbers", at last one sensible post on this subject :
1) I can't, either, remember of one pre-flight route modification due to en-route weather ;
2) as far as we know, the cause of the crash is not "flying straight into an active cb" but pitot icing.
Icing conditions can be found anywhere : in, near or far away from convective cells.

bearfoil
20th Jul 2011, 14:50
Thanks. I see your point(s). You have focused on the crux. Obviously, autoflight is well-equipped to fly the a/c. It does so virtually all the time.

How well equipped is the Pilot(s)? The irony is that the auto is sensitive, sophisticated, and connected directly to sensors that are processed instantly, allowing for smooth flight. Hand flying cannot produce the ride in most circumstances that auto can.

Two circumstances:

1. The autoPilot cannot keep up, drops out, and Normal Law remains.

2. Due UAS, the autoPilot drops out, and a/c reverts to Alternate Law.

Both conditions require hand flight immediately ("I have the controls").

It would seem to me that under condition (1), the a/c would revert to Alternate Law, the a/c is having control issues.

It would also seem to me that under condition (2), nothing has changed except an instrument is U/A. An important one, but one that hasn't to do with control, at least initially.

So Condition '1' wants (needs) immediate hands, and condition '2' is recommended "patience", monitor, do nothing, don't maneuver.

Protections would be better retained in condition 2, yes? Especially so since the a/s is not reliable, and ham handedness is more likely?

Protections also for condition 1, since the a/p has indicated control challenges for the PF at handoff?

takata
20th Jul 2011, 16:59
1. The autoPilot cannot keep up, drops out, and Normal Law remains.
This should be rephrased as: if Normal Law remains, auto pilot CAN keep up, there is no reason it drops out (none, zero, zlich, nada, rien, niente, whalou).
Consequently, only your case 2. seems true.
Beside, very good post from Sebaska (above).

funfly
20th Jul 2011, 17:30
As an SEP can I please ask you very experienced pilots a question?
If you are flying an (any) aircraft with no outside vis. and suspect instruments and your body and altimeter gave every indication that you were hurtling downwards at a high ft/sec. would it not be a 'normal' reaction to pull back on the stick irrespective of any flight instrumentation. Could this therefore be a case where old fashioned 'seat of pants' reactions were the wrong ones and less 'flying' training and more 'flight' training might, in this case, have yielded a better outcome.

bearfoil
20th Jul 2011, 18:36
takata noted.

funfly At 10kfpm down, ND creates even more fpm down. Counterintuitive to want to speed up. It also increases the 'g' when one pulls "out" of the ensuing dive (I think 'g' protections won't let him pull out anyway).. PF has surpassed all his flight training when the a/c STALLS. A guessing game for him, and instruments that, even if accurate, would be hard to suss?

infrequentflyer789
20th Jul 2011, 19:05
2. Due UAS, the autoPilot drops out, and a/c reverts to Alternate Law.
[..]

Protections would be better retained in condition 2, yes? Especially so since the a/s is not reliable, and ham handedness is more likely?


Protections or automatics ?

Protections, I'd say definitely not. bad things can (and have) happen when protections kick in on bad data (or on good data with design rules that turn out to be not so good). To engage protections based on known bad data would be poor design.

The protections are a line of defense at the edge of the envelope where you (auto or real pilot) shouldn't be going in normal flight anyway. It shouldn't matter if they aren't there if the plane is flown properly. Yes, that might be more of a problem with UAS + IMC + Turb etc., but it will be a lot more of a problem if the plane starts protecting you based on invalid data. Some UAS events have reported more or less simultaneous stall and overspeed warnings...


On the other hand, having a degraded A/P that held pitch and power (correct for altitude - assuming that's not dud data as well) and probably wings-level might actually be useful in some situations.

Lonewolf_50
20th Jul 2011, 19:10
Bear: g limits are +2.5, so you can assume that 2.5g is the limit for a pull out maneuver.

HN39 posted a modest 1.5 g pull out estimate a few pages back, and offered a conservative altitude loss estimate. (I think he's optomistic ...)

2.5 g is a firm pull out, but you won't typically get a gray out. Consider that 60deg AOB in level flight is a 2 G maneuver, and you may see what the "feel" is in the aircraft under such an acceleration.

2.5 g is within the aircraft's structural limits. It is (per the info I have access to) the limit of flight control accel limits (caveat: if you put on that much G while the airspeed is too slow, you may experience an accelerated stall, which can lead to a violent departure ... but there is no evidence that this is what happened.

Your comment that aircraft won't let you do that appears unfounded. (There was a neat thread elsewhere about CFIT and Proximity to Ground Warnings, and 'save it' manuvers. IIRC we also discussed this in the Air Blue at Islamabad crash thread ...)

As I understand the way the flight control system works, the pilots could pull for, or try to demand demand, more than a 2.5 g, and only get 2. 5 g. If you postulate that the pull out is initiated at altitude (somewhere beween 15-20k I guess, to allow time for the aircraft to react and for acceleration to flying speed and a fudge factor) you'd likely have brown trousers, and a flying aircraft with some margin at the bottom of the pull out as you add power and start getting your aircraft back up to a more comfortable airspeed and altitude.

Or not, and the aircraft impacts the ocean in a different condition than it did.

bearfoil
20th Jul 2011, 19:33
Lonewolf

Many thanks. And also to infrequentflyer789. :ok:

So, PF holds back stick over three minutes. He's mad, or he thinks it's "appropriate"? He's not mad, so does he believe that his a/s and v/s (!) is a descent, (It actually is), and his SS back is going eventually to pull them out of the "Dive"? Of course, the panel (LHS) and ISIS have already told their story to BEA.

"We are going to go through 10". Just a wild guess, but is this comment laden with an opinion that they will recover, and it will be quite low when they do? To me, it means just that, it does not mean "And then we will impact the Ocean." I think he expects the ship to level off. That explains the back stick. This means that logically, there would not be a STALL WRN on the way down. Will we find out if there was?

Before autopilot, and for a time after, there was the "wing leveler". I just think that in any condition, a sharp change to manual flight puts the Pilot in a far deeper hole than an a/p w/o ASI. W/O ASI, an auto pilot can hold altitude (accelerometers), and PITCH (Same). The pilot has no such advantage, with bunk data and PNF holding a book.

BOAC
20th Jul 2011, 20:36
As current contributors will probably know, I am one of the 'old' aviators, but I still find it incredible that these two pilots performed the initial climb. I am less interested in investigation of the 'after the climb' events since I judge these to be incorrect handling for whatever reason, be it training, AB 'philosophy' or just lack of recognition of the stall.

Moving on to Bear's 'pitch/power' AP mode - a good idea, but again you need reams of code with all the pitfalls they bring, to cover all the oddballs that can be thrown. Which attitude to use? How will discrepancies be voted out? Was it IAS or attitude - or something else - that triggered the drop to Bear's system? How will the AP cope if the IAS is actually too close to stall/Mcrit while it flies the correct attitude/power? Will it be capable of recovering from an upset?

No, I still back my call (elsewhere) for properly trained and capable pilots who have the innate ability to sift the wheat from the chaff and an FCS that they can understand and use . In my opinion, 'automation' has still way to go.

mm43
20th Jul 2011, 22:20
Bear

Your Pitch 'n' Power mode is what the AP does all the time for its bread and butter. There are of course a few environmental inputs that it needs to effect this operation in a closed loop manner, e.g. barometric alt, OAT, and CAS amongst others.

How about looking again at a proposed method of replacing the CAS short term when UAS becomes an issue as described in AF447 Thread No.4 page 31 (http://www.pprune.org/tech-log/454653-af-447-thread-no-4-a-31.html#post6547413). The advantage of that proposed method is the AP software operates as per normal and the missing CAS is calculated using all the other parameters that are already known.

This is not meant to be a panacea for all the ills that the PF may be confronted with, e.g. the nose-down right-hand roll. Though in this case if the pseudo CAS was injected seamlessly the AP would have carried on correcting for that perceived external force.

Meanwhile, I'm still contemplating the dynamics of "bubbles" being blown by a grandchild in the bath.:8 :ok:

bearfoil
20th Jul 2011, 23:58
The a/p has its command to provide a particular altitude, airspeed. At the core of this command is PITCH and POWER, yep. I'd be surprised if at disconnect, it lost its recent tracking artifacts. The Pilot is not charged with keeping a three second loop of "last recorded" in his head, as the a/p keeps without a sweat. Frustrating, esteemed Pilots suggest at the beginning to be patient, when all we need is a snapshot of the previous chain of acceptable status points, a normed value and a command, "get us 'here'. A million frames of accelerations? Yes, with random points of data geography such that continued flight can be kept in limits for 5-10 minutes? 5-10 hours? Why not?

wallybird7
21st Jul 2011, 00:17
SaturnV

"wallybird7, you are suggesting that they deliberately flew into a defined thunderstorm? Defined by who? and when?"

What I am saying is that they did not deviate far enough away from the line of thunderstorms.

No one knows for sure the dynamics of any particular thunderstorm except that they can contain severe turulence and up and down drafts and most likely had something to do with loss of pitots and possibly control.

A deviation around the line might add 15 minutes of time and fuel, and if so, my opinion is we wouldn't even be discussing AF447.

wallybird7
21st Jul 2011, 00:35
DO'S AND DON'TS OF THUNDERSTORM FLYING

Above all, remember this: never regard any thunderstorm as “light” even when radar observers report the echoes are of light intensity. Avoiding thunderstorms is the best policy. Following are some Do's and Don'ts of thunderstorm avoidance:

Don't land or take off in the face of an approaching thunderstorm. A sudden wind shift or low level turbulence could cause loss of control.
Don't attempt to fly under a thunderstorm even if you can see through to the other side. Turbulence under the storm could be disastrous.
Don't try to circumnavigate thunderstorms covering 6/10 of an area or more either visually or by airborne radar.
Don't fly without airborne radar into a cloud mass containing scattered embedded thunderstorms. Scattered thunderstorms not embedded usually can be visually circumnavigated.</I>
Do avoid by at least 20 miles any thunderstorm identified as severe or giving an intense radar echo. This is especially true under the anvil of a large cumulonimbus.
Do clear the top of a known or suspected severe thunderstorm by at least 1,000 feet altitude for each 10 knots of wind speed at the cloud top. This would exceed the altitude capability of most aircraft.
Do remember that vivid and frequent lightning indicates a severe thunderstorm.
Do regard as severe any thunderstorm with tops 35,000 feet or higher whether the top is visually sighted or determined by radar.
If you cannot avoid penetrating a thunderstorm, following are some Do's Before entering the storm:

Tighten your safety belt, put on your shoulder harness if you have one, and secure all loose objects.
Plan your course to take you through the storm in a minimum time and hold it.
To avoid the most critical icing, establish a penetration altitude below the freezing level or above the level of —15° C.
Turn on pitot heat and carburetor or jet inlet heat. Icing can be rapid at any altitude and cause almost instantaneous power failure or loss of airspeed indication.
Establish power settings for reduced turbulence penetration airspeed recommended in your aircraft manual. Reduced airspeed lessens the structural stresses on the aircraft.
Turn up cockpit lights to highest intensity to lessen danger of temporary blindness from lightning.
If using automatic pilot, disengage altitude hold mode and speed hold mode. The automatic altitude and speed controls will increase maneuvers of the aircraft thus increasing structural stresses.
If using airborne radar, tilt your antenna up and down occasionally. Tilting it up may detect a hail shaft that will reach a point on your course by the time you do. Tilting it down may detect a growing thunderstorm cell that may reach your altitude.
Following are some Do's and Don'ts During thunderstorm penetration:

Do keep your eyes on your instruments. Looking outside the cockpit can increase danger of temporary blindness from lightning.
Don't change power settings; maintain settings for reduced airspeed.
Do maintain a constant attitude; let the aircraft “ride the waves.” Maneuvers in trying to maintain constant altitude increase stresses on the aircraft.
Don't turn back once you are in the thunderstorm. A straight course through the storm most likely will get you out of the hazards most quickly. In addition, turning maneuvers increase stresses on the aircraft.


Table of Contents (http://www.aviationweather.ws/)
Previous Section: Thunderstorms and Radar (http://www.aviationweather.ws/064_Thunderstorms_and_Radar.php)
Next Section: Common IFR Producers (http://www.aviationweather.ws/066_Common_IFR_Producers.php)

SOURCE: FAA AVIATION WEATHER THUNDERSTORM FLYING

Note: The FAA signs off on my certificate. This is also my Company Policy.

It does not mean failure to comply equals certain death. But it does suggest risk is involved. Paying passengers do not want any risk!

Turbine D
21st Jul 2011, 01:31
wallybird7,

Your post on thunderstorm penetration/avoidance was an interesting read. However, in the ITCZ, very nearly all the storms are not thunderstorms. The storms are tropical storms that do not contain lightning and therefore, no thunder. At night visually, with no light from the moon, one would not know they were there. The clue to their presence would be the radar and how it maybe being monitored and used.

It would be my guess and it is strictly a guess, they were late in using their radar to interpret what lay ahead. But with some other clues, they began to, "Can you move a little to the left?" If the static satellite overlay in a couple of previous posts is correct and I think it is as close as we will see, they did recognize the CB buildups (rather late) and were trying to shoot the gap between two. IMHO, what then caused the problem was the pitot situation leading to AP/AT disconnect.

As I recall the LH track before it was taken down, LH did not completely go around either, but shot a gap between two CB buildups a little further to the West. They did however, start their turn Westward earlier.

Just some thoughts.

bubbers44
21st Jul 2011, 03:14
The 12 degree deviation left in their opinion was adequate for the weather they were penetrating. If they had deviated either direction 30 degrees the outcome would have been the same. When their pitot tubes froze up they lost control of the airplane. They didn't have the ability to fly that airplane with UAS with their experience. Soon the final report will come out and we can confirm that but right now speculation of what happened is all we have. The pitching over 15 degrees up with a loss of airspeed indication says a lot.
So far that is all we know they lost. Maybe a few bumps.

RWA
21st Jul 2011, 05:49
"Why the zoom?"

I agree that that's a key question, poit. The BEA's report is pre-occupied with 'noseup inputs' on the part of the PF, but even the report credits the PF with a correct response to the 'zoom':-



"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."


That was the first phase of the upset. The next phase started with the stall warning sounding. The PF appears to have responded with the correct drill at the time - 'TO/GA power and seek to maintain altitude':-



"At 2 h 10 min 51, the stall warning was triggered again. The thrust levers were positioned in the TO/GA detent and the PF maintained nose-up inputs. The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight."

This was the crucial 'second phase.' Whether this was the result of TO/GA power pushing the nose up, the PF's inputs, the THS going to 'full up,' or the thin air at 38,000 feet, or whatever, we don't know; my own feeling is that it was probably the result of a combination of all those factors. In any event, the aeroplane appears to have 'sat on its tail' and entered a deep stall.

We don't know what instruments the pilots had available at that time. However, I suspect that they were at first pre-occupied with the rapid loss of altitude, and formed the view that the aeroplane was in a dive rather than a stall. After all, the stall warning had stopped, that may have given them the impression that they had successfully 'avoided' any stall. It annoys me that the BEA probably KNOWS, from the CVR, what the pilots reckoned 3was goingon (unless they descended over 20,000 feet without saying anything at all to each other?).

There was in fact a third phase. In that connection I next have to mention a 'leak' published early on by 'Der Spiegel'; not the most reliable source, obviously, but it has never been denied:-

"The BEA report, in its current form, only provides the angle of the stabilizer but provides no explanation as to why. The report merely indicates that it was at this moment that Captain Marc Dubois re-entered the cockpit.

"Exactly what orders he issued are not part of last Friday’s report. But sources close to the investigation are saying that he said: “This is a stall. Reduce power and nose down!”

Spiegel: Questions Raised about Airbus Automated Control System | Airlineberg.com (http://www.airlineberg.com/index.php/2011/05/30/spiegel-questions-raised-about-airbus-automated-control-system/)

Indeed, a changed (and more correct) approach is indeed referred to in the BEA report, while the aeroplane still had over 10,000 feet in hand:-

"At 2 h 12 min 02, the PF said "I don’t have any more indications", and the PNF said "we have no valid indications". At that moment, the thrust levers were in the IDLE detent and the engines’ N1’s were at 55%. Around fifteen seconds later, the PF made pitch-down inputs. In the following moments, the angle of attack decreased, the speeds became valid again and the stall warning sounded again."
However, as we all know, the aeroplane never recovered from the deep stall. In this connection I have to quote the BEA again; saying that, even though the PF duly (even if belatedly) applied 'nosedown inputs,' "the THS remained in the latter position until the end of the flight." That is, remained at 13 degrees up.....

I'm afraid that that opens up the possibility that the THS didn't just go to 13 degrees up; but that, like the THS on that Alaskan Airlines MD80, it then jammed there?

iceman50
21st Jul 2011, 06:37
RWA

Give up would you. You just keep spouting the same old rubbish which has been pointed out to you many times.:ugh::ugh::ugh:

The PF appears to have responded with the correct drill at the time - 'TO/GA power and seek to maintain altitude':- That is complete rubbish stall recovery is NEVER maintain altitude!!!!! and the low speed recovery was NEVER maintain altitude either!!!!

Read the BEA report and try to understand it the THS went to the nose up position because the PF demanded it! It then stayed there because autotrim was then disabled and all they had to do was use the trim wheel to reset the THS and it would have been annunciated on the PFD.:rolleyes::rolleyes:

Zorin_75
21st Jul 2011, 11:04
It then stayed there because autotrim was then disabled
From my understanding they never left alternate law so autotrim was active all the way?

RWA
21st Jul 2011, 11:07
Quoting iceman50:-


That is complete rubbish stall recovery is NEVER maintain altitude!!!!! and the low speed recovery was NEVER maintain altitude either!!!!

So this and other articles about 'revised procedures' since AF447 and other incidents are all just wrong?


"Investigators have been left attempting to explain why the crew of Air France (http://www.flightglobal.com/landingpage/air%20france.html) flight AF447 failed to recover the Airbus A330 (http://www.flightglobal.com/landingpage/airbus%20a330.html) from a high-altitude stall, a predicament which has been the subject of a recent revision of safety procedures.

"The revision concentrates on placing greater emphasis on reducing excessive angle of attack - the critical characteristic of a stall - rather than the classical approach of training pilots to power their way out of a near-stall with minimum loss of altitude.

----------------

"The revised recovery procedure was agreed between the major airframers, including Airbus (http://www.flightglobal.com/landingpage/airbus.html) and Boeing (http://www.flightglobal.com/landingpage/boeing.html), some 12 months after the loss of AF447, although a source familiar with the investigation stresses that the change was "not prompted" by the accident.

"At the heart of the revision is an acceptance that classical high-power recovery is not appropriate for every stall condition.

"Simply applying maximum thrust could be ineffective in reducing the angle of attack and averting a stall, particularly at cruise altitudes where the available thrust would be limited and the engines would require time to spool up.

"There is also a risk that the crew might fail to recognise that the aircraft has crossed the threshold from a near-stall into an actual stall, and continue to apply a recovery technique which is no longer effective.

The new procedure is designed to cover all stall conditions. It recognises that recovering the angle of attack might instead require a reduction of thrust, to regain pitch-down authority, as well as a loss of altitude."

http://www.flightglobal.com/articles/2011/05/28/357321/revised-stall-procedures-centre-on-angle-of-attack-not.html (http://www.flightglobal.com/articles/2011/05/28/357321/revised-stall-procedures-centre-on-angle-of-attack-not.html)

I guess we were all taught 'stall recovery' when we first learned to fly. In daylight, at a reasonable altitude, with plenty of warning, a visible horizon, etc.? And that the very first thing we were told to do was to get the nose down? But I guess that it simply isn't possible to let trainee airline pilots stall an actual transport category aircraft - so it all has to be done on simulators only.

My impression is that such pilots are in fact taught only 'stall avoidance,' not actual 'stall recovery.' And that it is therefore entirely possible that the unfortunate AF447 pilot heard the stall warning and carried out the 'avoidance' procedure prescribed at the time. But that, further - given that the stall warnings stopped (even though that was, in all probability, only because the airspeed had dropped almost to nothing) - the pilot assumed for quite a while that his 'avoidance manouevre' had been successful?

BOAC
21st Jul 2011, 11:07
wallybird - I would ask you to carefully read both the current and old threads on this topic? Your fixation on 'thunderstorms' is out of place based on what we are told by BEA. There is also no firm 'evidence' of any 'thunderstorms' on their route.

There is no evidence that they 'penetrated' or flew near a 'thunderstorm'.

It is shown (in the reports) that their 'choice' to deviate to the west proved to be a better one than other aircraft which went to the east.

We do need more from BEA (hopefully 'at the end of the month') to tell us what radio calls and conversations actually took place on the flight deck. We just do not know enough at the moment.

bubbers44
21st Jul 2011, 11:18
stall recovery in the 60's lower nose and max power
same for 70's 80's until the 90's.
Then you had to use max power and not lose more than 50 ft for some reason. Secondary stalls became a problem then. Guess things haven't changed much since the 90's.

sebaska
21st Jul 2011, 13:46
@RWA:
The next phase started with the stall warning sounding. The PF appears to have responded with the correct drill at the time - 'TO/GA power and seek to maintain altitude


Nope. The drill for UAS was TOGA and 5deg nose up. At that moment (as per BEA) the plane was already 6deg nose up. So making persistent (for over minute as per BEA) nose up inputs to get attitide from (initial) 6 deg up down to 5 deg up is not certainly proper drill. The craft was still climbing (at 700fpm from 37500 to 38000) so maintain altidude does not seem yet to be an issue (or it'd rather dictate nose down).

The reason for nose up inputs (inputs, not surfaces position, but pilot inputs at the stick) remains unxeplained as for now.


This was the crucial 'second phase.' Whether this was the result of TO/GA power pushing the nose up, the PF's inputs, the THS going to 'full up,' or the thin air at 38,000 feet, or whatever, we don't know; my own feeling is that it was probably the result of a combination of all those factors. In any event, the aeroplane appears to have 'sat on its tail' and entered a deep stall.

Coffin corner has been calculated for that plane by one of the experienced posters here. It was determined to be 46000ft. Even if the air was somewhat warmer (as crew discussions as disclosed by BEA indicate) it was rather no worse than 43000ft -- still 5000ft above 38000ft achieved by the plane. And the fact is that the plane was slowed down to Mach 0.68 before stall warning came -- so there was a margin from 0.68 to somewhere around 0.85 -- hardly a corner.

iceman50:
Read the BEA report and try to understand it the THS went to the nose up position because the PF demanded it!


Exactly. It's stated explicitly. All the discussion about the reasons of trim going fully nose up is inventing (non)facts to fit someone's pet theories.

It then stayed there because autotrim was then disabled and all they had to do was use the trim wheel to reset the THS and it would have been annunciated on the PFD.:rolleyes::rolleyes:

It seems more probable that there was no mode change to Abnormal attitude. Most probably because IAS below 60kts caused AoA readings to be treated as unreliable and thus disregarded by mode change logic. At the same time to get that (auto)trim down by the use of stick it'd require consistent nose down inputs lasting for time long enough to equalize previous nose up action. "Nose-neutral" inputs won't change (auto)trim, as someone few tens of pages back noticed.

BTW. Wrt AoA relaibility at slow speeds. There was recently thread about rejected takeoff above V1 incidedent and investigation body's take on in. One interesting tidbit pertaining to our discussion is AoA plot from FDR from that plane as presented in the report. As speed of the plane decreased below ~45-50kts measured AoA started to deviate and at ~40kts in went completely wild (like 60 or even 90deg). That plane was on the ground so it's real AoA remained allmost constant.

iceman50
21st Jul 2011, 13:47
RWA

The problem is you keep misinterpreting the information. Maintaining ALTITUDE was NEVER required.

Zorin_75

If you read the report the AOA increased beyond the threshold for Abnormal Attitude Law to come into force, so Autotrim would not be available.

BOAC
21st Jul 2011, 13:53
BEA said abnormal law did not trigger.

See 'Flight Global (http://www.flightglobal.com/articles/2011/06/01/357394/stalled-af447-did-not-switch-to-abnormal-attitude-law.html)'

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.

Lonewolf_50
21st Jul 2011, 14:21
@funfly:

As an SEP can I please ask you very experienced pilots a question?
If you are flying an (any) aircraft with no outside vis. and suspect instruments and your body and altimeter gave every indication that you were hurtling downwards at a high ft/sec. would it not be a 'normal' reaction to pull back on the stick irrespective of any flight instrumentation. Could this therefore be a case where old fashioned 'seat of pants' reactions were the wrong ones and less 'flying' training and more 'flight' training might, in this case, have yielded a better outcome.

What do you mean by "suspect instruments" in this case?

The primary scan instrument is your attitude indicator/artificial horizon. Unless the BEA find something new in their analysis, we are absent evidence of a failed attitude indication.

If I am flying IFR and my artificial horizon has tumbled or failed, I then have to use a partial panel scan (are my turn and slip working? Is my VSI working? Is my altimeter working?) If no to those questions, I am screwed mightily.

But if they are, I work my butt off via my partial panel scan to cross check to get back to straight and level. Recall: the A330 has three laser ring gyros, also called Inertial Reference Units. These feed the attitude indicators. (there is also a back up gyro on the ISIS display cluster).

All else considered, one thing I have to fight like hell is to overcome any feeling of seat of the pants, since in IMC it can give me the leans and kill me via the classic death spiral. (See JFK Junior for a tragic example of that ...)

To say it again, with feeling: if I am flying without visual reference to the horizon (on instruments), then seat of the pants sensations can fool me.

I have to, I must, use a disciplined instrument scan to ensure safe flying.

I am pretty sure that you will hear the same from every CFII you ever meet. I'd be stunned if you don't.

Graybeard
21st Jul 2011, 14:34
SEB: . . Wrt AoA relaibility at slow speeds. There was recently thread about rejected takeoff above V1 incidedent and investigation body's take on in. One interesting tidbit pertaining to our discussion is AoA plot from FDR from that plane as presented in the report. As speed of the plane decreased below ~45-50kts measured AoA started to deviate and at ~40kts in went completely wild (like 60 or even 90deg). That plane was on the ground so it's real AoA remained allmost constant.447 could not have very low speed for very long. It was either moving forward, or dropping fast enough to keep the AOA vanes pointed into the relative wind.

It still puzzles me why the 330 uses airspeed input to the stall warning. McDouglas airplanes don't.

RWA
21st Jul 2011, 16:20
Quoting sebaska quoting iceman50:


"Read the BEA report and try to understand it the THS went to the nose up position because the PF demanded it!"

Exactly. It's stated explicitly.



Please - either of you - please provide a reference to the part of the BEA report you're referring to? I've read it thoroughly, several times, and if it says anything like that I must have missed it?

aguadalte
21st Jul 2011, 16:54
BOAC:
No, I still back my call (elsewhere) for properly trained and capable pilots who have the innate ability to sift the wheat from the chaff and an FCS that they can understand and use . In my opinion, 'automation' has still way to go.

BOAC, I'm with you 100%. I still think that the best way to avoid accidents is to have properly trained and capable pilots in the cockpit flying an ("honest") aircraft easy to understand and very straightforward to handle. Maybe you're right to have a feminine word for airplane... Like women, they seem to have their days...http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/yeees.gif (in our lexicon we have a male word for airplane).

xcitation
21st Jul 2011, 17:03
@RWA

THS overview...

Pitch control is through 2 independent elevators and a trimmable hydraulic stabiliser (THS). These surfaces are normally driven by PRIM 1 by the green hydraulic jacks and THS motor 1. If all 3 PRIMs are lost, electrical control of the THS is lost; actuation is available through the manual pitch trim wheel control. 2 electrically controlled hydraulic servo jacks are fitted to each elevator having 3 modes: active in which the jack is positioned is electrically controlled, damping where the jack follows surface movement and centring where the jack is hydraulically maintained neutral. In normal operation, one jack is active, one is damping. If both servo-jacks fail, they default to the centring mode. Some manoeuvres cause the second jack to become active. The stabiliser is actuated by a screw jack driven by 2 hydraulic motors controlled by 1 of 3 electric motors or the mechanical trim wheel. The right elevator uses GRN & YLO hyd, left uses BLU & GRN. The THS uses BLU & YLO.

If a failure occurs in PRIM 1, assoc hyd system or hyd jacks, control is transferred to PRIM 2 for the elevator via the BLU and YLO jacks and the THS via motor 2. If both PRIM 1 & 2 are inop, control is transferred to SEC 1 for the elevator and PRIM 3, motor 3 for the THS. If all 3 PRIMs are inop, the elevator is controlled by SEC 1 and electrical control of the THS is lost.


See below BEA report quotes with my own bold and underscore for emphasis.

It has been stated by posters that in ALT LAW under some conditions the auto trim feature on THS can be inhibited and pilot should utilize manual trim as required.


At 2 h 10 min 51 , the stall warning was triggered again. The thrust levers were positioned
in the TO/GA detent and the PF maintained nose-up inputs. The recorded angle of attack, of
around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable
horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and
remained in the latter position until the end of the flight.





After the autopilot disengagement:

the airplane climbed to 38,000 ft,
the stall warning was triggered and the airplane stalled,
the inputs made by the PF were mainly nose-up,
the descent lasted 3 min 30, during which the airplane remained stalled. The angle of
attack increased and remained above 35 degrees,
the engines were operating and always responded to crew commands.

iceman50
21st Jul 2011, 17:15
BOAC

Perhaps they missed this


ABNORMAL ATTITUDE LAWS

An abnormal attitude law in pitch and roll is provided if the aircraft is in flight and in any of these conditions :
— Pitch attitude > 50 nose up or 30 nose down
— Bank angle > 125 
— Angle of attack>30or<10
— Speed>440ktor<60kt
— Mach>0.96or<0.1
The law in pitch is the alternate law without protection (except load factor protection) and without auto trim. In roll it is a full authority direct law with yaw alternate.
After recovery, the flight controls laws are:
in pitch : alternate law
in roll : direct law with yaw alternate law

RWA
21st Jul 2011, 17:23
I see what you're getting at, xcitation. But the BEA report goes on to say:-

"At 2 h 12 min 02, the PF said "I don’t have any more indications", and the PNF said "we have no valid indications". At that moment, the thrust levers were in the IDLE detent and the engines’ N1’s were at 55%. Around fifteen seconds later, the PF made pitch-down inputs. In the following moments, the angle of attack decreased, the speeds became valid again and the stall warning sounded again."


So if the THS responded to the 'nose-up inputs,' why did it not also respond to the nose-down ones, and instead remain at full nose-up?

While the aeroplane (and the pilots) still had more than 10,000 feet of altitude in hand? Allowing plenty of time for the pilots to level out, climb back to height, and continue on their way?

armchairpilot94116
21st Jul 2011, 18:00
Any chance the stabilizer jammed or otherwise stayed in full up position (by design) like Ci Nagoya crash?

Accident Database: Accident Synopsis 04261994 (http://www.airdisaster.com/cgi-bin/view_details.cgi?date=04261994&reg=B-1816&airline=China+Airlines)





excerpts from Ladkins report on the Ci TAipei Crash pertaining to the Ci Nagoya crash (both crashes the same type of aircraft)

The Crash of Flight CI676, a China Airlines Airbus A300, Taipei, Taiwan, Monday 16 February, 1998: What We Know So Far (http://www.rvs.uni-bielefeld.de/publications/Incidents/DOCS/Research/Rvs/Misc/Additional/Reports/taipei/taipei.html)


"[02.19]

On 26 April 1994, an Airbus A300-600 crashed tail-first while trying to land at the airport in Nagoya, Japan. The co-pilot, who was flying, had inadvertently triggered the Take-off/Go-around (TOGA) switch on the engine power levers. This caused the Flight Director (an advisory device on the Attitude Indicator) to switch to GO-AROUND mode, and increased thrust on the engines. The autopilots were subsequently engaged, with GO-AROUND mode still engaged. The co-pilot applied heavy nose-down forces to the control column under the Captain's instructions, and continued to do so. The autopilot on this A300 did not disengage under these forces, specifically because of its design. Thus it attempted to counteract the nose-down attitude of the aircraft by putting in nose-up trim on the Horizontal Stabiliser (the moveable, horizontal part of the tailplane, the empennage), causing an abnormal out-of-trim situation. The copilot and the autopilot were thus fighting each other. The captain took over control, judged that landing would be difficult, and opted for a go-around. The abnormal nose-up trim caused the aircraft to pitch up drastically, losing airspeed very quickly, stall, and impact the ground tail-first. The final report from the Japanese authorities singled out 12 causal factors. I quote in full from the report. My comments are in parentheses with the form "[..... PBL]"

While the aircraft was making an ILS approach to Runway 34 of Nagoya Airport, under manual control by the F/O [First Officer PBL], the F/O inadvertently activated the GO [GO-AROUND PBL] lever [positioned on the thrust levers PBL], which changed the FD (Flight Director) to GO AROUND mode and caused a thrust increase. This made the aircraft deviate above its normal glide path.

The APs [Autopilots PBL] were subsequently engaged, with GO AROUND mode still engaged. Under these conditions the F/O continued pushing the control wheel in accordance with the CAP's [Captain's PBL] instructions. As a result of this, the THS (Horizontal Stabilizer) [the horizontal part of the tailplane, the empennage PBL] moved to its full nose-up position and caused an abnormal out-of-trim situation.

The crew continued approach, unaware of the abnormal situation. The AOA increased, the Alpha Floor function [a particular automatic control function intended for situations in which a high angle-of-attack (AOA), the incidence of the wings to the air, is very high. A high AOA leads to a stall PBL] was activated and the pitch angle increased.
It is considered that, at this time, the CAP (who had now taken the controls), judged that landing would be difficult and opted for go-around. The aircraft began to climb steeply with a high pitch angle attitude. The CAP and the F/O did not carry out an effective recovery operation, and the aircraft stalled and crashed.

The AAIC [Japanese Air Accident Investigation Commission PBL] determined that the following factors, as a chain or a combination thereof, caused the accident:

The F/O inadvertently triggered the Go lever It is considered that the design of the GO lever contributed to it: normal operation of the thrust lever allows the possibility of an inadvertent triggering of the GO lever.
The crew engaged the APs while GO AROUND mode was still engaged, and continued approach.
The F/O continued pushing the control wheel in accordance with the CAP's instructions, despite its strong resistive force, in order to continue the approach.
The movement of the THS conflicted with that of the elevators, causing an abnormal out-of-trim situation.
There was no warning and recognition function to alert the crew directly and actively to the onset of the abnormal out-of-trim condition.
The CAP and F/O did not sufficiently understand the FD mode change and the AP override function. It is considered that unclear descriptions of the AFS (Automatic Flight System) in the FCOM (Flight Crew Operating Manual) prepared by the aircraft manufacturer contributed to this.
The CAP's judgment of the flight situation while continuing approach was inadequate, control take-over was delayed, and appropriate actions were not taken.
The Alpha-Floor function was activated; this was incompatible with the abnormal out-of-trim situation, and generated a large pitch-up moment. This narrowed the range of selection for recovery operations and reduced the time allowance for such operations.
The CAP's and F/O's awareness of the flight conditions, after the PlC took over the controls and during their recovery operation, was inadequate respectively.
Crew coordination between the CAP and the F/O was inadequate.
The modification prescribed in Service Bulletin SB A300-22-6021 had not been incorporated into the aircraft.
The aircraft manufacturer did not categorise the SB A300-22-6021 as "Mandatory", which would have given it the highest priority. The airworthiness authority of the nation of design and manufacture did not issue promptly an airworthiness directive pertaining to implementation of the above SB.
It should be fairly clear that most of these causal factors pertain to the crew's actions and understanding of the aircraft systems. However, contributing were unclear manual descriptions (also a factor in the Lufthansa Warsaw A320 crash in 1993 and the Birgenair Puerto Plata B757 crash in 1996), and the placement and design of the GO-AROUND lever on the thrust levers. Also that China Airlines had not performed a recommended modification to the aircraft.

The modification has to do with pilot inputs to the con......."

Remote but was there any failure between man and machine that locked the rear stabilizer in full up by any chance on AF 447 ?

wallybird7
21st Jul 2011, 18:25
BOAC

"wallybird - I would ask you to carefully read both the current and old threads on this topic? Your fixation on 'thunderstorms' is out of place based on what we are told by BEA. There is also no firm 'evidence' of any 'thunderstorms' on their route.

There is no evidence that they 'penetrated' or flew near a 'thunderstorm'."

BOAC

Forget the threads. Read AF447: A Meteorological Analysis.

EVERY professional pilot KNOWS that a line of thunderstorms lay in the flight path of this flight. And every one I know stated "Why didn't they deviate?"

Some may be benign. Others may not.

wallybird7
21st Jul 2011, 18:30
Turbine D

"Nearly all are not thunderstorms..."

Unfortunately, some are! And this one proved deadly.

bearfoil
21st Jul 2011, 18:38
armchairpilot94116

Having taken shelter under my nomex umbrella, I would like to say how delightful it would be to discuss the mechanical architecture of the THS (and elevators). Without prejudice, a discussion of the power supplies, articulation geometry and other would be a fantastic foundation for understanding the ultimate upshot of the explanation for the lack of ND re: THS on the way down. For the moment, PE is the working theory.

Fine, no bad. Lacking airstream damping consistent with cruise speed, did the jack overspeed? Did it, not encountering a back lash from the THS, shift thrust faces on its screw and lock? For the partisans: No offense, none intended, and save your energy for later, eh?

Turbine D
21st Jul 2011, 18:56
It was not a thunderstorm it was a convective system, there was not any reported lightning by a satellite and sensors that monitors the presence of lightning. Read the first BEA report, again. Read Tim Vasquez's update, again.

Hint: From Tim: * Lightning -- Though in earlier versions of this study I had identified lightning as occurring in this mesoscale convective system, recent evidence from spaceborne and sferic sensors indicate that this system contained little or no lightning. Soundings do indicate moderate levels of instability, but there are indications in the literature that cumulonimbus clouds in oceanic equatorial regions entrain considerable quantities of drier, cooler air that dampen upward vertical motion in the lower portions of the storm, and in some way this reduces charge separation 2. In any case it does look fairly likely that we can rule out a lightning strike as being a factor in the A330 crash. That said, it should be emphasized that lightning is modulated by distribution of ice and water fields within a cloud and is influenced by updraft strength, and is not simply a function of the storm's severity or predisposition for turbulence. Whether the aircraft was struck is the main item of concern, and it appears no such event occurred.

Lonewolf_50
21st Jul 2011, 19:11
Curious: How much of the tail (THS and elevators and all that is connected to them) section was recovered from the underwater grave?

May need to go back a thread or two and check out the various photographs.

bearfoil
21st Jul 2011, 19:19
Just as some CVR may be upsetting to the families, likewise some pics of the empennage may be upsetting to Airbus?

I found nothing, save Machaca's excellent pic of the 330 innards complete with jackscrew and RCU.........

There was that "Unidentified" pile of debris to the Northeast in the debris field, I always took that to be the tail feathers. No comment from BEA re: (that I can recall).

MLA. Interesting. Wasn't a spoiler located and recovered in the initial search? Wasn't it one of "4,5,6?" Could the 'g' have been =>2 on the climb? Could a spoiler anomaly have been the result of overstress at initial NURL? Thus far, ACARS is unable and BEA unmoved, to address mechanicals? ~500knots and a manual input initiating an extreme ascent?

Food for thought?

Lonewolf_50
21st Jul 2011, 19:44
Bear, on your behalf, I will slightly misquote a CINCPACFLT signal, circa 1944 ...Where is the reason for the loss of the spoiler? The world wonders.

bearfoil
21st Jul 2011, 19:50
Just to add that I believe the sensor for Spoiler deflection is mounted on the actuator, not on the control surface. lonewolf?

mm43
21st Jul 2011, 20:02
iceman50ABNORMAL ATTITUDE LAWS

An abnormal attitude law in pitch and roll is provided if the aircraft is in flight and in any of these conditions :
— Pitch attitude > 50° nose up or 30° nose down
— Bank angle > 125°
— Angle of attack > 30° or < 10°
— Speed > 440kt or < 60kt
— Mach > 0.96 or < 0.1
The law in pitch is the alternate law without protection (except load factor protection) and without auto trim. In roll it is a full authority direct law with yaw alternate.
After recovery, the flight controls laws are:
in pitch : alternate law
in roll : direct law with yaw alternate law The conditions described above, due to the "any" in the first sentence, are assumed to be "mutually exclusive" and any one or a combination will trigger ABNORMAL ATTITUDE LAW.

Not so, and the FCOM has unintentionally lead everyone astray.

Due to the discrepancy in the airspeed measurement, all three ADRs were rejected by the FCC, which left either of the inertial input criteria:-

— Pitch attitude > 50° nose up or 30° nose down
— Bank angle > 125°

to be met. This didn't happen.

xcitation
21st Jul 2011, 20:16
@RWA

So if the THS responded to the 'nose-up inputs,' why did it not also respond to the nose-down ones, and instead remain at full nose-up?


Good question.
To be specific I think your question is how do we reconcile this contradiction in BEA report:

At 2 h 10 min 51
...13 degrees nose-up in about 1 minute and
remained in the latter position until the end of the flight.

and then

At 2 h 12 min 02
...PF made pitch-down inputs. In the following moments, the angle of attack decreased, the speeds became valid again and the stall warning sounded again.

IMHO the BEA are making a generalization saying THS stayed at +13 deg, or else how do we explain the pitch down inputs followed by a change in AoA. In which case this appears to be rather sloppy writing or a poor translation from the french original. What they should have said "...remained [mostly] in the latter position...".

jcjeant
21st Jul 2011, 20:26
Hi,

At 2 h 10 min 51
...13 degrees nose-up in about 1 minute and
remained in the latter position until the end of the flight. IMHO the BEA are making a generalization saying THS stayed at +13 deg, or else how do we explain the pitch down inputs followed by a change in AoA. In which case this appears to be rather sloppy writing or a poor translation from the french original. What they should have said "...remained [mostly] in the latter position...". The french note tell EXACTLY the same

Le plan horizontal réglable (PHR) passe de 3 à
13 degrés à cabrer en 1 minute environ ; il restera dans cette dernière position jusqu'à
la fin du vol.It's a very affirmative statement from BEA and let no gap for interpretation.
So it stay on 13° to the end despite some elevators command to dive
Some justified this because the elevators commands to dive are too short .........
This must certainly be show better on the FDR than on the CVR :)

bearfoil
21st Jul 2011, 20:35
And yet, when describing Pilot input, they use a squishy "..mainly NU inputs...."

sauce for the goose? Commercial hypocrisy?

Or, were the PF inputs limited to independent elevators only (to include Roll?) Because the THS couldn't/wouldn't "move"?

funfly
21st Jul 2011, 22:09
Thanks Lonewolf 50, thanks for a sensible reply to my question, I realise I am getting a bit off subject.
"I have to fight like hell is to overcome any feeling of seat of the pants, since in IMC it can give me the leans and kill me via the classic death spiral"
I personally have flown in non visibility situations both without and with instrument training (the former nearly killing myself!) thus I appreciate how 'seat of the pants' flying does more harm than good in certain situations. Questions are often posed about the lack of basic 'flying' training of commercial pilots and it may be argued that in some situations a 'boffin' might do better than a 'flyer'?

wallybird7
22nd Jul 2011, 00:45
Turbine D

"Whether the aircraft was struck is the main item of concern, and it appears no such event occurred."

All that refers to is the fact that the plane was probably not struck by lightning.

It still confirms the fact that strong updrafts were probable as well as turbulence and that alone was enough to cause the pilots to lose control of the airplane. Which they did.

bubbers44
22nd Jul 2011, 01:28
w7, you seem a bit warped.

iceman50
22nd Jul 2011, 02:28
mm43

Not so, and the FCOM has unintentionally lead everyone astray.

Due to the discrepancy in the airspeed measurement, all three ADRs were rejected by the FCC, which left either of the inertial input criteria:-

It does not say that in the BEA report, it is a "rumour".

The AOA values were being used by the A/C otherwise the Stall warnings would not have occurred. So the A/C would have sensed that it was at an AOA of greater than 30 and autotrim would have then been inhibited.

"We" cannot make any further "arguments" or state "causes" on this thread until the "FULL" BEA report is published.

mm43
22nd Jul 2011, 03:08
iceman50It does not say that in the BEA report, it is a "rumour".In the meantime I'll live with the "rumour", and I'm certainly not going to die for it.:}

Machinbird
22nd Jul 2011, 04:34
The conditions described above, due to the "any" in the first sentence, are assumed to be "mutually exclusive" and any one or a combination will trigger ABNORMAL ATTITUDE LAW.

Not so, and the FCOM has unintentionally lead everyone astray.

Due to the discrepancy in the airspeed measurement, all three ADRs were rejected by the FCC, which left either of the inertial input criteria:-

— Pitch attitude > 50° nose up or 30° nose down
— Bank angle > 125°

to be met. This didn't happen. Now imagine you are pushing the nose down to recover the aircraft from the stall, and airspeeds becomes valid, and you get to 30 degrees nose low, and abnormal attitude law wakes up!
Might not that interfere with continued trimming nose down automatically and the recovery?

Better to crank the trim down manually to avoid any uncertainty, I think.

RWA
22nd Jul 2011, 04:39
Quoting bubbers44:-


"stall recovery in the 60's lower nose and max power
same for 70's 80's until the 90's.
Then you had to use max power and not lose more than 50 ft for some reason. Secondary stalls became a problem then."


I suspect, bubbers44, that the new (and IMO wrong) procedure was introduced because reduced vertical separation was also approved about that time? That factor might also have made flightcrews very nervous about 'sacrificing' any height in an upset?

mm43
22nd Jul 2011, 05:54
Now imagine you are pushing the nose down to recover the aircraft from the stall, and airspeeds becomes valid, and you get to 30 degrees nose low, and abnormal attitude law wakes up!If they had done that soon enough and initially got rid of the 15° pitch attitude, the AoA would have been approx 20°. Application of a bit of thrust while still continuing to take the nose below the horizon would have quickly brought the AoA into the CL regime. The problem would be to avoid an over (-)rotate and risking another high AoA trying to pull out.

Might be a subject worth running through a spreadsheet and plotting change of AoA over time versus increase of airspeed over the same time.:cool:

wallybird7
22nd Jul 2011, 06:48
BOAC
wallybird - I would ask you to carefully read both the current and old threads on this topic? Your fixation on 'thunderstorms' is out of place based on what we are told by BEA. There is also no firm 'evidence' of any 'thunderstorms' on their route.

There is no evidence that they 'penetrated' or flew near a 'thunderstorm'.

It is shown (in the reports) that their 'choice' to deviate to the west proved to be a better one than other aircraft which went to the east.

BOAC

As a matter of semantics, and my "fixation" on thunderstorms, and no "evidence" of thunderstorms, then just what are they deviating around?

If not thunderstorms?

BOAC
22nd Jul 2011, 07:32
w7 - one more go. See #2103. They were deviating around an area of increased instability in the ITCZ. It may or may not have been a 'thunderstorm' but there is no indication that it was. As I quoted, all the a/c that deviated the other way (East) had a rough ride.

I am detecting a general increase in 'urban legend' again that in general the PF made constant 'nose-up' inputs. This was indeed the report's conclusion for the top of the zoom and the early part of the (stalled) descent, but was NOT the conclusion for the zoom itself. Xcitation's 'bullet points' (last quote in #2096) taken from page 3 of the May report are misleading and are perhaps due to translation problems in that they imply that the inputs were mainly nose up 'from A/P disconnect'. BEA have not produced any substantiating evidence of this. Regarding the 'zoom' they say:

"The PF made nose-down control inputs and alternately left and right roll inputs."

The climb is still unexplained.

sebaska
22nd Jul 2011, 08:56
As a matter of semantics, and my "fixation" on thunderstorms, and no "evidence" of thunderstorms, then just what are they deviating around?

If not thunderstorms?

Just storms? Storms without thunders&lightning?

infrequentflyer789
22nd Jul 2011, 09:11
I am detecting a general increase in 'urban legend' again that in general the PF made constant 'nose-up' inputs. This was indeed the report's conclusion for the top of the zoom and the early part of the (stalled) descent, but was NOT the conclusion for the zoom itself.

Remember that on the bus a nose-up input creates pitch-up demand that stays until countered by same amount of nose-down demand. PF didn't have to make constant nose-up input for a/c to keep climbing - short nose-up input will do it. The later nose-down inputs reduced the pitch and slowed the climb but not enough to get the nose down to get the speed back.

sebaska
22nd Jul 2011, 10:05
There was that "Unidentified" pile of debris to the Northeast in the debris field, I always took that to be the tail feathers.Or, were the PF inputs limited to independent elevators only (to include Roll?) Because the THS couldn't/wouldn't "move"?

If something got jammed there would have been clear traces of such thing in FDR. Similarly if elevator went away then, while active jack could conceivably stay at it's place, the other (redundant one) working in "damping mode" would've got "desynchronized" from the primary one as there would have been no surface to push/pull it. That should be clear on FDR.


RWA:

Why trim didn't change during those nose down actions has been discussed already. There are 2 primary options...
1. Plane went into abnormal attitude law (but there is no tip about that in any BEA statements)
2. Inputs were not significant enough to cause trim change. Some AB engineer or someone other knowing details of A330/A340 control systems could shed more light on that, but nowhere it's said that trim change starts instantly after pitch input. It's perfectly conceivable (and in fact reasonable) that trim starts to change only after stick input is persistent. Note also that it took about 1 minute to get trim from 3 to 13 deg, so one should expect to wait another minute to get it back to 3 by automatic action. If one needs trim to change faster one does have that trim wheel in front of oneself.


Wrt. plenty of time to get that bird out of the fall while at FL100. This was not Cessna 172, this was AF447 heavy. 200tonne bird. Heavy airplanes sometimes get recovered from "falling out of the sky" upset, but it's just that: sometimes.

Back of envelope calculation shows that if they were at -30deg flightpath while at FL100 then maybe they could pull up. 2.5g pullup from -30 flightpath at 200kts true speed takes about 6000ft altitude, but add to that an altitude lost to first regain unstalled AoA (nose down to about -15deg from about +15deg -- it could not happen instantly, and they were falling at ~10000fpm or ~50m/s thus loosing about 150ft every second) could that plane pitch as much while loosing no more that 4000ft? Maybe...
But if they already were at -45deg flightpath (the flightpath angle when they hit the water) they stood no chance at FL100. Pullup itself would take ~8500ft, but pitching down 200t bird by 45deg (from ~+15 down to ~-30) while loosing only 1500ft? I don't see that.

I suspect, bubbers44, that the new (and IMO wrong) procedure was introduced because reduced vertical separation was also approved about that time? That factor might also have made flightcrews very nervous about 'sacrificing' any height in an upset? In the middle of an ocean? Where the traffic is relatively small, and there are significantly horizonally separated airways for the traffic going NE and for that going SW, and where are no planes to be vertically separated from from FL100 up to FL600? Those guys know perfectly well that they can divert by significant amount, they can change level, etc. without any risk of collision.

bearfoil
22nd Jul 2011, 12:01
sebaska

Thanks for the input. There is a possibility that the THS could have become inop and the sensors not suss it. It is a long story, and I'll start by noting the PF's Nose down inputs prior to STALL STALL, at which time he evidently relented, and either held neutral, or back ss.

Nose Down. Again, Nose Down. The airplane is not dropping her nose. (This at the post apogee fall off). Again Nose Down, now the STALL WRN.

Each time the PF inputs some NOSE DOWN, the a/c does the opposite, she starts to nose up, and slows. Finally, with the STALL WARNING, PF is baffled (wouldn't anyone be?)

Under what circumstances would the nose rise with down elevator? Just a few. For one, if, instead of commanding PITCH, the elevators were trimming the THS. How is that possible? Only if the THS had lost integrity with the mount, specifically the jackscrew. Had this occurred, the THS elevator system would perform as an all flying tail, a stabilator.

For the elevators to work in PITCH, the THS must remain resistant to them, that is why it does not trim at elevator deflection speed.

Look, this is but one possibility, and I expect it to be ignored or dismissed, but since it is possible, I think it deserves a look.

See BOAC #2121 re: the climb, and consider how the climb could have been extreme due PF input of NOSE DOWN. The climb is the key. Still looking at mechanicals, and FC.

Lonewolf_50
22nd Jul 2011, 12:26
Bear, I don't have enough info to answer your "?" about what's mounted wear with any confidence. Someone who flies or fixes the A330 might.
As to this:
Just a few. For one, if, instead of commanding PITCH, the elevators were trimming the THS.
How is that possible?
Only if the THS had lost integrity with the mount, specifically the jackscrew.
Had this occurred, the THS elevator system would perform as an all flying tail, a stabilator.

bear, I am confused as to what you are saying. If you move the elevator, you command pitch to one degree or another. What appears to happen, unless in direct law or manual control, is that initial pitch controls are manifested in elevator movement, which is followed up by trim to the THS to put the loads in equilibrium for the new state. An elevator movement up or down will change the shape of the combined airfoil (THS/elevator) any time you do it. Under normal operations, the THS will naturally lag behind the elevator input for any control position change.

Using the trim wheel short circuits that. I understand based on a few posters here having described such an event, that it makes the control via trim wheel less "smooth" for the pilot flying compared to what he is used to.

To suggest that the elevators only trim the THS seems to me a desicription of how the combined system (elevator and THS) does not work. That may be my fault in part, as some pages back I raised the ideas of primary and secondary flight controls, and trim functions. (Maybe at Tech Log thread)

From the block diagram, the change induced by elevator control informs the system of a need, or not, to adjust THS trim to better position that flight control surface for best AoA for desired performance.

If anything got stuck, or was operating in reduced authority, there may or may not have been an audit trail ... but given how much info IS provided to the system via various wires and circuits, I'd be more inclined to believe that a jackscrew failure (or analogous THS positioning machine failure) would trigger either an alert or an ACARS message ... which to date BEA have not released as being the case.

Whatever remains of the tail flight control surface hardware after the slow descent to the depths would be nice to have examined, if only to consider the null hypothesis as part of the process of elimination.

Forensic analysis may be imperfect for a part collecting various deep ocean residue for a couple of years, but a good estimation could be made.

takata
22nd Jul 2011, 13:09
Hi Bear,
Each time the PF inputs some NOSE DOWN, the a/c does the opposite, she starts to nose up, and slows. Finally, with the STALL WARNING, PF is baffled (wouldn't anyone be?)
I really wonder if you don't get a different report than ours. There is actually only two nose-down imputs reported in the whole BEA note:
1) 2:10:16 ... 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...
The first mentions of ND is obviously reducing the vertical speed; consequently, I can't find anywhere that "the aircraft does the opposite, she starts to nose up, and slows".
2) 2:12:02 ... Around fifteen seconds later, the PF made pitch-down inputs. In the following moments, the angle of attack decreased...
The second mentions of ND is obviously reducing the angle of attack; consequently (again), I can't find anywhere that "the aircraft does the opposite, she starts to nose up, and slows".

The obvious issue isn't about what the PF/aircraft did but, quite frankly, about how you are reading this report with such a personal interpretation of a couple of "facts".

At 2 h 10 min 51, the stall warning was triggered again. The thrust levers were positioned in the TO/GA detent and the PF maintained nose-up inputs. The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase.
Following your understanding of "facts", at this point, this aircraft is entering a near vertical dive, don't you think?

jcjeant
22nd Jul 2011, 13:25
Hi,

About THS .. I will repeat myself :)
Be sure that Airbus Industrie have already simulated many parts of the situations where AF447 was involved
They certainly know perfectly if the plane is recoverable with parameters as attitude .. altitude and speed .. and position of the THS at 13° up of AF447
And those tests can (maybe) be performed by some members (A330 pilots) of this forum
Apparently no one made it so far.

bearfoil
22nd Jul 2011, 13:49
Lonewolf50

Offered only insofar as to what could explain a Pilot pulling back when Confronted with STALL warn or actual Stall.

The elevators change the Pitch of the A/C acting through the Horizontal Stabiliser. This would not happen if the HS was free to move where the elevators put it. 'eg'. the elevators would change the AoA of the HS rather than the a/c.

So IF the Horizontal Stabiliser was not connected to its jackscrew (which "Positions it internally"), it would deflect to whichever angle the elevators put it. This would in turn change the Pitch of the a/c, but opposite to ss input. Down elevator pushes the trailing edge of the HS UP, climbing the a/c.

I don't wish to make any claim re:447. AGAIN, I think it is worth a look, if only to better understand the way the a/c functions.

The PF WAS making ND input, and the STALL WARN tripped. It is logical (though perhaps not correct in this case) to assume the effect of his command was counter to his expectation (And to ours).

So, in the failure case (separated jackscrew), the a/c is reacting to the THS' position, which is commanded by "trimming" elevators, rather than "commanding" elevators. Simply drop a step in the arrangement of conventional trim tab, elevator, and HS. Eliminate the HS, and what is left, is the arrangement on all THS flying a/c!

Aside.... BEA say "..and remained in that position to impact..." They are speaking of the THS, planted at 13. What holds it there? Perhaps not the Pilot's NU, perhaps not Hydraulics, active or lock. Perhaps airflow.

sebaska. I believe the two motors are positioned on the same jack. Perhaps not.

sebaska
22nd Jul 2011, 16:06
Under what circumstances would the nose rise with down elevator? Just a few. For one, if, instead of commanding PITCH, the elevators were trimming the THS. How is that possible? Only if the THS had lost integrity with the mount, specifically the jackscrew. Had this occurred, the THS elevator system would perform as an all flying tail, a stabilator.

So IF the Horizontal Stabiliser was not connected to its jackscrew (which "Positions it internally"), it would deflect to whichever angle the elevators put it. This would in turn change the Pitch of the a/c, but opposite to ss input. Down elevator pushes the trailing edge of the HS UP, climbing the a/c.

I'm sure that such severe misbehaviour would stand out in FDR recording. THS diconnected from its jack would be banging up and down dependent on elevators position. This would be accompanied with violent pitch changes and high g loads. If the whole thing would not separate almost immediately. Then how both left and right THS would fail at the same time? Or is there just one jack for both of them?


sebaska. I believe the two motors are positioned on the same jack. Perhaps not.

A I understand each elevator has two jacks (It has been described here recently). Normally one of those is active while the other is in "damping mode" (i.e. gets pulled/pushed instead of pushing/pulling).
THS has one jack with two motors. But I understand it's one for each side. But i could be wrong.

bearfoil
22nd Jul 2011, 16:38
I submit that such misbehaviour did reach the DFDR, and we are seeing it, per BEA.

Do not be too quick to dismiss the THS/Elevator system as wild, with great Pitch excursions. On the contrary, many aircraft are controlled w/o jacks on the HS. With articulating elevators and a freely pivoting HS, Pitch is quite manageable, and all that is necessary is a program that can retain precise Trim for the AoA of the assembly as a whole.

The problem would be in the Flight management from the cockpit. Immediately, Pitch would reverse, but control could be maintained, even good control, and Trim. It would take a brilliant pilot, similar to the rare excursions experienced by a PF taking off with elevators reversed. Ab Initio, ad lib, as it were.

Here, I am looking for a possibility that would explain not only unusual behaviour on the part of PF, but also the aircraft.

ACARS was a LEAK. BEA affirmed what was made public. They even explained it. There was that GAP, however. And no further comment from the authority.

I have been doubtful and suspicious of ACARS as leaked from the git. No way of knowing if all of ACARS exists, is known by BEA, or some other.

for now, I am looking for reasons to support any theory that embraces such aberrant behaviour, as reported.

Thanks for taking the time to respond.

Now, some HF. One or the other or both of the cockpit crew wanted the Captain's presence, NOW. It could not have been UAS, Weather, or any of the normal suspects, imho.

Some one removed his bars (figuratively), placed them on the deck, and called for help from Captain. It is not in the nature of Pilots to do that, unless the situation is irrecoverable. Such as, an aircraft that is behaving wildly, unpredictably, and deadly.

xcitation
22nd Jul 2011, 16:54
@Bearfoil
IMHO the suggested catastrophic failure of the THS is over-reaching. Such a failure of control surface would result in well documented "smoking gun" errors. Furthermore the a/c response to control inputs appears to have been reasonable considering the stall condition and weather. For a brief description of THS check out Section 5 the A330 brochure here (http://www.smartcockpit.com/data/pdfs/plane/airbus/A330/misc/A330_Flight_Deck_and_Systems_Briefing_For_Pilots.pdf).

@Wallybird7
Thunder and lightning comments are IMHO of less merit. The primary threat here is convection (up/down draft, shearing resulting in excessive strain to the airframe and disruption to flight path/attitude) and precipitation (causing icing on the airframe and affecting thrust). Lightning can occur many miles away from the convective storm and can be independent event. Lightning strike on a/c is a very rare and generally benign event.

bearfoil
22nd Jul 2011, 17:08
I submit that to some extent, any conjecture is true to your definiton of "over-reaching". BEA have not offered an explanation of any kind. Have you noted that? Likewise no theory. They have allowed (encouraged?) speculation. The alternative is "Wait for the final report".

I thought we were past that. I think any attempt to give the discussion "guidelines" in the absence of any attempt to provide reasonably complete data (BEA), is presumptuous. If my posts are bizarre, upsetting, etc. I rely on the mods to edit them. I have always welcomed mods input or editing; I am here by 'invitation' only. I have even edited myself, or banned me temporarily. I have utmost respect for all who post here, everyone.

I am unable to put together even such as is found here, except to take in that which is accomplished for me.

Over my Head?. Boy Howdy.

xcitation
22nd Jul 2011, 17:19
@Bearfoil


Now, some HF. One or the other or both of the cockpit crew wanted the Captain's presence, NOW. It could not have been UAS, Weather, or any of the normal suspects, imho.


Are you saying that 2 stall warnings at Cruise alt, ALT LAW, ECAM errors, unknown speed were not significant enough to call Capt to flight deck?
:confused:

takata
22nd Jul 2011, 17:22
So IF the Horizontal Stabiliser was not connected to its jackscrew (which "Positions it internally"), it would deflect to whichever angle the elevators put it. This would in turn change the Pitch of the a/c, but opposite to ss input. Down elevator pushes the trailing edge of the HS UP, climbing the a/c.
Hence, following your own logic, with all those sustained nose up imputs recorded, this aircraft would not stall at the first place... as she would dive straight into the sea!
Beside, there isn't one but three drive systems working the THS actuator : one electrical, one hydraulical, and one mechanical... all of them have anti-jamming devices avoiding that THS actuator could get free in case of whatever imaginatory undetected failure you might be thinking about. It is quite a big screw planted into the tail and quite a big piece of steel surmounting it.

Lonewolf_50
22nd Jul 2011, 18:27
As I read the system diagram, you won't be able to move the THS inflight without hydraulic pressure.

The mechanical link interacts with the hydraulic motor (jack?) to move the THS up or down via the trim wheel commands.

Hydraulic motors from blue and/or yellow hydraulic systems power the jack.

If the electrical controls are still working (as one would expcet in Alternate Law) an electric motor tells the hydraulic motor/jack which way to move, and how much. (Notation a few posts up on damping appreciated, I finally "got" how that works in normal operations).

If I misunderstand what moves the THS, I'd appreciate any corrections so I can annotate my slides.

bearfoil
22nd Jul 2011, 18:42
I think trim wheel and EFCS power the THS similarly, but via different inputs?

The damper Hyd Motor, and the actuator motor are on the same screw (per machaca's pic). My understanding is that they can alternate roles.

The Elevators are independent of one another, obviously, there is no through hull penetration for an elevator "spar". Each hangs off the TE of the HS.

The HS is attached to a continuous spar, making each leaf a part of the solid slab.

I do not know if the elevators deflect independently, (Roll?).

I cannot 'copy' my tail innards pic. It's in here somewhere, sorry.

mm43
22nd Jul 2011, 20:14
THS - Screw Jack

http://oi56.tinypic.com/2reql9h.jpg

jcjeant
22nd Jul 2011, 21:17
Hi,

Thunder and lightning comments are IMHO of less merit. The primary threat here is convection (up/down draft, shearing resulting in excessive strain to the airframe and disruption to flight path/attitude) and precipitation (causing icing on the airframe and affecting thrust). Lightning can occur many miles away from the convective storm and can be independent event. Lightning strike on a/c is a very rare and generally benign event. Ironically .. the thunderstorm thingy was the first words tell by Gourgeon (AF CO) at first press meeting as explainations after AF447 crash.
This was immediately dismissed by some experts as a cause of the crash...
Certainly some had an agenda .. but who ? :)

bubbers44
22nd Jul 2011, 22:24
Hopefully soon we will get a final report from BEA to make this an informative thread again. It has drifted into oblivion recently. Most everything brought up recently goes against the keep it simple rule. We know they had UAS and they crashed. Jackscrews, thunderstorms, severe updrafts and triple attitude indicator failures are really reaching.

wallybird7
23rd Jul 2011, 01:16
Hi,

Quote:
Thunder and lightning comments are IMHO of less merit. The primary threat here is convection (up/down draft, shearing resulting in excessive strain to the airframe and disruption to flight path/attitude) and precipitation (causing icing on the airframe and affecting thrust). Lightning can occur many miles away from the convective storm and can be independent event. Lightning strike on a/c is a very rare and generally benign event.
"Ironically .. the thunderstorm thingy was the first words tell by Gourgeon (AF CO) at first press meeting as explainations after AF447 crash.
This was immediately dismissed by some experts as a cause of the crash...
Certainly some had an agenda .. but who ? http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/smile.gif "

Allow me to speculate: If every airline in the world had a policy stating that Avoiding Thunderstorms was the prudent thing to do, and AF did not -- then I feel confidant that they would dismiss it as a Probable or Contributing cause factor. Especially since they have no more proof as to the real Probable Cause than we do.

RWA
23rd Jul 2011, 05:22
Quoting BOAC:-


The climb is still unexplained.

Came across this article quoting an Airbus pilot at some length. It offers a (pretty hair-raising) explanation of what MAY have happened. Obviously there's no way I can 'authenticate' it - and I didn't try to delete the expletives! :) - but I hope it's of interest.

An Airbus Captain’s Take on the Air France Disaster | Autopia | Wired.com (http://www.wired.com/autopia/2011/07/an-airbus-captains-take-on-the-air-france-disaster/)

wallybird7
23rd Jul 2011, 06:07
It's right on target!

Totally agree!

WojtekSz
23rd Jul 2011, 06:08
...One or the other or both of the cockpit crew wanted the Captain's presence, NOW. It could not have been UAS, Weather, or any of the normal suspects, imho.
Some one removed his bars (figuratively), placed them on the deck, and called for help from Captain. It is not in the nature of Pilots to do that, unless the situation is irrecoverable. Such as, an aircraft that is behaving wildly, unpredictably, and deadly. ...or you are following previous orders to be called back if the situation calls for it. Remeber we are taking about French plane with all French crew following clearly set 'power index' rules.

if PF knows that the situation is irrecoverable than CRM would require him to voice it and communicate with the PNF - the trace of such behaviour is when the plane has practically already fallen out of othe sky at 2:13:47 ie some 40 sec before impact.

Zorin_75
23rd Jul 2011, 06:55
Came across this article quoting an Airbus pilot at some length. It offers a (pretty hair-raising) explanation of what MAY have happened.
The key ingredient most everyone seems to be overlooking: The flight control laws of an Airbus (http://www.airbusdriver.net/airbus_fltlaws.htm).
Yes, exactly, maybe he should look them up. :rolleyes:

ZimmerFly
23rd Jul 2011, 09:13
Editor’s note: Air France Flight 447 was en route to Paris from Rio de Janeiro when it went down over the Atlantic Ocean on June 1, 2009, killing all 228 people aboard. It took 11 months to locate the Airbus A330-200’s black box data recorders

Their standard of editing reflects the standard of the article.....June 2009 until May 2011 looks a lot more like 23 months ! :8

Hyperveloce
23rd Jul 2011, 18:47
Quoting BOAC:-

Came across this article quoting an Airbus pilot at some length. It offers a (pretty hair-raising) explanation of what MAY have happened. Obviously there's no way I can 'authenticate' it - and I didn't try to delete the expletives! :) - but I hope it's of interest.

An Airbus Captain’s Take on the Air France Disaster | Autopia | Wired.com (http://www.wired.com/autopia/2011/07/an-airbus-captains-take-on-the-air-france-disaster/)

Hello there,
I understand the risk underlined in the above Wired article:
- both the Pitot ram tube and its drain freeze, hence the airspeed derived from this compromised Pitot becomes an increasing function of the altitude,
- the flight enveloppe protection laws tend to increase the altitude if the airspeed increases too much
... and the interaction between these two phenomena makes a diverging control loop (if there is an altitude perturbation, say an increase, the airspeed increases too and the protection law commands an increase of altitude, etc...)

But in the AF 447 case:
- the early left PFD and the ISIS airspeeds inconsistency was only 1 min and the flawed airspeed does not seem overestimated but largely underestimated
- the flight protections (high speed prot) are lost in ALT2 triggered by a NAV disagreement
- the maintained NU inputs are the PF inputs

So how the Wired hypothesis can be applied to the AF 447 case ?

bearfoil
23rd Jul 2011, 18:54
So, the a/c compensates in control of the airframe. But in reading (computing) altitude, doesn't it rely on a/s (as well as Statics).

How does the BEA harvest "altitude" information? Is it reliable? (The altitude, not BEA, sorry).

wallybird7
23rd Jul 2011, 20:49
Bubbers44
"W7 you seem warped"

How so?

bubbers44
23rd Jul 2011, 22:40
"Whether the aircraft was struck is the main item of concern, and it appears no such event occurred."

All that refers to is the fact that the plane was probably not struck by lightning.



It still confirms the fact that strong updrafts were probable as well as turbulence and that alone was enough to cause the pilots to lose control of the airplane. Which they did.


I guess a stream of irrational posts like this inspired warped. No data, just personal opinion. We would be losing aircraft every day if your statement was true.

Poit
24th Jul 2011, 00:46
Hello there,
I understand the risk underlined in the above Wired article:
- both the Pitot ram tube and its drain freeze, hence the airspeed derived from this compromised Pitot becomes an increasing function of the altitude,
- the flight enveloppe protection laws tend to increase the altitude if the airspeed increases too much
... and the interaction between these two phenomena makes a diverging control loop (if there is an altitude perturbation, say an increase, the airspeed increases too and the protection law commands an increase of altitude, etc...)

But in the AF 447 case:
- the early left PFD and the ISIS airspeeds inconsistency was only 1 min and the flawed airspeed does not seem overestimated but largely underestimated
- the flight protections (high speed prot) are lost in ALT2 triggered by a NAV disagreement
- the maintained NU inputs are the PF inputs

So how the Wired hypothesis can be applied to the AF 447 case ?

Hi Hyperveloce,

Yes, on reading the article I agree with your comments. The aircraft was not climbing prior to Alternate Law, and all subsequent NU inputs were from the PF's controls (that's pretty clear from the BEA report).

It worries me that this guy is (supposedly) a captain, he appears to have less understanding of this case than many of the 'punters' he openly dismisses.

bearfoil
24th Jul 2011, 01:29
Remember the Captain (PF) of Q32 describing "explosions" in #2? Bad form, we were told they were to be called "bursts". Is he less a Captain?

I haven't a clue if this Captain (wired) is a Captain, or Jimmy Hoffa. He sounds legit, but then "they" would want him to act that way?

Wired's theory is spit simple that of The Shadow, who hung around a bit like Captain Burkill on BA038. Are they the same "Captain"? I'd say no, there are perhaps six main theories and several sub theories that sound one to the next acceptable.

Bad weather, a fact. (Watch someone demand a definition of "bad").
Iffy Pitot Probes, a fact. (Hollywood couldn't make this up.)
Night time. (Demonstrable, and no Horizon? just a guess).
UAS. Not a fact, but most likely? It has its own name, so it must be important, but not important enough to qualify Thales for an AD. (Fact).
No speeds to speak of, and PF caught the a/c as a bit of a surprise, (thought to be a fact). He moved the stick, contra the suggested procedure offered by PJ2, whose input here is the Gold Standard.
An absurd and deadly climb of 3000 feet ending in a relatively (almost) recovered airframe, but instead she squats down and does the mush for seven miles.

This is all pretty true, I think. I am told the Judge has sequestered all evidence produced by BEA; it is simply not going to be produced. (Rumor)

Sounds unlike a group whose goal is the TRUTH, and SAFETY. It can't be important, or they would make it public, or order some procedural hoorahs, yes! So, no worries, nothing to see.

Techman
24th Jul 2011, 02:13
I have tried really hard to make sense of Bearfoil's posts as I figured someone so prolific a poster must have something important to say. All I see are lots of words used to say nothing. It is like listening to a politician answering a question.

Do I need a decoder ring and is it worth the price of a cereal box to get one?

Poit
24th Jul 2011, 04:13
Techman,

LOL, I'm inclined to agree, I was slightly baffled by that last post as well.

'Smile and nod' might be an appropriate answer.

RWA
24th Jul 2011, 05:25
Quoting Hyperveloce:-


the maintained NU inputs are the PF inputs


Not your fault, Hyperveloce, because the BEA Note leaves so much out. But the only mention of a 'left noseup input' at any stage before the upset is this:-


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.


The next relevant entry, referring to at least 11 seconds later, says:-

At 2 h 10 min 16, the PNF said "so, we’ve lost the speeds" then "alternate law […]".

Had the PF maintained a 'left noseup input' throughout those eleven seconds the aeroplane would probably have been 'standing on a wing.' But the PNF appears to have been (relatively calmly) going on doing his job and reading and passing on the messages appearing on his screen. That suggests to me that the PF had in fact merely corrected a tendency to roll after the autopilot signed off, and then levelled off and followed the prescribed procedure of 'flying pitch and power.'

The next entry in the BEA note (with no time stated) says:-

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.

No mention of any 'nose-up inputs' - indeed, that entry strongly supports the view that the climb was 'uncommanded' and that the PF took appropriate action to counter it?

The PF is reported, much later on, as maintaining 'noseup inputs,' but that was after the stall had occurred. And, as I said earlier, I think that the most likely reason for those is that the pilots thought for quite a while that they were in a dive rather than a stall.

So IMO, as BOAC said, "The climb is still unexplained."

Poit
24th Jul 2011, 05:50
RWA,

Would you not agree that the nose-up request was from the pilot flying (the left part is irrelevant after had correct the roll right and not necessary for the report). Also, you are quite incorrect about 'next mention' of nose up inputs being 'quiet some time later'...do your research mate:

- 2h 10m 51s PF maintained nose up inputs;
- Around 15 second later the PF continued to make nose up inputs;

I can keep quoting, but the most important one is in the 'New Findings' section:

- The inputs made by the pilot flying were MAINLY NOSE UP.

Hyperveloce was quite justified in what he said. In this case, it is 'your fault' mate, do your research.

TioPablo
24th Jul 2011, 18:59
Greetings to you all,
Reading the last stream of posts (were I keep seeing a redundant quoting of BEA´s interim report), it came to me that it would be a nice idea to refresh some basics about reconfigurable Control Systems and a good reading while waiting for BEA´s next report.
The paper covers CS in a general way, but FCS and AFCS are also addressed.

http://users.encs.concordia.ca/~ymzhang/publications/ARC32-2-98Zhang_pp.229-252.pdf (http://users.encs.concordia.ca/~ymzhang/publications/ARC32-2-98Zhang_pp.229-252.pdf)

Kalium Chloride
25th Jul 2011, 11:33
New interim report to be published on 29 July.

jcjeant
25th Jul 2011, 13:38
Hi,

Indeed (press)
Vol Rio-Paris : rapport vendredi sur "les circonstances exactes" du crash - LeMonde.fr (http://www.lemonde.fr/societe/article/2011/07/25/vol-rio-paris-rapport-vendredi-sur-les-circonstances-exactes-du-crash_1552671_3224.html)

Le Bureau d'enquêtes et d'analyses (BEA) français a annoncé, lundi, qu'il publierait vendredi un nouveau rapport présentant "les circonstances exactes de l'accident" du vol d'Air France AF447 Rio-Paris qui s'était abîmé en juin 2009 au large du Brésil, faisant deux cent vingt-huit morts.The Bureau of Investigation and Analysis (BEA) French announced on Monday it would issue a new report Friday with "the exact circumstances of the accident" of Air France flight AF447 from Rio to Paris, which had damaged in June 2009 off the coast of Brazil, making two hundred and twenty to eight dead.

And .....
Le Figaro - France : AF 447 : le rapport d'étape de l'accident publié vendredi (http://www.lefigaro.fr/actualite-france/2011/07/25/01016-20110725ARTFIG00350-af-447-le-rapport-d-etape-de-l-accident-publie-vendredi.php)

petermcleland
25th Jul 2011, 14:34
I have tried really hard to make sense of Bearfoil's posts as I figured someone so prolific a poster must have something important to say. All I see are lots of words used to say nothing. It is like listening to a politician answering a question.

Do I need a decoder ring and is it worth the price of a cereal box to get one?

You can always do what I have done and put him on your Ignore List :)

Lonewolf_50
25th Jul 2011, 14:54
Tio Pablo, thanks for that link. A bit rough going, but worth the read nonetheless.

RWA
26th Jul 2011, 08:37
Sorry we seem to be disagreeing so much, Poit.

Quoting Poit:-


Would you not agree that the nose-up request was from the pilot flying (the left part is irrelevant after had correct the roll right and not necessary for the report).

You’ve flown light stuff, same as me. You’ll know that one almost never uses the stick in one dimension, ‘coordinate the controls’ is the rule. A bank usually entails a loss of lift and also produces a turn. My best guess is that, in order to get back on course and also maintain height, the pilot put on opposite bank and also used a touch of up elevator – and then levelled out. All perfectly normal. And, as I also said the PNF then read out and cancelled a couple of messages, in a pretty calm manner; if the PF was busy standing the aeroplane on its tail the PNF would surely have been saying different things (to say the least :))?

(In this connection, I dislike the tendency of some (particularly that newspaper article) to suggest that the PF was ‘inexperienced.’ If you look him up, you’ll find that he had the best part of 3,000 hours in his logbook, including about 850 on the A330).


"Also, you are quite incorrect about 'next mention' of nose up inputs being 'quiet some time later'...do your research mate:"

Don’t recall saying that? I thought I wrote, ‘much later on’? The BEA’s (very thin) report times the ‘left noseup’ command at ‘2 h 10 min 05.’

The next ‘event’ the BEA describes is the ‘zoom climb.’ No mention of any noseup inputs before or during that; indeed it describes nosedown inputs. All the evidence is that the PF countered the climb and pretty well got the aeroplane back to level flight. The next event is timed as follows:-


“At 2 h 10 min 51 , the stall warning was triggered again. The thrust levers were positioned in the TO/GA detent and the PF maintained nose-up inputs.”

I make that 46 seconds between noseup inputs? Surely that’s ‘much later on’ in the context of an accident that only took about four minutes from start to finish?

May help if I explain that I tend mentally to break this (and any other) accidents down into phases. Lacking proper information form the BEA, I currently see these as follows:-

1. ‘Signoff’:- AP/ATH disconnect, pilot takes manual control, corrects an uncommanded bank, and begins flying ‘pitch and power.’

2. ‘The climb’:- No stick input either way at first. Then nosedown to arrest the steep climb.

3. ‘The stall’ – stall warning sounds, pilot applies standard ‘stall avoidance’ procedure at that time (apply TO/GA power and seek to minimise altitude loss). Stall warning stops.

(One thing that can’t be ‘fitted in’ to the various phases, in that we don’t know when it occurred, is that at some time during one of these phases, the THS wound itself up to ‘full up.’ Typically, the BEA note refers to it taking ‘about 1 minute’ but it doesn’t say which minute. I’d appreciate other people’s opinions at to when they think it happened?).

4. ‘The free-fall’ – aeroplane begins losing height at 10,000 feet per minute. I’m on record that my own view, on present evidence, is that the pilot(s) thought that the stall avoidance had worked and that they were in a dive, not a deep stall.

5. ‘The attempted recovery’ – somewhere above 10,000 feet, power was reduced (again, the BEA doesn’t say when) and the PF applies ‘pitchdown inputs.’ Angle of attack improves and the speed indications return. BUT – the stall warning sounds again…….

6. ‘The crash’ – the aeroplane belly-flops into the Atlantic.

To the best of my knowledge, that’s all we know so far. Comments, additional points, corrections, further information from anyone all welcome.

Mr Optimistic
26th Jul 2011, 08:45
5. 'nose up inputs' ?

Good memories
26th Jul 2011, 09:28
Hello, just read in the Var Matin that Friday 29th the BEA is coming out with a third report and a analysis. Let's hope we get some more facts. Of course I am thinking about the beloved ones of the deceased but also about the pilots who are flying these aircraft daily.

Good memories
26th Jul 2011, 09:42
Le troisième rapport d'étape du BEA sera publié le vendredi 29 juillet 2011. Ce rapport présente les circonstances exactes de l'accident avec des premiers points d'analyse et de nouveaux faits établis à partir de l'exploitation des données des enregistreurs de vol.

A cette occasion, un point presse sera organisé au BEA à 14 h 30 le même jour.

RWA
26th Jul 2011, 09:56
Quoting Mr Optimistic_

5. 'nose up inputs' ?

Many thanks, Mr O, edited! :)

iceman50
26th Jul 2011, 10:09
RWA

For the umpteenth timepilot applies standard ‘stall avoidance’ procedure at that time (apply TO/GA power and seek to minimise altitude loss). that is :mad:!

Give it a break your theory and misinterpretations are wrong, you are like a broken record and never reply to the posts that contradict you. You wait a few days / posts and post the same rubbish again. If you have nothing NEW to say don't say anything.:ugh::ugh:

You need to read and digest how the airbus flight controls work not how you think they work.

RWA
26th Jul 2011, 10:33
Quoting iceman50:-


that is :mad:!

Give it a break your theory and misinterpretations are wrong, you are like a broken record and never reply to the posts that contradict you.

On the contrary, I answered your last (also somewhat abusive) post, with a source, in my Post 2086 above.


"Investigators have been left attempting to explain why the crew of Air France (http://www.flightglobal.com/landingpage/air%20france.html) flight AF447 failed to recover the Airbus A330 (http://www.flightglobal.com/landingpage/airbus%20a330.html) from a high-altitude stall, a predicament which has been the subject of a recent revision of safety procedures.

"The revision concentrates on placing greater emphasis on reducing excessive angle of attack - the critical characteristic of a stall - rather than the classical approach of training pilots to power their way out of a near-stall with minimum loss of altitude.

A formal document detailing the rationale for the revision points out:
"There have been numerous situations where flight crews did not prioritise [nose-down pitch control] and instead prioritised power and maintaining altitude."

Operational experience has shown that fixating on altitude, rather than the crucial angle of attack, can result in an aircraft stalling.

Revised stall procedures centre on angle-of-attack not power (http://www.flightglobal.com/articles/2011/05/28/357321/revised-stall-procedures-centre-on-angle-of-attack-not.html)

If Flightglobal (and I) are wrong, please inform us what the recommended procedure actually was back in 2009, and what changes were made recently?

BOAC
26th Jul 2011, 10:44
For the umpteenth time Quote:
pilot applies standard ‘stall avoidance’ procedure at that time (apply TO/GA power and seek to minimise altitude loss).
that is http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/censored.gif! - maybe have a glance at http://www.pprune.org/tech-log/415373-new-airbus-stall-recovery-procedure.html ? It may be of interest to you.

iceman50
26th Jul 2011, 11:10
BOAC

It is NOT new, it has just been re-emphasised by Airbus Boeing regulators etc as some pilots / checkers were thinking like RWA as in maintain ALTITUDE. The procedure being continually mentioned by RWA was recovery from low speed NOT a stall and even that did NOT mention MAINTAIN altitude. There again perhaps I have been teaching and checking it incorrectly for the last 10 years on the A330 / 340 and been taught stall recovery incorrectly for the 30 years before that.

stepwilk
26th Jul 2011, 11:12
(In this connection, I dislike the tendency of some (particularly that newspaper article) to suggest that the PF was ‘inexperienced.’ If you look him up, you’ll find that he had the best part of 3,000 hours in his logbook, including about 850 on the A330).

For a Cessna 172 pilot, this is "experienced." For an air-transport pilot, not.

GarageYears
26th Jul 2011, 11:54
RWA:

1. ‘Signoff’:- AP/ATH disconnect, pilot takes manual control, corrects an uncommanded bank, and begins flying ‘pitch and power.’

So where is the evidence there was any attempt at pitch and power at this point??? You have simply made this up. We are simply told there was a roll correction and nose up input. Followed by a 3000 foot climb...

There is no mention of any attempt to control power until some point later when the misguided TO/GA selection was made. At least that's the only mention of any power adjustment I can find in any segment of the BEA note until much later when power was reduced.

takata
26th Jul 2011, 12:04
Hi,
3. ‘The stall’ – stall warning sounds, pilot applies standard ‘stall avoidance’ procedure at that time (apply TO/GA power and seek to minimise altitude loss).
Where did you get that?
There is NO such a "Standard stall avoidance procedure" for A330 due to NORMAL LAW flight envelope protections. If you want to refer to what is really relevant, you'll need to check into the "Abnormal Operations" related to ALTERNATE LAW, where stall avoidance procedures are described.

Here, you'll learn what the correct procedure is 3.04.27 page 6 (Rev 18, 2003). There is two cases: low speed and high altitude.
a) low speed: Apply TOGA and (at the same time) reduce pitch angle (angle-of-attack).
b) high altitude: Relax back pressure on sidestick (reduce angle-of-attack).

Where is then this "standard procedure" you were talking about for high altitude stall warnings:
=> Apply TOGA and maintain back pressure on sidestick !?!
Both actions recorded are wrong for the situation: TOGA is not needed, neither is this pulling up.

This was the second stall warning, the first was ignored or responded by a pitch up if volontary applied. There is no trace of your:
1. ‘Signoff’:- AP/ATH disconnect, pilot takes manual control, corrects an uncommanded bank, and begins flying ‘pitch and power.’
Pitch was wrong and power was not unlocked (no trace of this in BEA narrative). You are retaining bank correction without pitch correction. Why are you making up this stuff?

Same about this:
At 2 h 10 min 51, the stall warning was triggered again. The thrust levers were positioned in the TO/GA detent and the PF maintained nose-up inputs. The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase. [I]The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight.
Around fifteen seconds later, [~0211:06]
How can you say that you don't know when THS moved to 13°?
This is obviously timmed starting at or closely after 0210:51 and then ended also close to 0211:51.

If Flightglobal (and I) are wrong, please inform us what the recommended procedure actually was back in 2009, and what changes were made recently?
Of course you are completely wrong.
What changed was the emphasis on Pitch rather than Thrust, as large thrust increase may have an adverse effect on pitch reduction at low speed. At high altitude, it doesn't change a glitch as stall warnings would be triggered at the onset of buffet, likely at an already high Mach, without many excess thrust available, hence only a question of AOA at the limits of the safe flight envelope.
Check by yourself the relevant part of A330 FCOM in use before 2009:

http://takata1940.free.fr/stall1.jpg

BOAC
26th Jul 2011, 13:09
I suspect that like me, none of the contributors here of late actually know what Air France taught for recovery from the approach to a stall in the A330 in those days, nor how much 'reliance' was instilled in crews in the infallibility of the AB in not 'letting you stall'. It is worth noting that unlike the impeccable Iceman, some trainers were NOT teaching things correctly - in the UK at least.. This is the first para from post#14 in my link (with my emphasis) from April 2010

A very good document from British CAA that has a lot in common with the new procedure:

Applicability: RETRE, TRIE, TRE, SFE, TRI, SFI
Effective: Immediate
STALL RECOVERY TECHNIQUE
1 Recent observations by CAA Training Inspectors have raised concerns that some instructors (both SFIs and TRIs) have been teaching inappropriate stall recovery techniques. It would appear that these instructors have been encouraging their trainees to maintain altitude during recovery from an approach to a stall. The technique that has been advised is to apply maximum power and allow the aircraft to accelerate out of this high alpha stall-warning regime. There is no mention of any requirement to reduce the angle of attack – indeed one trainee was briefed that “he may need to increase back pressure in order to maintain altitude”.


Wait until 29 July?

takata
26th Jul 2011, 13:29
Hi BOAC,
I suspect that like me, none of the contributors here of late actually know what Air France taught for recovery from the approach to a stall in the A330 in those days, nor how much 'reliance' was instilled in crews in the infallibility of the AB in not 'letting you stall'.
Maybe a look at AF A330 documentation can give you a hint about that?
In fact, it is in English and they used Rev.24 of the procedure with three cases:
- lift off (low speed)
- flight phases after lift off (low speed)
- high altitude

This "Infallibility" legend of the Airbus "will not let you stall" is certainly not part of this aircraft documentation, check by yourself:

http://takata1940.free.fr/AFstall0.jpg
http://takata1940.free.fr/AFstall1.jpg

BOAC
26th Jul 2011, 14:23
This "Infallibility" legend of the Airbus "will not let you stall" is certainly not part of this aircraft documentation, check by yourself: - That was a silly comment. Are you seriously suggesting that AB would have put those words in the manual? I would not even expect Ziegler to do that - spout it, yes, but print it? No.

What is your airline experience as pilot, by the way - hours, types? Your ability to produce manuals, graphs and quotes is indeed impressive, but...................

Has the thought crossed your mind that some of the some instructors (both SFIs and TRIs) most probably would have had similar words to the AB page in their manuals - and STILL taught otherwise? Your faith is touching, to say the least, and to come from a world where everyone (and, of course, everything) performs faultlessly must indeed be wonderful.

sebaska
26th Jul 2011, 14:49
BOAC:
Why ad hominem? :=

Besides, where it's written that those 'some instructors' are/were AB330 instructors? Or from AF?

bearfoil
26th Jul 2011, 15:28
If uncommanded by PF (or a/c), the climb may have been addressed with PF's 'Nose Down inputs'. I think BEA have not specifically timed those.

Likewise, he would not advance Throttles (he did not).

The second STALL WARN, could actually be predicting the STALL that resulted from loss of energy in this climb (which thus far is not described as to origination). The AoA (not necessarily PITCH) would increase as the Plane slowed, independent of elevators that had lost their effectiveness anyway. As the Plane dropped Nose (Either as a result of controls OR STALL), the AoA would reduce, hence TOGA and 'backstick relief' as the a/c "STALLED". At this point, had PF done nothing, he may have recovered? (No TOGA, no 'back pressure' held). Saying the pilots did not know they were Stalled is presumptuous.

At this point it is not determined if NU inputs are slight (inadvertent) pulls by PF, and not a back (climb) command. It could indeed be a trained APPROACH TO STALL recovery, at a very inopportune time.

Lonewolf_50
26th Jul 2011, 15:55
If uncommanded by PF (or a/c), the climb may have been addressed with PF's 'Nose Down inputs'. I think BEA have not specifically timed those.
Bear, to be clear, that depends on the duration and frequency of nose down inputs as counters to nose up inputs (per how a Sidestick works) which detail is still vague. The BEA seems confident that at least initial climb was initiated by a nose up movement of SS.
The second STALL WARN, could actually be predicting the STALL that resulted from loss of energy in this climb (which thus far is not described as to origination). The AoA (not necessarily PITCH) would increase as the Plane slowed, independent of elevators that had lost their effectiveness anyway.
Huh?
The climb slowed the plane. Since power was not initially reduced, climb came from pitch up, so ... AoA change was due to ... drumroll ... pitch up. You with me? It has been suggested that when TOGA was selected later in the event chain, nose pitched up more due to how planes like this fly. This tends to increase AoA if not countered by the appropriate pitch adjustment (n-d) to accompany the power increase. This is Flying 101, and would be called for if in alternate versus normal law. There is evidence that pilots were aware of being in alternate law. Not sure of the granularity with which BEA can parse the data from FDR ... we shall see. I suspect it correlates well enough.

bearfoil
26th Jul 2011, 16:01
Sorry Lonewolf.

I am posting on the other thread, and forgot to mention I assume a substantial UP Draft for the climb, consistent with Harry Mann's proposal that the Right wing drop may be a Tip Dip into Vertical Airmass by Left wing. See, if uncommanded, PF would input Nose Down, to maintain altitude (I reasonably assume he did not want to climb!).

Had a stroke last year, and sometimes (usually?) I leave out key bits. And include some extraneous ones!

jcjeant
26th Jul 2011, 16:26
Hi,

You with me? It has been suggested that when TOGA was selected later in the event chain, nose pitched up more due to how planes like this fly.

At the altitude where was the plane .. with the throttle setting he have (before the PA disconnect) I suppose the difference of push by the engines will be minimal when throttles set to TOGA .. and so the nose up effect will be no significant
I understand that at low altitude a TOGA set will produce a significant nose up ...... not at high altitude.

RetiredF4
26th Jul 2011, 17:19
There seem to be a lot of different stall recovery procedures on the market from the time before AF447.

@takata and Iceman

I think, the revised stall recovery procedure, implemented due to some LOC´s without successfull recovery by A+B aircraft made a lot of sense, so it seems to be short sighted to assume the old procedures had nothing to do with the training before AF447 and therefore the applied procedures of AF447. The emphasis of the old procedures was placed on speed increase and maintaining altitude, whereas the revised procedures aim on reducing AOA firsthand and deal with altitude when AOA and speed allows further maneuvering. There are a lot of differences to the new procedures (http://www.ukfsc.co.uk/files/Safety%20Briefings%20_%20Presentations/Flight%20Ops%20-%20Stall%20recovery%20Presentation%20Airbus%20June%202010.pd f) and the procedures as coppied from FCTM A330/A340 (think it´s from Cathay Pacific) from 2006. I admit, i dont know wether those procedures underwent a further change between 2006 and AF447 loss.

Bolding by me
FCTM A330/A340
Non-normal Operations 8.20.15
Operating Techniques REV 2 (25 JUL 06)

STALL RECOVERY
In alternate and direct laws, an aural stall warning “STALL, STALL, STALL” sounds at low speeds. Recovery is conventional. Apply the following actions simultaneously:

· Set TOGA thrust
· Reduce pitch attitude to 10° below FL200 or 5° at or above FL200
· Roll wings level
· Check that the speedbrake is retracted
Below FL200 and in the clean configuration, select Flaps 1. If ground contact is possible, reduce pitch attitude no more than necessary to allow airspeed to
increase. After the initial recovery, maintain speed close to VSW until it is safe to accelerate. When out of the stall condition and no threat of ground contact exists, select the landing gear up. Recover to normal speeds and select flaps as required. In case of one engine inoperative use thrust and rudder with care.

The aural stall warning may also sound at high altitude, where it warns that the aircraft is approaching the angle of attack for the onset of buffet. To recover, relax the back pressure on the sidestick and if necessary reduce bank angle. Once the stall warning stops, back pressure may be increased again, if necessary, to get back on the planned trajectory.


Again bolding by me to highlight some points.
First the old procedure is not named stall approach recovery, but stall recovery. It deals with the situation AF447 was in, alternate law. The actions should be applied simultaneously. Set TOGA thrust. Reduce pitch to 5° above FL200.

That is quite a difference to the new wording

– Apply nose down pitch order on the side-stick
– If needed, reduce thrust in case of lack of pitch down authority
– Ensure wings are level

because a reduction of pitch can be achieved by a reduction in NU force or, if pitch would be less than 5° and PF is focused on the number 5° pitch, he may be motivated to increase pitch to 5°.

The last para is interesting too. It disqualifies the stall warning at high altitude to being just the point of buffet onset (not being stalled already, which might well happened). Again here "relax pressure on SS, no word of ND input. And further on ..... "once stall warning stops, back pressure may be increased again....... not reapplied again.


And the summary of the new procedure says it all (bolding by me)

• Spirit of what is the new procedure
 One single procedure to cover ALL stall conditions
 Get rid of TOGA as first action
 Focus on AoA reduction

If the PF judged the first spurios stall warning at the beginning of the climb as not valid, but the second one at FL375 as valid, then he acted in accordance with the old stall recovery procedure described above by
-applying TOGA and simultaneously reduce backpressure on SS, which for sure was not enough, because a full ND input would have been appropriate. But where do you find a ND input in the procedure of 2009?

By the way, it has to be emphasized that those procedures (the old and the new one) are derived from thinktanks originating from A+B.

I dont think i would have followed this old procedure if trapped in this situation, because my expierience would have hopefully overridden this "nonsense procedure. But did the PF ever expierienced a real stall in a jet?

Mr Optimistic
26th Jul 2011, 17:43
But if a stall wasn't recognised, why should stall recovery training be relevant ? Ditto THS authority in the absence of sustained ND commands. Mind you, it would be reassuring if they did train it properly in any case, would seem a pity to spend money training and to cock it up. AS SLF I am surprised that with all the instruments and automation to help, it was possible for 3 experienced and trained crew not to be made aware through appropriate indications and prioritised warnings that the a/c had stalled. Of course leaving the stall warner activated when off the ground might have helped, though in this case even that could be doubted.

takata
26th Jul 2011, 17:54
There seem to be a lot of different stall recovery procedures on the market from the time before AF447.
But only one relevant at the time of AF447 is what I already posted above from Air France A330 2009 FCOM (Rev.24).
Anyway, I don't understand how one may consider that PF actions at this second stall warning (which lasted 50+ seconds) could match any published stall procedure at all without completely twisting the facts. Neither TOGA nor sustained pull-up would be part of it.

Lonewolf_50
26th Jul 2011, 18:03
Recency of training.

What stall warning response maneuvers were last practicied by either pilot in the cockpit during their last simulator training session?

This is a human factors issue that I've seen raised in more than one aircraft mishap investigation, including one I was personally involved with.

RetiredF4
26th Jul 2011, 18:41
Takata
But only one relevant at the time of AF447 is what I already posted above from Air France A330 2009 FCOM (Rev.24).

Is there also a FCTM from Air France available with the relevant paragraph like that one posted by myself?


Anyway, I don't understand how one may consider that PF actions at this second stall warning (which lasted 50+ seconds) could match any published stall procedure at all without completely twisting the facts. Neither TOGA nor sustained pull-up would be part of it.

Isn´t the new generation of pilots focused on procedures and SOP´s and a strict obedience of those procedures, whereas my generation was challenging those procedures and their application dependent on the relevant situation and based on their own experience (and improving those by doing so)?

And based on that statement (also it has a ? at the end) and the old stall recovery procedure (not stall procedure, you misnamed probably) the actions of AF447 reflects the application of this procedure to detail, without twisting any facts. We might not understand, why they continued the aplication of this non functioning procedure for so long, but again, see above.

It would be a better approach to question the implementation of the old procedure instead of twisting the application on behalf of the wrong outcome.

Lonewolf_50
26th Jul 2011, 18:58
retired F4: spot on, and not to mention the training norms and experiences for that particular procedure and situation.

Getting at that may shed some light, but it may also be difficult to do. Fear of blame seems to be infesting corporate culture.

RetiredF4
26th Jul 2011, 19:17
That there is a big problem is recognized by the industry

See flightsafety.org from apr 2011 (http://flightsafety.org/asw/apr11/asw_apr11_p46-49.pdf)

The more i´m wondering, why we tend to disregard or to deny this problem on the expert level.

Zorin_75
26th Jul 2011, 19:26
the actions of AF447 reflects the application of this procedure to detail, without twisting any facts.

Hmm. In which way does maintaining nose-up inputs until pitch attitude ends up at 16° reflect "Reduce pitch attitude to (...) 5° at or above FL200"?

bearfoil
26th Jul 2011, 19:33
Approach this accident as if the Pilots were not stupid, and Franz starts to make perfect sense. (Probably not just to me!)

RetiredF4
26th Jul 2011, 19:35
Quote:
Originally Posted by RetiredF4
the actions of AF447 reflects the application of this procedure to detail, without twisting any facts.

Zorin_75 Hmm. In which way does maintaining nose-up inputs until pitch attitude ends up at 16° reflect "Reduce pitch attitude to (...) 5° at or above FL200"?

It does not at all, and we should ask the question how come?
Maybe that is the reason?

The aural stall warning may also sound at high altitude, where it warns that the aircraft is approaching the angle of attack for the onset of buffet. To recover, relax the back pressure on the sidestick and if necessary reduce bank angle. Once the stall warning stops, back pressure may be increased again, if necessary, to get back on the planned trajectory.

Together with
- lack of training in manual flying,
- lack of training in flying in this altitude ,
- lack of training in manual flying in this altitude in alternate law

continue with

- at night
- in WX /maybe turbulence
- without airspeed indication
- sudden stress

and you might find lots of reasons, why this recovery attempt with a meanwhile outdated procedure failed.

Mr Optimistic
26th Jul 2011, 19:37
So you think they knew they were stalled ?

bearfoil
26th Jul 2011, 19:41
If they were unaware of Stall, they would select TOGA exactly, why?

RetiredF4
26th Jul 2011, 19:51
Mr. optimistic
So you think they knew they were stalled ?

I stated that before already. They recognized the first intermittent stall warning as a valid indication due to applying too much NU input (like pulling the A/C into the stall warning AOA) at begin of climb and reacted with ND input (reducing the climb rate to 700 fpm). There was too much NU SS input after the disengagement of AP+Athr due to inexpierience and lack of training, the reaction of the aircraft with the amount of pitch was a surprise. The correction with ND input was not big enough (PX comfort, not to want overreact again,...)

The second stall warning was honored with the stall recovery procedure by applying TOGA thrust, however pitch reduction was again either not applied correctly or not applied enough or other reasons (cant think of any though besides of thrust, which i myself cant qualify, although it is of concern in oficial airbus publications dealing with new stall recovery procedure) caused the pitch to increase to 16°.

What else than a reaction to the stall warning should have motivated the crew to apply TOGA thrust?

Mr Optimistic
26th Jul 2011, 20:09
'What else then a reaction to the stall warning should have motivated the crew to apply TOGA thrust?'

'If they were unaware of Stall, they would select TOGA exactly, why?'

I am not convinced they knew/thought/suspected they were continuously stalled. Perhaps belief in the reliability of the messages and warnings left them and in a fog of doubt they tried to 'climb out'. Nose up and lots of thrust. What was in their minds ...structural anomaly, inexpliable control faults, heavy icing...we don't know, but.......

Edit: 'We have no valid indications...' was it ? Not we are still stalled or try this, that or the other. Yes I know the CVR was heavily parsed but without use of the word 'stall' I think the first question is did they know, and perhaps the second may be, knowing that why did they...........

RetiredF4
26th Jul 2011, 20:17
Mr Optimistic
I am not convinced they knew/thought/suspected they were continuously stalled. Perhaps belief in the reliability of the messages and warnings left them and in a fog of doubt they tried to 'climb out'. Nose up and lots of thrust.

I would consider this as an option, if they wouldn´t have talked about the unavailability of a higher FL due to OAT just some minute before. And without AP and Athr the aircraft is easier to fly in lower FL than at max possible FL.

It´s one of the first lessons learned with TS and buildups: Don´t try to outclimb one, it might rise faster than your machine is able to climb. Aditionally, there was no danger from below or from the FL they where flying at, which would have disappeared when flying 2000 feet higher. At least i dont know one.

An intentional climb is a "no option" for my thinking.

RetiredF4
26th Jul 2011, 20:38
Also this (http://www.ukfsc.co.uk/files/Safety%20Briefings%20_%20Presentations/Airbus%20Safety%20First%20Mag%20-January%202011.pdf) was posted before, i think it is appropriate to look at this article again.
Some points out of it:

The value of the AoA SW depends
on the Mach number. At high Mach
number, the AoA SW is set at a
value such that the warning occurs
just before encountering the pitch
up effect and the buffeting.

Typically, in cruise at high Mach
number and high altitude, at or
close to the maximum recommended FL, there is a small margin between the actual cruise AoA
and the AoA STALL. Hence, in
ALTERNATE or DIRECT LAW,
the margin with the AoA SW is
even smaller

Equally, in similar high FL cruise
conditions, in particular at turbulence
speed, if the pilot makes significant
longitudinal inputs, it is not unlikely
that it reaches the AoA SW value.

For those reasons, when in ALTERNATE or DIRECT LAW, it is recommended to fly at a cruise flight
level lower than the maximum recommended. A 4,000 ft margin is to
be considered. Then, for the same
cruise Mach number, the IAS will
be higher, the AoA will be lower,
and therefore the AoA margin
towards AoA SW will be significantly increased.

A practical exercise done in flight
in DIRECT LAW on an A340-600
and well reproduced in the simulator consists in performing a low altitude level flight deceleration at idle
until the SW is triggered, and then to
push the THR levers to TOGA while
continuing to pull on the stick in order to maintain the altitude.
The results of such a manoeuvre
are:
q In clean configuration, even if
the pilot reacts immediately to the
SW by commanding TOGA, when
the thrust actually reaches TOGA
(20 seconds later), the aircraft
stalls.

This shows that increasing the
thrust at the SW in order to increase
the speed and hence to decrease the
AOA is not the proper reaction in
many cases (this will be developed
in the following chapter).

In addition, it is to be noticed that,
at high altitude, the effect of the
thrust increase on the speed rise is
very slow, so that the phenomenom
described above for the clean configuration is exacerbated.
Obviously, such a procedure leads
to potentially unrecoverable situations if it is applied once the aircraft has reached the aerodynamic
stall (see next chapter).

Even if the traditional procedure
can work in certain conditions if
the pilot reacts immediately to the
SW, or if he is not too adamant on
keeping the altitude, the major issue comes from the fact that once
the Stall Warning threshold has
been crossed, it is difficult to know
if the aircraft is still approaching to
stall or already stalled. Difference
between an approach to stall and an
actual stall is not easy to determine,
even for specialists.

The AoA decrease may be obtained
indirectly by increasing the speed,
but adding thrust in order to increase
the speed leads to an initial adverse
longitudinal effect, which trends to
increase further the AoA (fig. 4).
It is important to know that if such
a thrust increase was applied when
the aircraft is already stalled, the
longitudinal effect would bring the
aircraft further into the stall, to a
situation possibly unrecoverable


Well, enough said from my point of view, i´ll go back to my armchair, hope i didn´t produce too much garbage.

Mr Optimistic
26th Jul 2011, 20:41
Yes, I see that. As SLF who am I to know, however climb is exactly what they did in the first instance and subsequently they were faced with rapidly unwinding height by which time their previous height limit was a fading memory. Two possiblities then, they were stalled, knew it and didn't begin to start a plausible recovery owing to what.....bad training/inappropriate SOP's, bad execution or second, didn't get the diagnosis right and were then flummoxed ? Had the Captain got all the facts when he returned (about which there is doubt) perhaps he could have illuminated the fog. If (biggish if I grant you), even he couldn't get at least a timely start to a stall recovery going isn't the simplest explanation that they didn't realise they were stalled ?

Sorry, just saw the subsequent post !

TioPablo
26th Jul 2011, 23:53
Greetings,

I keep asking myself (slegde hammer)... Why don´t we wait till friday or even more... Read what the ppl involved in this investigation have to say? We haven´t that much data so far... Neither did those involved ever sinds 2009 till now...
I hope you stop fighting each other, coz the goal is to solve the problem... Nothing else. You will contribute to that goal (and you already did without notice), by thinking toghether, not the other way around...

averow
27th Jul 2011, 00:49
If I may briefly chime in and then return to lurking: In my own profession of medicine we strongly encourage students to challenge old dogmas and procedures; in so doing they really can wrap their heads around why "the rules" evolved the way they did. More often than not, in surgery/aviation lessons learned are hard won, and sometimes fatally so. Rules of thumb can help when one is overwhelmed with sensory input from sophisticated technology.

As time goes on, and our understanding of deeper mechanisms evolves, so can our hard learned drills and emergency procedures. IMHO this needs to happen slowly and cautiously with attention to what has been learned in the past.

bearfoil
27th Jul 2011, 21:07
Hello averow.

Unfortunately, all too often the attention paid to sincere questions is directly proportional to the standing of the questioner.

To the extent that this is not so, your post is compelling. Surgery especially has a relationship to your sentiments; for a long standing aviation protocol has been given some attention in the last few years. Briefly, the Operating room is starting to be understood as a sort of flight deck, where decisions and actions are critical, and time sensitive, to put it mildly. Two concepts are assigned a new perspective: CRM, and Lists.

Cockpit Resource Management, and the checklist. Perhaps a PM, I was recently deleted for mentioning an object that I assume is available at some price.

stepwilk
27th Jul 2011, 22:50
As I'm sure you both know, Dr. (and writer) Atul Gawande's work has been important in this regard.

ilesmark
28th Jul 2011, 11:24
Press release 25 July 2011 (http://www.bea.aero/en/enquetes/flight.af.447/pressrelease25july2011.en.php)

jcjeant
28th Jul 2011, 13:13
Hi,

In a simulator test .. the plane was recoverable ....
Press "France Infos" (french)

Pour France Info, notre spécialiste aéronautique, Frédéric Béniada, a pu lors d’une séance en simulateur de vol, revivre minute par minute le scénario de la catastrophe. Il nous livre ses conclusions.

Vol Rio-Paris : la catastrophe reconstituée dans un simulateur de vol - international - toute l'actualité internationale - France Info (http://www.france-info.com/monde-ameriques-2011-07-28-vol-rio-paris-la-catastrophe-reconstituee-dans-un-simulateur-de-vol-553146-14-16.html)

ilesmark
28th Jul 2011, 13:32
Is there an English version of this anywhere??

ChristiaanJ
28th Jul 2011, 13:41
Hi,
In a simulator test .. the plane was recoverable ....
Press "France Infos" (french)
No. The author (pilot?) states clearly they succeeded in recovering the simulator from the 'stall' because they knew exactly what was happening. He does not say tne plane was recoverable in reality.

And we've already been through the difference between the simulator and the plane in that part of the flight envelope.

jcjeant
28th Jul 2011, 15:10
Hi;

No. The author (pilot?) states clearly they succeeded in recovering the simulator from the 'stall' because they knew exactly what was happening. He does not say tne plane was recoverable in reality.
That's a interesting statement
How does the pilots "in reality" don't know they are in a stalling aircraft ?
Airbus instruments and systems are wrong to the point to not show valuables indications to the pilots ?
Are the Airbus simulators better than the real thing ?
The pilots in the simulators were able to see they were in a stalling aircraft .. why not the AF pilots ?
The conclusion anyways reality or not is a good point for Airbus ....

Jet Jockey A4
28th Jul 2011, 16:01
I listened to the conversation and to me it is not clear what they are getting to... A lot of talking but no clear answers.

The one theme that does come back a lot is the relationship or interface between aircraft and humans and how Airbus may have to rethink it big time.

It seems the two pilots perhaps three when the captain comes back into the cockpit didn't know what was going on or what was wrong. They were confused and did not know how to solve the problem(s) and how to apply a solution to get them out of it.

At one point they say the aircraft stalled but then say the systems worked because the Airbus cannot stall? Apparently they had access to the cockpit transcripts because they say you can hear the "Stall warning" and that there was no panic in the cockpit all was calm and professional.

They claim from their test in the sim that the crew had about only 40 seconds to figure out and save the aircraft that after that they were going to go for a ride until it crashed.

Not being an Airbus pilot I am totally shocked that these pilots did not know they were in a high altitude stall scenario and could not just apply common sense and fly the aircraft out of it.

What is it with the Airbus that a pilot cannot just push the nose over to a 5 degree nose down and apply MCT and fly out of this stall?

BTW, one of their so called aeronautic experts is a pilot but there is no mention of his background/experience or what type of license he holds and if he is typed on any aircraft in the conversation. The other is or was at one point an Airbus 330 pilot but that's all we know.

I guess it would be prudent to take what is said in this conversation with a grain of salt because there are a lot of unknowns.

Best wait for the July 29th report from BEA.

ChristiaanJ
28th Jul 2011, 17:23
BTW, one of their so called aeronautic experts is a pilot but there is no mention of his background/experience or what type of license he holds and if he is typed on any aircraft in the conversation. The other is or was at one point an Airbus 330 pilot but that's all we know.
I guess it would be prudent to take what is said in this conversation with a grain of salt because there are a lot of unknowns.

Beniada is an aviation journalist, with a quite nice photo book about Concorde to his credit. His competence and experience as a pilot is unknown.

Feldzer did fly as an Airbus captain... then became director of the Le Bourget museum. Now retired, and mostly known as a "talking head"/"expert" the moment French TV needs one.
He's the one that came up with the moronic idea of starting up the engines of one of the French museum Concordes.... which should give you an idea of his "technical competence".

AlphaZuluRomeo
28th Jul 2011, 21:41
france info (http://www.france-info.com/monde-ameriques-2011-07-28-vol-rio-paris-la-catastrophe-reconstituee-dans-un-simulateur-de-vol-553146-14-16.html)
[...]
Also a desire to 'protect' the Airbus technology to the public eyes ... ?

"The airplane did not stall, il s'est enfoncé (it has gone deep ?), thanks to the protections."
"The protections have been effective but not understood by the pilots."
Well, on that you could call Mr Feldzer a liar, plain & simple :
- the aircraft did stall
- most of the protections were inop (ALT LAW + rejected ADRs)

However, I think it's more a -very poorly phrased- attempt of vulgarization. Which by the way will indeed somehow "protect" the aircraft maker reputation, for sure.
In french, "décrocher" (to stall) may be heard as a "violent" phenomenon to the general public. OTOH "s'enfoncer" (to sink) is a "softer" thing... and may be more "meaningful" to an uneducated ear (no offense).
And protections seem to stand for some flight laws/FBW features, here (i.e. maintaining pitch when stick is released and/or maintaining 1g)... Bad phrasing again, using a precise, technically meaningful word in an "oblique" sense.

I listened to the entire interview (thanks for the link) and did not learn much (if not nothing). It is clearly intended for the "general public", hence my interpretation above. Too bad one doesn't think it's worth to explain correctly... I'm sure it's possible, with a little (more?) goodwill.

------

@ jcjeant : "The pilots in the simulators were able to see they were in a stalling aircraft .. why not the AF pilots ?"
That's not what is said. It is said they (those who take a sim tour) were able to recover because they knew what was going on. Not because they [B]saw it [from the instruments].
(my comments between [brackets])
I think your other (previous) questions were purely rethorical ones, and don't call for an answer. :)

jcjeant
28th Jul 2011, 21:55
Hi,

The press again ....
They tell they had access to parts of the BEA report to be published in few hours..
AF*447*: le rapport d'enquête met en cause l'équipage* - Yahoo! Actualités (http://fr.news.yahoo.com/af-447-rapport-denqu%C3%AAte-met-cause-l%C3%A9quipage-175600793.html)
I read that the less experimented pilot was the PF ..
I read also that this crew had not have adequate training for the situation encountered by AF447 (loss of speed indications)
Read also that all commands of the pilot were perfectly executed by the plane system
And also read that never the crew know they were in a stall situation
Again and again all fingers are pointing to the lack of training of the pilots and some errors made in the event.
And immediate reaction of a AF union (Alter)
Les accusations contre les pilotes du Rio-Paris relancées - Le Point (http://www.lepoint.fr/fil-info-reuters/les-accusations-contre-les-pilotes-du-rio-paris-relancees-28-07-2011-1357523_240.php)
Wait and see ....

ChristiaanJ
28th Jul 2011, 22:23
And immediate reaction of a AF union (Alter)Did you expect anything else from 'Alter' ?

mm43
28th Jul 2011, 22:24
You've got to wonder what goes on at Google Translate when the following is submitted for translation into English and German.
Le Figaro a obtenu, en avant-première, des éléments de l'investigation sur le vol Rio-Paris.The result being:-


The BBC has obtained a preview, elements of the investigation on the flight from Rio to Paris.
Die BBC hat eine Vorschau, Elemente der Untersuchung auf dem Flug von Rio nach Paris erhalten.

Likewise, "metres" was translated in another article into "feet".

bubbers44
28th Jul 2011, 22:31
It seems a lot of people are making last minute statements before the report tomorrow. I agree with most of them because we have been saying that for months. Saying, I told you so, tomorrow, isn't much help right now.

Tomorrow, hopefully, we will get a meaningful report then we can talk about it with some facts.

lomapaseo
28th Jul 2011, 23:21
Tomorrow, hopefully, we will get a meaningful report then we can talk about it with some facts.

and before the end of the day the talk will extend way beyond the facts

xcitation
29th Jul 2011, 00:03
Again and again all fingers are pointing to the lack of training of the pilots and some errors made in the event.
Wait and see ....

Clearly a very confusing and over burdened situation for PF. 40 second window to understand situation and recover is tight given the known facts.
For me the big question is why they chose the general nose up stick input with aparently PFD showing pitch already at +16 deg and a/s below Vs. Was the final hole to line up in the swiss cheese the stall alarm inhibited at <60kts?

bubbers44
29th Jul 2011, 01:57
Yes, that is how it was done.

RWA
29th Jul 2011, 02:32
Well, I guess this is all the extra information we are going to get. 'The aeroplane behaved perfectly, the pilots just stuffed up (now including the captain)........' etc. etc.

My French is well over fifty years old, like the rest of me, so I had to depend on 'Google-translate' for the main text. But I'll offer a personal translation for the title - colloquially speaking, "AF 447 : les pilotes en ligne de mire" probably translates best as "AF447 : the pilots to cop the s**t."


"The BEA will present a new report Friday. The crew would be called into question, according to Le Figaro.

The third report by the BEA on the exact circumstances of the accident flight Rio-Paris is expected and feared. The aim is to shed light on the main stages of the disaster that led the Flight 447 to disappear on 1 June 2009 with 228 people on board. Even before its publication on Friday at 14h, the pilots' unions are on the frontlines to expose their responsibilities would be allocated by the Office of inquiry and analysis.

The crew never realized that the aircraft had stalled

According to The Figaro.fr, the report released Friday is mainly because the crew. The BEA will provide Friday on "new facts derived from the exploitation of data from flight recorders." And, according to Le Figaro, "the crew never realized that the aircraft had stalled and has never applied the appropriate maneuvers." "When the captain, who had gone to rest, came back in the cockpit, his two colleagues told him about technical problems but have never talked about dropping out, provides a framework for Air France on a daily basis. Commander edge has never been able to save the situation. "

"Fragmented elements and gearboxes," says the BEA

Even before the report, the BEA has responded, saying "these elements were fragmented and gear." "It's certainly not accusing the crew as it made it mean that we have the chain of causes and Friday, the BEA will say," we understood everything we needed to that the accident does not happen again, "said a spokesman for the BEA, the investigating technique.

The BEA had presented the film in late May of last moments of flight with an initial analysis of black boxes rescued. This first study had pointed to the failure of the Pitot probes, depriving the pilots of the velocity measurements of the device. But investigators have always felt that this could not explain alone the accident.

The union Alter advance another hypothesis about the causes of the accident: a failure of the flight computers manufactured by Airbus. "One wonders, after analysis, if not the flight computers that brought the plane to stall," said William Pollard."


AF 447 : les pilotes en ligne de mire - Europe1.fr - France (http://www.europe1.fr/France/AF-447-les-pilotes-en-ligne-de-mire-647819/)

RobertS975
29th Jul 2011, 03:21
One point of confusion in the cockpit can be attributed to the fact that the stall warning ceases to warn below 60 kts. There is evidence that the pilot at the controls at one point pushed the stick forward to lower the nose, and when the plane accelerated to over 60 kts, the stall warning started up again.

bearfoil
29th Jul 2011, 03:36
Which particular 60knots are we addressing? Indicated, or TAS? Time?

RWA
29th Jul 2011, 04:03
I'd have thought that there are at least two occasions, bearfoil - both IAS:-

1. the initial upset at the top of the 'zoom climb' - warning sounds, pilot applies TO/GA power, warning stops.

2. The attempted recovery (to quote the BEA 'note'):-



"At 2 h 12 min 02, the PF said "I don’t have any more indications", and the PNF said "we have no valid indications". At that moment, the thrust levers were in the IDLE detent and the engines’ N1’s were at 55%. Around fifteen seconds later, the PF made pitch-down inputs. In the following moments, the angle of attack decreased, the speeds became valid again and the stall warning sounded again."

For all we know, that led the pilot(s) to try the TO/GA thing all over again?

In that connection, just noticed something else; the next entry in the 'note' is timed one minute and thirty seconds LATER than the one I just quoted - but the BEA tells us nothing at all about what happened during that period:-


"At 2 h 13 min 32, the PF said "we’re going to arrive at level one hundred"."

Leading to the conclusion that the attempted recovery was made MUCH higher than I, at any rate, have been thinking up to now?

As a minimum, let's hope that the BEA publishes a full CVR transcript,'fills all the gaps' in the narrative, and above all explains not only why the THS went to 'full up' in the first place; but also why, more important, it stayed at full up even though the pilot had begun making nosedown inputs.

If they don't, IMO it'll be clear evidence that a cover-up on the grand scale is in progress.

gbour
29th Jul 2011, 05:13
This has not yet hit the English speaking media. From Die Welt: Airbus chief pilot Ferando Alonso (sic) critizises the AF crew for not applying proper procedure by inducing a climb twice as steep as indicated and failing to react to the stall warning for 50 seconds.

German speakers:
Air-France-Absturz: Crew von Todesflug AF 447 missachtete Flugregeln - Nachrichten Panorama - Weltgeschehen - WELT ONLINE (http://www.welt.de/vermischtes/weltgeschehen/article13513846/Crew-von-Todesflug-AF-447-missachtete-Flugregeln.html)

Avionista
29th Jul 2011, 10:11
Looks like pilot error!

Google translation of "Le Figaro" leak:

The night of 31 May to 1 June 2009, the captain left the cockpit to 2:01 to go to rest and is replaced by a co-pilot takes his place on the left. When the Pitot probes frosting and the autopilot disconnects 2:10, the configuration of the crew is as follows. The captain is out of the cockpit, what is allowed during a flight "enhanced" (with three drivers). The less experienced co-pilot, who sits on the right is "driver based": it gets the control of the aircraft. The second co-pilot (Pilot Officer reinforcement) seated on the left is "driver not on" his mission is to manage failures and to provide information to his colleague.

Just after the autopilot disconnect, the pilot on the right gives a first-rate nose-which raises the unit up to 37,500 feet. At this altitude, the risk of dropping out, that is to say the loss of lift of the aircraft and so his fall is very important. The pilot should never have to mount the unit at that altitude. It seems that at this moment, "the event Pitot" is completed. The device found consistent speeds and just then the pilot to manually maintain the trajectory and the altitude of the aircraft to avoid the accident that follows. The loss of information anemometer was only temporary.

"My colleague had to panic"
The co-pilot seated on the left loses precious seconds to call the captain who is out of position. It activates an alarm located on top of his head and loses sight of the display failure. He does not see his colleague maintains an order to pitch, that is to say, continues to pull the handle, the opposite of what to do. This action is out of the plane's flight envelope: it picks up and drops into the ocean.

"This maneuver is totally incomprehensible, said an Air France pilot. My colleague had to panic. "During the fall of the device, the first officer maintains his order to pitch despite a few trials in the other direction, exacerbating the situation and prevent the aircraft to find the lift. The procedure in force at that time at Air France said to the throttle and reduce the incidence, that is to say, to push the handle. The co-pilot put the throttle but runs the opposite of what to do with the handle despite the impact of an alarm "Stall" stall for almost a minute.

When the captain entered the cockpit, neither pilot talks stall him. They tell him about technical problems and tell him they do not understand. The captain is unable to analyze the situation and help his two colleagues. Seconds before impact, the pilot takes the controls on the left. But it's too late, he can not do anything.

"This scenario raises the question of the level of the crew, says one expert. Either it was a bad crew and we need to understand how this could be possible for Air France, its level was compared to other standard crew of the company and so is the training and recruitment that will be questioned . 'In the pilot, we are reminded that certain formations, especially the control in icing conditions at high altitudes, came after the 447 despite twelve reported incidents of Pitot probes in-house.

chrisN
29th Jul 2011, 10:12
RWA’s translation included: "Fragmented elements and gearboxes," says the BEA

Could this be a mistranslation which should be “transmission”? I don’t see how “gearbox” makes sense in this context.

“Transmission” is used in engineering for gearboxes etc., but the word is also used in some contexts for human/human communication.


"Fragmented elements and communications" would make more sense to me.

AlphaZuluRomeo
29th Jul 2011, 10:32
Yes, it is a mistranslation.
No, it shouldn't be "transmission".

"réducteur" is the word. Translated as a noun (gearbox) by Google, it's in fact an adjective (in this case), meaning the leaks reduce the amount of sense the BEA put on the accident.
I'm not confident enough on my english skills, but perhaps 'reductive' or 'reductionist view' should do?

The BEA is saying it's too simple (and unrepresentative) to (just) say "pilot error, and that's all folks" (which is ~ what the mass media are doing, they don't want a complex answer, it has to be the plane's fault, or the crew's fault, but keep it simple for underbrains, please).

AlphaZuluRomeo
29th Jul 2011, 10:40
The BEA just published a "Synthesis note" and "Safety recommendations":
FR : Vol AF 447 (http://www.bea.aero/fr/enquetes/vol.af.447/vol.af.447.php)
EN : FLIGHT AF 447 (http://www.bea.aero/en/enquetes/flight.af.447/flight.af.447.php)

BOAC
29th Jul 2011, 10:49
Oh dear.:{

SaturnV
29th Jul 2011, 10:57
Is there more to be released later today?

The synthesis note is 4 pages in both French and English, and the set of recommendations is one page.

RWA
29th Jul 2011, 11:02
Quoting ChrisN:-

RWA’s translation included: "Fragmented elements and gearboxes," says the BEA

Blame google mate - the only translation I'll take responsibility for is the title of the article! :)

Avionista, as far as I know the BEA didn't say which pilot was sitting in which seat. I've been assuming that the normal setup - senior F/O in his accustomed (righthand) seat - applied, and further that the junior one was in the lefthand one, and also the PF. That's supported by the captain's words on leaving the flightdeck ("He's taking my place.") The point coulde be important since I understand that the standby instruments on an A330 are in a 'left of centre' position on the A330 panel - so if the main instruments were misbehaving it would have been difficult for the more senior F/O to take over, he'd have had to lean way over to his left.

Typical of the BEA on this occasion, though - they didn't provide even the simplest and least controversial information (like which pilot was flying the aeroplane) in their report.

Quoting Avionista quoting Le Figaro:-


Just after the autopilot disconnect, the pilot on the right gives a first-rate nose-which raises the unit up to 37,500 feet.


In fairness to the PF (whichever one it was) I have to remind everyone that the only 'nose-up input' he applied at the onset of the accident was immediately after the sign-off. The BEA states that the 'zoom climb' started at least 11 seconds after that - and there is no mention of the PF moving the stick either way until he applies 'nose-down' to (successfully) counteract the climb.

That strongly implies that the PF did not cause the climb - unless the A330 takes 11 seconds-plus to respond to control movements?

In any case, flying manually, on instruments, in rough weather, one would expect that there'd have been literally dozens of control movements over the period of the whole event. But the BEA chooses to mention only three or four of them?

I only hope (without much hope) that this third 'interim report' gives us a lot more 'hard information.' For a start, the BEA must already know everything that the CVR and the FDR recorded? Be interesting to see how much more they decide to tell us? Maybe 'third time lucky'.........?

PS, thanks - SaturnV must admit that I rather expected as much (or, rather, 'as little').

One immediate contradiction 'jumps out' at you:-



At 2 h 13 min 32, the PF said "we’re going to arrive at level one hundred". About fifteen seconds later, simultaneous inputs by both pilots on the sidesticks were recorded and the PF said "go ahead you have the controls". The angle of attack, when it was valid, always remained above 35 degrees.

"• Throughout the flight, the movements of the elevator and the THS were consistent with the pilot’s inputs.



If we are encouraged to believe that the THS reacted to 'noseup inputs' by pitching up, why did it not in turn respond to 'nosedown inputs' by pitching down?

SaturnV
29th Jul 2011, 11:22
RWA, there may be more later. There is a press conference at 14:30.

Jet Jockey A4
29th Jul 2011, 12:04
Oh dear x 2. :{:{

I do not fly or know how the systems work on the Airbus aircrafts.

I do not know if we have all the details yet.

I do not know if there is a cover up here (for those who may believe in that theory).

In any case if the information given so far is correct it is hard to believe a competent crew with experience on type would allow this aircraft to go from FL350 to FL380, stall the aircraft and never recover because they did not understand what was happening.

What even happened to flying the attitude and using power when all other things fail?

Someone with Airbus experience tell me this...

They still had 3 ADIs or artificial horizons available to them, no?

They still had full control over the inputs to the flight controls and engines, no?

The left PFD lost the airspeed for 29 seconds, the ISIS for 54 seconds so what about the right hand PFD airspeed indicator?
Does the #2 PFD airspeed source come from the same source as the ISIS?

Anyhow even if all 3 airspeeds were out for a limited amount of time how does that figure into not being able to remain at FL350 and not zoom climb at a very high rate (7000/min) to FL380?

If all fails with the airspeed (and TAS) you could always back yourself up with ground speed for a rough estimate. If an aircraft wants to climb when it is supposed to be level at a certain altitude, counter act the climb by nose down input. In most aircrafts when you disconnect the AP, one usually finds it is not "properly trimmed" and manual inputs are required. Is this not the case in the Airbus?

Maybe I'm missing something here because this happened in an Airbus but it is hard to believe that some frozen pitot tubes which were the originating factor in this tragedy confused the pilots to the point of no recovery.

From my point of view it sure seems like the crew messed it up and allowed an aircraft to stall at high altitude and never recovered it.

DozyWannabe
29th Jul 2011, 12:29
Well, I guess this is all the extra information we are going to get. 'The aeroplane behaved perfectly, the pilots just stuffed up (now including the captain)........' etc. etc.

I don't know how a request for addition of an AoA indicator, as well as numerous additions to flight recorder parameters indicates that the BEA considered the aircraft "perfect".

Hopefully the interim report proper will be published after today's press conference, but it looks to me like what the BEA are saying is that while it appears that the crash was in part caused by a mishandling of the aircraft in the wake of a UAS incident, exacerbated by night IMC and unsettled weather, it also suggests that the pilots did not receive proper training in either manual aircraft handling at high speed and high level flight, CRM training in how to operate and communicate on the flight deck when the captain is on his rest period, and that the aircraft itself presents information that could be perceived as confusing when outside of its flight envelope. In short, there's room for improvement at both AF and Airbus (and I suspect the industry in general).

[EDIT : Note that my info comes from the "Synthesis" and Recommendations published this morning, which may not have been available when you posted. If anything I think that highlights the importance of taking any press-filtered information with the requisite shovelful of salt.]

sebaska
29th Jul 2011, 12:33
RWA
If we are encouraged to believe that the THS reacted to 'noseup inputs' by pitching up, why did it not in turn respond to 'nosedown inputs' by pitching down?

It was explained to you already, yet you choose to ignore that and champion your pet theory of "cover up". :ugh:

jcjeant
29th Jul 2011, 14:13
Hi,

In any case if the information given so far is correct it is hard to believe a competent crew with experience on type would allow this aircraft to go from FL350 to FL380, stall the aircraft and never recover because they did not understand what was happening.If you read the synthesis .. it show that the pilots were incompetents (no training for the AF447 case despite multiple same events in the past)
And also cause no recommendations in the past by the BEA about those events and no a sensed word by DGAC about same events
AF - DGAC - BEA are to put in the same bag and Airbus is not better (they always stated before 2010 that stall training was not needed)

Hopefully the interim report proper will be published after today's press conference,

Maybe you are dreaming ?

before landing check list
29th Jul 2011, 14:21
PILOT ERROR: Air France Jet Plunged Into Ocean Because Pilots Screwed Up (http://www.businessinsider.com/air-france-crash-pilots-2011-7)

I just found this today. I have no idea if it will help or not.

I think you guys can brain storm all you want over the fine points why the computer and or indications did what they did. However the bottom line is either the pilots had mucked up data for whatever reasons and for that reason could not fly the aircraft out of the situation or the freaking system would not let fly the profile what was needed to escape the bad situation.

If we are encouraged to believe that the THS reacted to 'noseup inputs' by pitching up, why did it not in turn respond to 'nosedown inputs' by pitching down? This is not a problem for non FBW aircraft. I say again we are so far ahead of the game we have lapped ourselves and are now behind again.

I will give the pilots the benefit of the doubt on their flying (not managing) skills. I have to ask again, do you want to be able to fly an aircraft or do you want to fly a system? Please do not give me a lame excuse about how fine the system is, just answer the question.

DozyWannabe
29th Jul 2011, 14:24
Airbus is not better (they always stated before 2010 that stall training was not needed)

I think that was a misconception widely held by the industry as a whole, and not specific to Airbus in particular. It certainly looks like AF are going to have to pull their socks up though...

[EDIT : @before landing checl list - I think that's a terribly poorly-summarised article which doesn't even bother to translate what's being said into layman's terms - the whole thing has been reduced to an inaccurate soundbite. ]

jcjeant
29th Jul 2011, 14:28
Hi,

Found on a french site .. the synthesis of the press meeting (in french)


15h04: «Il est nécessaire d'examiner la façon dont est organisée la sécurité des vols chez Air France» affirme le directeur du BEA.
Nouvelle critique sur la coordination dans cette compagnie aérienne.

15h02: L'enquête continue, déclare Jean-Paul Troadec, directeur du BEA. La difficulté réside dans l'analyse du comportement des pilotes, d'où la création d'un «groupe facteur humain».

15h01: Recommandation analogue sur la balise de détresse, qui est un instrument pas très fiable et qui se détruit facilement, dit le directeur du BEA.

15h00: Le directeur du BEA Troadec évoque la difficulté à localiser les épaves d'avion, et émet l'idée de multiplier les données sur les localisations des avions. «il faut réduire au maximum la difficulté de localisation».

14h59: Recommandation sur l'imposition d'enregistrement de nouvelles données

14h58: Recommandation sur les utilisations plus strictes des données des enregistrements de vols.

14h57: Il y a un besoin d'enregistrement des images de la planche de bord, dont le radar, affirme le directeur du BEA.

14h56: Il y a besoin de réaliser une étude sur la présence d'une évaluation d'incidence accessible

14h55: Recommandation sur la suppléance du commandant de bord

14h54: Les recommandations sur l'exploitation, dont le renforcement la compétence des pilotes en pilotage manuel en haute altitude.

14h53: Les recommandations concernent l'exploitation, la certification, les enregistreurs de vols, la transmission des données de vol.

14h52: Il parle de précédentes recommandations, dont les sondes Pitot.

14h50: Le directeur du BEA, Jean-Paul Troadec reprend la parole et ennonce des recommandations de sécurités.

14h50: «Pour essayer de comprendre les actions du pilote; un groupe facteur humain va être créé» dit Alain Bouillard

14h48: Alain Bouillard, du BEA dit que l'équipage et sa formation est conforme (la formation a depuis été modifiée). Il n'y a pas eu de répartition claire des tâches des pilotes. Il pointe les défaillances des pilotes.

14h47: Aucun message de détresse n'a été émis par l'équipage, dit Alain Bouillard du BEA.

14h45: Les pilotes affirment ne plus avoir d'indications valides. Une action à piquer est alors réalisée. L'avion est à 4.000 mètres à 240km/h; L'incidence est toujours à 15°

14h44: Incidence passe à 40°. La chute est 11.000 pieds minute. Les moteurs sont en pleine poussée.

14h43: L'assiette et l'incidence sont à 16°. Les alarmes s'éteignent car les données sont considérées comme invalides.

14h41: Maintien de l'ordre à cabrer du pilote. Les pilotes ne voient pas la situation de décrochage.

14h40: L'assiette progresse au-dessus de 10° et l'avion prend une trajectoire ascendante. L'avion monte, avant de descendre brutalement.

14h38: L'agent commence à détailler les problèmes survenus, dont le givrage des sondes pitot , les alarmes de décrochage qui résonnent, les ordres à cabrer du pilote.

14h35: Récit du début du vol par Alain Bouillard, du BEA. Deux pilotes en cabine. Vitesse normale de croisière. L'agent du BEA retrace les éléments déjà connus du vol d'Air France.

14h33: La conférence de presse du BEA a commencé au Bourget. Le directeur prend la parole, regrettant le traitement médiatique fait sur la catastrophe

ilesmark
29th Jul 2011, 14:30
"Sebaska wrote at #2233 (I don't have the quote facility for some reason)

RWA

Quote: If we are encouraged to believe that the THS reacted to 'noseup inputs' by pitching up, why did it not in turn respond to 'nosedown inputs' by pitching down?

It was explained to you already, yet you choose to ignore that and champion your pet theory of "cover up". :ugh:

"

Where was this explained already, Sebaska? I have looked and I can't see any answer to RWA's point. I think it's a valid one.

bearfoil
29th Jul 2011, 14:33
Without any new evidence, the crash becomes more an exercise in politics, and authority.

Perhaps the bottom line is how much authority (control of evidence) should any entity possess which has a commercial interest in the outcome of their investigation?

DOZY: As a sw boffin, do you expect much of what is needed for an understanding has a particular timeframe?

I think the window around a/p loss, since this is the point at which the vulnerability was highest? If the PILOTS are as described, what is the point in a retrospect of STALL?

How did this START?

jcjeant
29th Jul 2011, 14:34
Hi,

I think that was a misconception widely held by the industry as a whole, and not specific to Airbus in particular. It certainly looks like AF are going to have to pull their socks up though... Well ... the aircraft involved in the crash is an Airbus property of AF and piloted by AF pilots so far I know

jcjeant
29th Jul 2011, 14:54
Hi,

Some comments about extracts of the press meeting:

14h56: Il y a besoin de réaliser une étude sur la présence d'une évaluation d'incidence accessible

2:56 p.m.: There is a need to conduct a study on the presence of an indication of attitude
Those type of instruments are already available ... but were not installed on the AF447

15h02: L'enquête continue, déclare Jean-Paul Troadec, directeur du BEA. La difficulté réside dans l'analyse du comportement des pilotes, d'où la création d'un «groupe facteur humain».

3:02 p.m.: The investigation continues, said Jean-Paul Troadec, director of BEA. The difficulty in analyzing the behavior of pilots, hence the creation of a "group human factor".The analyse of the pilot behaviour is not so difficult .. when you know that the BEA itself show in his synthesis the "lack of proper training" of the AF447 pilots


14h33: La conférence de presse du BEA a commencé au Bourget. Le directeur prend la parole, regrettant le traitement médiatique fait sur la catastrophe

2:33 p.m.: The press conference began in the BEA Bourget. The director speaks, regretting that the media coverage of the disasterFirst at all ... in France the press is free and secondly .. the press articles were based on leaks from the BEA
Before take care of the press .. it's better for BEA to give a look at their personnel !

jcjeant
29th Jul 2011, 15:05
Hi,

Full report available: (so far in french only)
http://media.webcastor.fr/web/bea/f-cp090601e3.pdf

AlphaZuluRomeo
29th Jul 2011, 15:09
jcjeant, take care when translating:

14h56: Il y a besoin de réaliser une étude sur la présence d'une évaluation d'incidence accessible

2:56 p.m.: There is a need to conduct a study on the presence of an indication of angle of attack (not attitude)

:rolleyes:

About the group: question is why the stall alarm was ignored, IMO.

About the leaks: from the BEA ? Sure of that ? Of from interested parties (company, manufacturer, government...) who had access before the general public ?
Do you search for facts, reality, answers ?

xcitation
29th Jul 2011, 15:24
Synthesis Note

Nothing new. A "qui" typo on the english version that should have been caught by the proof readers, a bit sloppy from an organization that is detail focussed, surely a simple spell check would catch it?

Safety Recommendations

Some odd grammer but readable. All looks good addressing the areas of serious concern that we have read in the forum threads. To that extent it is all consistent.
However it still does answer why the pilot inputs of generally nose up which appear to contradict the PFD. Why input stick back when pitch +16 and below Vs with TOGA thrust and N1 near 100%. Perhaps we will never know as we can't see exactly what the flight instruments showed. This appears to be addressed in the remarkable suggestion in the safety recommendations. Is this formally recommending cameras on the flight deck?

Images recorders

One recommends that the regulatory authorities require that aircraft undertaking public transport flights
with passengers be equipped with an image recorder that makes it possible to observe the whole of the
instrument panel. Another recommends defining strict rules relating to the use of such recordings.


Flight parameter recordings

There are two recommendations on recording additional parameters.