AF 447 Thread No. 8 [Archive] - Page 2

gums

28th Apr 2012, 21:38

Thank you, EMIT.

I had an hour and re-read the last interim report and mainly the annotated CVR with system conditions and sensor readouts and.....

I still cry. If was already a ghost ( not there quite there yet), and whispering in those guys' ears, I think I could have helped a lot.

A surprising thing I saw and not focused upon was the bank angles. They re-inforced my initial feeling that the jet was in a really good stall and close to a spin or other completed loss of control. I had previously believed it was more stable in the roll and yaw axis.

And BTW, I flew about 500 hours in the T-33 and we had a climb rate at 35,000 ft of about 1,000 fpm. BFD.

I come back to the basic control laws and the blatant disregard for AoA when airspeed data is deemed unreliable by Hal. So I took my primitive FBW system laws and divided by eight.

- max AoA about 4 degrees
- max gee about 1 or 2 gees

That seemed close enough to fit the 'bus, IMHO.

Our system used the gee input until it hit the AoA limit, then AoA ruled! Our body rates were also in the loop and would come to play if the speed, gee and AoA stuff went FUBAR.

So I look at the traces and annotation and can't understand why the AoA inputs couldn't "limit" or "protect" compared to what I had experienced. So my feeling is that the crew was still locked into the belief that the jet could not be pulled hard enough to stall. And some of the comments seem to indicate this - "we have been trying to climb", and similar.

I then cut the crew some slack and blame the system for the disregard of AoA if weight is off the gear, regardless of the airspeed inputs' validity. AoA rules!! It's something we were taught as clueless yutes when 15 or 16 years old and learning to fly in Cessnas and Luscombes and Aeronicas and....

Further, the warning/advisory systems didn't seem to help.

The "connected" side sticks" argument still has life, but pitch and power still rules, as does some good comm between the folks in the multi-pilot planes. I don't buy all of the side stick complaints, but they do have merit.

As with another contributor here, the final report and recommendations shall be a landmark.

HazelNuts39

28th Apr 2012, 21:45

A33Zab,
Thanks, that answers my question.

They would need dynamic pressure (Vc) and Mach to calculate the rudder deflection correction, so if either of these go NCD the estimated sideslip will also. Maybe that is so, but I don't see it in the trace. Doesn't A33Zab say that in Alt2 it is replaced by Ny without correction?

A33Zab

29th Apr 2012, 00:37

Doesn't A33Zab say that in Alt2 it is replaced by Ny without correction?

Indeed!,and IMO the Ny in ALT2 (Yaw = ALTERNATE YAW LAW) is used for indication of the PFD sideslip indication. (+/- 0.3g max).

The rudder deflection in ALT2 (ALTERNATE YAW) is only a function of pedal and/or Yaw damper input. (based upon the yaw rate).
In ALT2 Yaw damper has a limited authority of +/- 4 degrees in CONFIG 0 (=CLEAN)

D.Lamination

29th Apr 2012, 00:46

Written in layman speak but generally nails the issue. And I say that as an Airbus pilot. Non repeating side sticks and frozen thrust levers have always been a problem along with general lack of physical feedback - a fault first revealed in the Air- Inter A320 prang.
I say to Airbus: spend the $ and buy a few servo motors to make things repeat and move!

View From The Ground

29th Apr 2012, 01:25

"and the jet was state-of-the-art, a type that had never before been involved in a fatal accident."

1994 at Toulouse 7 people died in a take off accident, not commercial flight however still unfortunately a fatal accident. The title of my post says the rest.

Gary Brown

29th Apr 2012, 01:34

D.Laminate wrote:
Written in layman speak but generally nails the issue. And I say that as an Airbus pilot. Non repeating side sticks and frozen thrust levers have always been a problem along with general lack of physical feedback - a fault first revealed in the Air- Inter A320 prang.
I say to Airbus: spend the $ and buy a few servo motors to make things repeat and move! And Boeing pilots of course *always* notice Autothrust disconnects, and the levers moving back to Idle.....

Machinbird

29th Apr 2012, 03:22

The estimated sideslip (elaborated in FCPC) is NOT used in ALT2(& DIRECT) and replaced by Ny rear accelerometer.
Does the Ny rear accelerometer have a fixed mounting position or is there a range of adjustment to zero out lateral g sensing? If adjustable, are there any procedures in setting up this accelerometer that could be non-responsive if the aircraft was in Normal law instead of Alternate law? Is the Ny rear accelerometer used in Normal law?

I realize that this can be potentially be a time consuming area to research, but it might be useful to "sweep out" this corner of the Yaw control system for things that could induce a yaw input in Alternate2 law. FCOM search has been non-productive. TIA :ok:

bubbers44

29th Apr 2012, 05:30

Air France Flight 447: 'Damn it, we’re going to crash’ - Telegraph (http://www.telegraph.co.uk/technology/9231855/Air-France-Flight-447-Damn-it-were-going-to-crash.html)

bubbers44

29th Apr 2012, 06:20

This crash says the pilot not flying needs to be more aggresive in taking over when the other is AFU. A little forward pressure on the side stick would have solved the situation. Most Boeing pilots seeing a control wheel in their gut would do so instantly. Just say I have the airplane and problem is solved. Side sticks make that harder to do. You can not tell what the other pilot is doing from your seat. Airbus isn't going to change anything so I guess noticing the little annunciator is their only clue what the other pilot is doing. Guess this will be happening again.

Owain Glyndwr

29th Apr 2012, 06:56

mm43

29th Apr 2012, 10:27

Originally posted by Owain Glyndwr ...
Philosophically, the yaw damper is a follower and shouldn't be driving the motion unless the system designers really fouled up and produced an unstable system (which they did not).Agreed, and thanks for your generous reply. However, it is somewhat difficult to follow what inputs the YD is getting, and what effect NCD data may be having on the Ny Accelerometer inputs to the YD calculation.

The DFDR Lateral Acceleration (sideslip) trace is reflected in the YD output and its amplitude appears to have increased marginally during the descent and has a natural period of around 7 - 8 seconds which only gets interrupted by prolonged left bank commands. As pointed out earlier, the clockwise heading change is greatest when the Ny driven oscillation is dampened by hard over and held left SS inputs. So my feeling is that the PF managed to dampen the Ny oscillations that could have easily resulted in a total LOC.

Having written the above, then noted your latest comments, I am no further ahead in resolving what I still consider is the YD driving the Rudder and "leading" the Roll/Bank. I've had a look at the Pitch Attitude trace and find that maximum yaw coupled with side-slip tended to occur when pitched up with a RH roll bias.

You say that, "In Alt2 the rudder deflection is controlled by pedal angle and yaw damper commands", and yet in the period we have been looking at, only YD commands have been presented to the rudder. How or why does the Lateral Acceleration trace then synchronize with the YD / Rudder traces? To answer my own question, I have previously posited that the aircraft was effectively 'fish tailing'.:confused:

Its not important to the outcome, though helpful in understanding what is actually happening in what appears on the surface to be an aircraft in a benign stall and retaining some lateral stability, i.e. avoiding the 'spiral dive'.:(

rudderrudderrat

29th Apr 2012, 11:09

Hi mm43,
As pointed out earlier, the clockwise heading change is greatest when the Ny driven oscillation is dampened by hard over and held left SS inputs.
I think the clockwise heading change was due to adverse aileron drag when the wing was stalled. The differential spoilers would have been ineffective in the turbulent flow above the wing. But the RH down going aileron would present more drag to the forward aircraft direction and induce a turn to the right, effectively "the wrong way".

I think that was first explained by Owain.

edit:
So my feeling is that the PF managed to dampen the Ny oscillations that could have easily resulted in a total LOC.
I don't think PF managed to do anything other than mostly pull back during the stall. His roll commands were ineffective once the wing was stalled.

Owain Glyndwr

29th Apr 2012, 11:31

However, it is somewhat difficult to follow what inputs the YD is getting, and what effect NCD data may be having on the Ny Accelerometer inputs to the YD calculation.

The answer to that I think is that there isn't any Ny accelerometer input to the YD calculation when Alt2 is operative. So as as I know, the sole short term input to the YD in this state is rate of yaw. Ny does affect the YD operation when in normal law in that the lateral turbulence damping commands are fed through the YD, and if you want to reduce motion at the back end of the cabin then an accelerometer on the rear bulkhead would be a good starting point but as I understand it this is a pilot selectable option

The DFDR Lateral Acceleration (sideslip) trace is reflected in the YD output and its amplitude appears to have increased marginally during the descent and has a natural period of around 7 - 8 seconds which only gets interrupted by prolonged left bank commands. As pointed out earlier, the clockwise heading change is greatest when the Ny driven oscillation is dampened by hard over and held left SS inputs. So my feeling is that the PF managed to dampen the Ny oscillations that could have easily resulted in a total LOC.

The DFDR trace is Ny, which is not simply the lateral acceleration due to sideslip - there is a substantial contribution from the gravity component when banked. And as I said, at high AoA bank generates sideslip directly although there will be additional slip associated with accelerations along the y axis coming from sideforce. Up to 02:13:00 there is very little rudder application, then it is active for about 45 secs after which it goes quiescent again, and while the rudder application was active there is little sense of any reduction in the rolling motion, so I'm not at all sure that your feeling is justified.

Having written the above, then noted your latest comments, I am no further ahead in resolving what I still consider is the YD driving the Rudder and "leading" the Roll/Bank. I've had a look at the Pitch Attitude trace and find that maximum yaw coupled with side-slip tended to occur when pitched up with a RH roll bias.

I'm sticking with my feeling that it is lagging.

You say that, "In Alt2 the rudder deflection is controlled by pedal angle and yaw damper commands", and yet in the period we have been looking at, only YD commands have been presented to the rudder.

That is simply because the PF made no rudder pedal movement surely?

How or why does the Lateral Acceleration trace then synchronize with the YD / Rudder traces? To answer my own question, I have previously posited that the aircraft was effectively 'fish tailing'

They both synchronize with the aircraft dutch roll/roll oscillation motion - the measured lateral acceleration with bank angle plus some additional 'g' from yaw movements (assuming that Ny comes from that rear bulkhead accelerometer); the YD traces synchronize with yaw rate.

Its not important to the outcome, though helpful in understanding what is actually happening in what appears on the surface to be an aircraft in a benign stall and retaining some lateral stability, i.e. avoiding the 'spiral dive'

Yes I agree it is not a be all/end all point. One additional remark may be relevant though - when you get into or towards that high AoA/roll oscillation condition it tends to be a situation where roll due to sideslip is high and weathercock stability low, which is the condition for more positive spiral stability, which makes the reason for the continued roll right even more mysterious! [I've seen this before - in my youth we tested a free flight model which had this roll oscillation and even when we cut the complete fin off it simply wallowed in a straight line with no spiral divergence]

CONF iture

29th Apr 2012, 14:04

Side sticks make that harder to do. You can not tell what the other pilot is doing from your seat. Airbus isn't going to change anything so I guess noticing the little annunciator is their only clue what the other pilot is doing.
There is no such thing as 'the little annunciator' in flight.

The article has the merit to state the commun sense analysis regarding the sidestick concept by Airbus.

Never, the BEA would mention anything in that direction in the contributory factors chapter.

OK465

29th Apr 2012, 14:47

The estimated sideslip is sent to the PFD.

That's it. Full stop.

FWIW, with a reliable air data source, any sideslip will also cause the computed displayed winds on the ND to be in error. As a result, the GS displayed on the ND may also be erroneous during the uncoordinated condition.

These are normally such small variances, they are probably rarely noticed.

:)

ironbutt57

29th Apr 2012, 17:35

Thought, neither of the two 757's lost due to inaccurate ADR..granted for different reasons had side sticks, and yet nether one was control regained...also a "little sidestick forward" might well not been enough to counter the THS position....might have indeed required full stick forward, AND manual dose down trim...

Machinbird

29th Apr 2012, 17:55

I really don't see the problem here.

Ny is computed from an accelerometer mounted near the top of the rear bulkhead.
If it is to be used to estimate sideslip then the reading needs to be corrected for rudder sideforce (deflection) roll and yaw rates. If airspeed information goes south then so does the estimated sideslip.
So far as I can see, the only use of Ny and/or sideslip in the EFCS is a part of the lateral turbulence alleviation function.

In Alt2 there is no bank protection (and therefore no spiral stability term). Consequently the EFCS neither needs nor uses either Ny or estimated sideslip for roll control in this mode.
In Alt2 the rudder deflection is controlled by pedal angle and yaw damper commands. The yaw damper uses yaw rate; there is no Ny or sideslip term.

Consequently the EFCS doesn't use Ny at all when Alt2 is engaged.

The estimated sideslip is sent to the PFD.
In the old days before automation, we pilots were confronted with a bunch of steam gages, one of which was the old needle-ball indicator. Ny is the analog of the old ball indicator. The rule was "step on the ball" to center it. All the jets I flew including a straight wing one had a yaw damper controlled by a yaw rate gyro. If Ny is used in the EFCS, it is not for yaw damping, but for biasing out lateral g through rudder deflection.

You seem to be in the possession of inside information regarding the arrangement of the 'bus control system, however how certain are we that the bus EFCS in Alt2 does not have authority to "center the ball" in Alt2, and only sends a signal to the PFD equivalent of the ball telling the crew to center the ball.
This seems to conflict with:
Originally Posted by A33Zab
The estimated sideslip (elaborated in FCPC) is NOT used in ALT2(& DIRECT) and replaced by Ny rear accelerometer.

mm43

29th Apr 2012, 19:04

Hi rudderrudderrat,But the RH down going aileron would present more drag to the forward aircraft direction and induce a turn to the right, effectively "the wrong way".Yes, and that is exactly what I had concluded ...From Post #219 (http://www.pprune.org/tech-log/482356-af-447-thread-no-8-a-11.html#post7158429) ... This lead me to looking at the Inner Aileron traces, and I believe that the RH Inner Aileron when down was effectively creating drag, whereas the LH Inner Aileron when up was in the wake vortex and ineffectual. This drag on the right was causing yaw ...Owain Glyndwr;

Many thanks for sharing your experience in this debate.I've seen this before - in my youth we tested a free flight model which had this roll oscillation and even when we cut the complete fin off it simply wallowed in a straight line with no spiral divergenceMaybe just a case where the overall drag and the wake vortex conspire to provide a stable outcome.:ok:

jcjeant

29th Apr 2012, 20:22

Hi,

A nice graphic representation

http://i.imgur.com/buorH.jpg

The BEA cartoon ....

http://i.imgur.com/3JCdd.jpg

bubbers44

29th Apr 2012, 20:57

CONF, so the Airbus people that say there is an annunciator showing what the other pilot is doing is not true? I have never flown an Airbus by choice so assumed the annunciation from Airbus pilots was a true statement. Maybe there is no annunciation of what the other pilot is doing. That is even worse than what I thought about one pilot knowing what the other is doing In a dark cockpit. Please tell me this is not true.

Owain Glyndwr

29th Apr 2012, 21:50

Machinbird

You seem to be in the possession of inside information regarding the arrangement of the 'bus control system, however how certain are we that the bus EFCS in Alt2 does not have authority to "center the ball" in Alt2, and only sends a signal to the PFD equivalent of the ball telling the crew to center the ball.

Sorry, I don't have any inside information, but I do have a downloaded copy of an A330 FCOM which states that for Yaw control in Alternate 2:

Dutch roll damping is provided with authority limited to 4 deg in CONF 0, 15 deg in other configurations.
Turn coordination is provided except in CONF 0

So for the AF447 case the EFCS does not centre the ball, although in most other cases if does.

mm43

29th Apr 2012, 22:44

Adding to the above;

From Airbus A330 Instructors Support Manual -NOTE:
Depending on the failure type, ALTN is split in 2: ALTN 1 and ALTN 2. In ALTN 2 the roll control is roll direct. In certain failure cases such as loss of VS1g computation or loss of 2ADR, the longitudinal static stability cannot be restored at low speed; in case of loss of 3ADR it cannot be restored at high speed.

The yaw is then also degraded.It appears the comment on yaw applies to any of those conditions mentioned for ALTN 2.

CONF iture

30th Apr 2012, 02:40

Please tell me this is not true.
Nothing but the truth. For the 30 sec period the PF was full back stick, both captain and PNF were unaware of such vital piece of information.

Thought, neither of the two 757's lost due to inaccurate ADR..granted for different reasons had side sticks, and yet nether one was control regained...also a "little sidestick forward" might well not been enough to counter the THS position....might have indeed required full stick forward, AND manual dose down trim...
Correct but ...

In the Birgenair case, the PNF had that priviledge to witness how the displacement of the yoke by the AP was consistant with its own side instrumentation. He tried to tell the captain but maybe was not confident enough to intervene ...
The Aeroperu was a nightmare scenario where airspeed altitude V/S were all wrong. The end result was a CFIT where flight control displacements were minimal. In that case I agree, to have coupled yokes was not an advantage to the independant sidesticks (but neither a disadvantage).

For the THS, don't get me started again please. I am still amazed how the THS got almost full up :

automatically
under stall warning
the command by the sidestick for the period was more up than down but nothing that drastic

bubbers44

30th Apr 2012, 03:16

I have never flown an aircraft that one pilot did not know what the other was doing. What a strange way to design an airliner.

gums

30th Apr 2012, 03:28

Salute!

c'mon Bubbers.....

Airmanship!

Flew one jet with no second seat, so we flew "chase" and could only see/feel what the nugget was doing. No big deal, as just ask if he was putting in "x" stick.

In the Viper we flew chase for the guy's "solo" mission just to keep USAF happy. We had already flown a few hours in the family model. And like the 'bus, no visual or feeling what the nugget was doing with his sidestick.

I like the tacit feel and look of the yoke for a "crew" plane. but in this case the clue is to look at what the indicators were showing. 'course, seems the indicators were FUBAR and the crew had to deal with all the nuances of the reversion modes and.......

Gonna be a landmark finding report, as others have suggested.

ExSp33db1rd

30th Apr 2012, 03:34

I have never flown an aircraft that one pilot did not know what the other was doing. What a strange way to design an airliner.

Boeing even let you see what the Auto-pilot is doing, it was vaguely comforting on a dark night to see the controls columns and throttles gently rocking or rolling back and forth, just as they would do if the other pilot was hand-flying. Kept one in the loop, so to speak.

I used to have a bumper sticker on my briefcase - " Boeing, my way "

History for me now of course, but nothing will persuade me otherwise, bigotted if you like. Don't care.

The Daily Telegraph claims to have a leaked draft of AF447 (central Atlantic, all lost) final acc. reprt. Doesn't look too credible/accurate to me. Comments?

What don't you like about it, nothing new, just putting it all together in non-pilot-speak. Don't need the emotional stuff about children, and a few pax, of course, leave that to the other merdia.

Machinbird

30th Apr 2012, 03:44

Owain Glyndwr
Turn coordination is provided except in CONF 0That seems to be a pretty good answer (Once I figured out that centering the ball is a form of turn coordination-even if flying straight and level.:O) And yes, you do not need much rudder in most jets in cruise (CONF 0). Therefore it would seem that the Ny input is used solely in higher numbered Configurations for turn coordination.

Since I have seen a number of "unmasking" events in other aircraft, and the switch to ALT2 from Normal law, opens possibilities for unmasking events, I will reserve final judgement. Maybe looking at the yaw trim problem from the other direction, ie Normal law masking a slight out of trim condition rather than Alt 2 law creating a condition.

Nemrytter

30th Apr 2012, 19:37

Hi, I have two questions about the weather conditions experienced by AF447. A search hasn't shown up anything similar, so hopefully it's not duplicating what's been said before.

First: What was the OAT during the icing formation? I found some numbers in the BEA report that indicate a temperature of around -38C. Is that correct?

Second: Did the flight deck get any weather updates in-flight, or was their information based on pre-departure forecasts and their radar?

LIke I say, hopefully these haven't been discussed already, if they have it'd be great to get a link towards the relevant posts!

mm43

30th Apr 2012, 19:54

AF447 thread, page 27 (http://www.pprune.org/tech-log/376433-af447-27.html) will be a good place to start.

Also check the links to the three Interim Reports from the BEA which can be found on the 1st page of this current thread. You could also put "AF447 search index" (including the quotes) into the Google search engine and use the customized search engine that will be returned.

Nemrytter

30th Apr 2012, 20:37

Thanks for the tips. I've already read the interim reports but the info in the thread you link to is interesting.

roulishollandais

30th Apr 2012, 21:32

It is in French, excuse me :

http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/icons/laugh.gif franceinter y a-t-il trop de pilotes dans l'avion

They did not seem to have heard anything about a stall in RIO-PAR flight ! But everything is merveillous in french airlines and French pilot schools ! :\

http://www.franceinter.fr/emission-s...s-dans-l-avion

april 30. 2012 :mad:

Yves DESHAYES (CDB AF) Président du SNPL (Syndicat National des Pilotes de Ligne)

Michel POLACKO journaliste radio spécialiste aeronautique et défense Franceinfo

Christian MOREL sociologue autor de "Les décisions absurdes : comment les éviter", tome 2 Edition Gallimard Paris

:ugh:

infrequentflyer789

30th Apr 2012, 22:39

They did not seem to have heard anything about a stall in RIO-PAR flight ! But everything is merveillous in french airlines and French pilot schools ! :\

Sooner or later they are going to have to blame French pilots, French airline, French plane, or French pitots.

Might be why the report is taking so long... :E

bubbers44

30th Apr 2012, 23:15

I wonder how many of those 2900 hrs the PF had actually handflying and not monitoring? Not many I am sure and that is probably why he pulled up into a full stall at high altitude because he didn't understand he was in Alt law and had no stall protection. The second pilot in the left seat couldn't see what he was doing so got confused too. Then the captain comes up at the end and can't see what they are doing either with his limited time watching so can't see what he is doing with the SS. Why would any pilot at FL350 pull full back on the controls because he lost airspeed? All jets have loss of airspeed checklists showing proper pitch and power for weight and altitude. None say pull up to the stops. Boeings wouldn't let pilots do that. Unless both pilots were incredibly stupid.

Old Carthusian

1st May 2012, 00:52

A very good question Bubbers but it rather suggests that he was unaware of the aircraft and how it functioned. Never a good thing. The PNFs display should have supplied him with all the information he needed to determine the aircraft's attitude (but missing the IAS of course). But rest assured you can pulll the same trick in a Boeing - before this accident no doubt it was thought you couldn't stall an Airbus in this way. This accident is not aircraft design philosophy related.

bubbers44

1st May 2012, 02:44

It wasn't that long ago, 9 years, that we could all hand fly and an autopilot disconnect was a non event. Now that I have retired I hope things haven't changed much. Pilots need to be in control of their aircraft at all times. Automation is there to assist them, not fly the airplane instead of them. The great pilots I flew with 9 years ago knew how to hand fly. They didn't have a problem so only the new ones with little real hands on experience are the problem. All pilots should be competent at hand flying because your passengers deserve this.

roulishollandais

1st May 2012, 18:02

Pilots need to be in control of their aircraft at all times
It would be necessary that the pilots have control before to start the system, and may reverse initial conditions :

In the (relative) "old" time the pilot opened brackets for the PA/system. The pilot was "MASTER" in the effective aircraft :p, and the PA/system was "SLAVE" :oh:.

In the bad designed today's effective aricraft, the system puts pilots between brackets before he is sitting in the cockpit . The system is "MASTER" in the effective aircraft :p, and the pilot is "SLAVE" :oh:. ECAM throws him biscuits to keep him busy :(.

In the 8 billions Ariane 501 crash (Arianespace 4.june1996) the initial condition had been added, to compute the ground position of the rocket. At take-off the bug needed only 37 seconds to show it was the master of the rocket.
The perfect inquiry conducted by Jacques-Louis LIONS finished in less than 24 hours, written in 15 days, published in 6 weeks, showed that in computer systems we must not trust the system if we see no failures, but we must take it for faulty so long we have not been able to Proof it is safe, with all the best knowlege at this time.

promani

1st May 2012, 18:04

All pilots should be competent at hand flying because your passengers deserve this.

Obviously the airlines and their shareholders, in the case of AF447 the French Govt, do not agree with you. It is all about making a profit. As someone said in one of these threads, I think, that if airlines had their way there would be no flight crew, just like no staff on some subways.

Lyman

1st May 2012, 18:40

promani. see roulishollandais. I agree with both of you. It is ironic that the tables are turned on those whose allegiance is to machinery, that when faulted, the mechanism cannot solve its problem. It is done, finished. No escape....but for the humans who control the mechanism, who can reason, and problem solve.

Stubborn fealty to a false god. Make no mistake, the 447 flight was doomed at UAS onset, doomed, without the flight crew. That she crashed is perhaps due poor communication among the three pilot, but the a/c was lost prior anyway.

The problem was soluble up to well into STALL (likely), but only by the hands of man. Yet it is pilots who take the blame for the shortcomings of the automations. Once the a/c gives up, there is no pathway back to stable, save for the intervention of the safety pilots. The interventions were inadequate, but those who believe in pilotless travel would be wise to consider that because the rescuers failed, the new way may not be safe without at least the chance of salvation. Keep the Mark I, yes?

gums

1st May 2012, 19:17

Salute!

Good grief, are we now supposed to train our pilots to do fault analysis for 99% of the flight and then decide if Hal is doing O.K., and then "save the day" when Hal says "I can't do any more and don't know what's wrong"? BEAM ME UP!

Even if that approach is taken, then the humans still have to have the abilities and skills and judgement to fly the jet and get all the folks to the ramp. And they better have lottsa training for unusual flight conditions and loss of indicators.

Only reason I cut the crew some slack is the complicated reversion laws, unusual warning sounds and displays and such. I still think the PF thot he couldn't stall the jet due to the AoA protections ( poor term, but for another thread). Otherwise, I blame the crew.

I do not agree that the jet is so well designed that it is fool proof. Nor do I buy the argument that it did what it was supposed to, so no problem with the jet. I throw the foul flag, and point to the displays, confusing warnings, and on and on....

I see no point in discussing the yaw dampers and sideslip angles and all that stuff. Best I can tell is that the jet was fairly controllable, even at an extreme AoA and slow speed. So an attaboy to Airbus aero folks. And many "aw $hits" to the display and sfwe folks and training program. Takes 20 of gums' "attaboys" to equal one "aw $hit".

My feeling is that most of the pilots here think that better training and more hand-flying is vital. And then there's the human factors such as displays, warnings and complicated control law reversions. Am I way off base?

I thank the Lord that the primitive FBW system I flew had AoA as the prime limit, and the gee and rate limits secondary. Our yaw damper for the rudder commands was decent, but prolly no better than any jet that flew from the mid-fifties.

I say again that you could not get into the stall or "deep stall" without zooming up at 70 or 80 degrees of pitch and let the jet zip past the control law limits, then settle into the infamous "deep stall". If you were rolling and such, it was really hard to do.

I look forward to the final report and recommendations. Will be extremely interesting.

bubbers44

1st May 2012, 20:44

gums, I agree, yaw had nothing to do with this crash. Pulling back on the SS for no reason did and they would have been better rolling off into a steep bank than pitching up into a deep stall. He must have thought he was stall protected and forgot he was in alternate law. I still would like to know of those 2900 hrs how many were flying and how many merely monitoring an autopilot.

When I upgraded to captain from the MD80 to the B737 200 I did a lot of hand flying in the 80 to get my basic skills back to what they were. Flying skills can not be maintained by monitoring, only by doing.

jcjeant

1st May 2012, 21:54

I still would like to know of those 2900 hrs how many were flying and how many merely monitoring an autopilot.Assuming that this pilot fly only long haul .. and taking an average of 8 hours flight for each trip
Assuming that the pilot fly manually (generous here) ten minutes after take off and ten minutes before landing ( I'm being generous as it's already almost impossible he perform all take off and landings) .. this gives a manual flying experience (at low altitude) of 120 hours!

gums

1st May 2012, 22:01

So I look up the reversion laws and sub-laws and sub-sub-laws. Then read the footnotes and such, and then I get upset. Sorry, but I want/need something to hang my hat on.

And only thing I have if my touch and feel and experience. You know, "talk to me baby. What's this thing doing? I can help."

So Here's the notes from the A330 flight control reversion when outta basic control laws.

(a) alpha floor is lost. AOA is still monitored but warnings relate now to stall speed rather than AOA. Refer LOW SPEED STABILITY. If VS1G cannot be calculated due to loss of weight or slat/flap position information then there is no AOA protection at all.

Between alpha prot and alpha max, the sidestick commands AOA directly. Autopilot disconnects. TOGA lock is activated when AOA reaches alpha floor. This protection never allows alpha max to be exceeded. Stall AOA is greater than alpha max [ no kidding]

Protection totally lost if DUAL ADR failure or ADR disagree.

I was pretty good in school, but would have trouble on a test with these footnotes. Sheesh.

If WOW, then I don't care about other things not agreeing as long as the AOA probes are not all reading the same value and don't move when I pull or push a bit ( and would expect a warning of some kind). Of course, I could prolly "feel" some burble" "buffet" or wing rock or other things that let me know I am getting where I don't want to be.

So I do not let the 'bus design off the hook. I go with lottsa crew error in technique and coordination, but also question the basic design philosophy and training.

NeoFit

1st May 2012, 22:17

Hi,

this gives a manual flying experience (at low altitude) of 120 hours!
Sure, if such UAS event hapened while taking off or approach, the pilots were able to think about MAN PITCH TRIM, because they are trained for (ONLY at low altitude). [remember TAMRON 1994 LFPO]

Is there anybody believing at FL370 that THS had gone away -13 degrees ?

chris weston

1st May 2012, 22:54

All pilots should be competent at hand flying because your passengers deserve this.

Bubbers, 289 absolutely agree.

But ..... they don't deserve this they need this. The distinction between the two verbs is vital.

infrequentflyer789

1st May 2012, 23:17

He must have thought he was stall protected and forgot he was in alternate law.

This keeps coming up, in various forms, and I'm not sure I understand why.

If never trained in alt law I can see why he maybe missed the display and pnf call of it, and even the stall warning didn't give him a clue... but why was he anywhere near protection envelope in the first place ? The protections are there, I thought, to stop inadvertently straying outside the envelope, and (some modes) to give maximum performance within the protection envelope for specific circumstances - e.g. emergency terrain avoidance. What lead PF to desire maximum climb performance and then assume he was protected ?

Or put another way, you say PF was thinking:

"I can pull back as hard as I like to get maximum climb, because the plane will protect me"

But before that must be the thought:

"I need to pull back hard to climb fast (for several 000 ft) because... <???>"

This is right at the start, before the stall, to be clear.

What's the blank ? Surely unless we can fill that in the thought-he-was-protected is not relevant, and we are back to LOC in pitch being inadvertent. What little CVR there is seems also to support that - PNF says "why are you climbing" not "pull up mountain ahead". PF response seems to indicate he doesn't believe or understand he is climbing, PNF then insists he is.

chrisN

2nd May 2012, 00:43

2.5.12

IF, re: “ . . . pull back as hard as I like to get maximum climb . . .”

You seem to think he did this from the outset. He didn’t. If you look at the “stirring mayonnaise” chart,

[see:
http://www.pprune.org/tech-log/468394-af-447-thread-no-7-a-22.html#post6819601 ]

his pitch up inputs were neither full nor consistent at that time. Some have postulated that the stick back was inadvertent while he was using (too) large movements in roll. (PNF was telling him to make more gentle movements.)

It was after getting roll under control that he went to full stick back, AIUI.

Nobody knows what he thought or why, but one possibility is that after getting roll sorted, and the nose had started rising, with whatever alert noises were going off, he became confused; could not believe speeds, started to disbelieve some or all other indications, talked about crazy speeds, ended up stalled but ignoring the stall warning, had huge cockpit noise, (noted by somebody who has heard the CVR, it was reported) and thought, at least at times, that he had overspeed. So maybe he was pulling the nose up to try to slow down. Remember, at one stage he tried to use the airbrakes too, until PNF stopped him.

Lyman

2nd May 2012, 02:29

@ChrisN Nobody knows what he thought or why, but one possibility is that after getting roll sorted, and the nose had started rising, with whatever alert noises were going off, he became confused; could not believe speeds, started to disbelieve some or all other indications, talked about crazy speeds, ended up stalled but ignoring the stall warning, had huge cockpit noise, (noted by somebody who has heard the CVR, it was reported) and thought, at least at times, that he had overspeed. So maybe he was pulling the nose up to try to slow down. Remember, at one stage he tried to use the airbrakes too, until PNF stopped him.

He actually deployed the airbrakes, at 2:12:04. Three seconds later, PNF said,
at 2:12:07 "No, above all do not extend...." the rest of the sentence is not quoted, if it exists. Spoilers are deployed, not extended. Was PF reaching for FLAP? The "crazy speed" comment comes in conjunction with the spoilers deployed.....PNF has the most time in the 330, and my guess is he would not 'extend' the spoilers, he would "deploy" them.

At 2:10:10.4,
"STALL/STALL". just six tenths of a second later (2:10:11) the PNF: "What is that?" I propose PNF is not rhetorically commenting re: "STALL", he certainly knows what it is, but may be remarking on what caused the AoA to provoke the Warning, the extreme airstream noise that filled the cockpit. A robust turbulence that jiggered the vanes, and caused the Vanes to read correctly, but transiently....STALL/STALL.

bubbers44

2nd May 2012, 04:10

stall, stall to 99.9 percent of the pilots on the earth would mean stick forward.

Lyman

2nd May 2012, 04:19

Not at 2:10:10.4, bubbers. Not at M.80, and five seconds after autopilot quits.

And not with the nose down already, and he still had the AoA bug on the speed tape, it was nowhere near the bug. What do you make of the PNF saying, "What was that?" ? Recheck the stick trace. The Stall Warn triggers at the beginning of the climb? Then doesn't return til top of climb? For the Stall Warn to be authentic at the handoff, would have meant sufficient g to break something?

Wait a minute.......

PJ2

2nd May 2012, 06:33

infrequentflyer789;
Re Post #299 (http://www.pprune.org/tech-log/482356-af-447-thread-no-8-a-15.html#post7166279)...If never trained in alt law I can see why he maybe missed the display and pnf call of it, and even the stall warning didn't give him a clue... but why was he anywhere near protection envelope in the first place ?
I don't know why this aspect of the initial phase keeps returning to the thread either but there it is. Some accidents develop a mystique about them.

It's a big task to read through all nine or so threads I suppose but this has been discussed thoroughly and the results are consistent: - there are only a few reasonable theories which can explain why a rational, trained airline pilot would pull back half the available stick deflection and, with back-and-forth variations, keep it mostly in the NU position, even in spite of the fact that a minute later, pulling back does not arrest the rate of descent and the stall warning sounding almost constantly.

So far as training goes regarding Alternate Law, it is done in practically every simulator session as a result of some other scripted abnormality and the fact that the airplane is in Alternate Law, (1 or 2, doesn't matter...), should be instantly recognized and it should be thoroughly understood that one has an "ordinary airplane" on one's hands and must fly as a non-protected airplane. Memorized drills, QRH Procedures, SOPs and CRM are equally intended to provide quick and accurate ways to secure a compromised airplane AND to provide familiar "territory", guidance and therefore control in the face of "something wrong", to establish and maintain cockpit discipline, including the psychological and emotional responses such as perceptions, sense-making and fear which naturally accompany such events.

I posted the following graphic between a year and two years ago to show that far from unfamiliar, strange territory, flying in Alternate Law is fundamental knowledge of the airplane. This graphic is from an old CBT (Computer Based Training) module, ca. 1998.

If someone believes he is flying a computer platform which one "manages" (as we are told we are doing when using the autoflight system), and not an airplane which one flies, and expects the software design engineer and not an airline pilot of reasonable ability to retain the aircraft's innate stability and maintain control in all reasonable circumstances, then, to start, there is a major disconnect somewhere in the process of standards, training and checking and a major philosophical flaw in the approach to automation and its uses, benefits and HF problems.

I hope that the BEA Report addresses this question, among many reasonably and logically asked here.

http://www.smugmug.com/photos/i-KRNSqw4/0/XL/i-KRNSqw4-XL.jpg

jcjeant

2nd May 2012, 07:29

Hi,

Lyman
"No, above all do not extend...." Again .. a translation difficulty :)
In french he tell:
"non surtout ne ne les sors pas"
In french you can use "sors" for the action of extend flaps or deploy spoilers or extend gear or pulling a rabbit out a hat or take a walk
Je sors les flaps
Je sors les aérofreins (spoilers)
Je sors le train d'atterrissage (I extend the landing gear)
The word (verb) "sortir" can be used for various actions and its meaning depends on the context in which it is used
Finesse de la langue française
Finesse of the French language :)

Lyman

2nd May 2012, 13:52

Hi jcjeant.:ok:

I learned at school that 'sortir' meant to 'leave, or depart'. Hence, "Sortie". "He flew three sorties today"......

"Je sors l'ecole". English is the language of aviation, by treaty, but I can understand the stress, so French is not unusual in this instance, so I don't get how 'depart' attaches to the cockpit conversation? (or that my take is 'wack'?)

Are you saying that their conversation was sloppy, or that the translation by BEA is sloppy?

merci

A33Zab

2nd May 2012, 14:43

Since english is not my native tongue, I have to use:

SIMPLIFIED TECHNICAL ENGLISH
Specification ASD-STE100
European Community Trade Mark No. 004901195
International specification
for the preparation of maintenance documentation in a controlled language.

EXTENSION (n): 1. The “action” when something extends

Approved Example: MAKE SURE THAT THE EXTENSION OF THE AIRBRAKES IS SMOOTH.

DEPLOY (v),
DEPLOYS,
DEPLOYED,
DEPLOYED: To move into a position of operation from a position of storage
NOTE: Use for thrust reverser or drogue chute operations only.
For other meanings, USE: EXTEND, RELEASE

Approved example: KEEP PERSONNEL AWAY FROM THE AIRCRAFT WHEN THE THRUST REVERSER DEPLOYS.

Evidence is in the FDR spoiler traces!

Lyman

2nd May 2012, 14:53

Thank you sir. In BEA #3 the chronology shows that the spoilers were deployed; three seconds later, the PNF states: "Do not extend" etc. In this case extend is not a noun, it is a verb?

Can you find where the spoilers were later "stowed"? I haven't found it yet.

(will post pp and exact quote, looking)

Do you have opinion on 'sortir'?

thank you

addend: For purposes of discussion, I am relating the events only to the verbal record, not the FDR. The DFDR was not a part of the problem, essentially, only a witness to it. Blending the FDR traces with a discussion amongst (the three) pilots (actual) is in a way a bias.

Lyman

2nd May 2012, 15:14

@ PJ2 ....."There are only a few reasonable theories which can explain why a rational, trained airline pilot would pull back half the available stick deflection and, with back-and-forth variations, keep it mostly in the NU position, even in spite of the fact that a minute later, pulling back does not arrest the rate of descent and the stall warning sounding almost constantly."

I think I agree, but would suggest the insertion of an alternate to 'reasonable'. Can we try 'obvious'? Many possibilities have been mentioned, and rejected, in some cases, without objectivity. Bias is a subjective species of opinion, and should play no part in a detached investigation. "Reasonable" is a matter of opinion, and led in some cases to the repetitive presentation of fatal accidents, simply because the cause was not 'reasonable'.

Mention airframe damage, and the gallery frowns and stomps its feet, likewise computer failure of massive nature. In this regard, I have great respect for BEA, they do not make conclusions, only supposition. The final report will be similar. I expect an objective and thorough document. Throughout each report, the authority is careful to not make dramatic conclusion. The downside is that by exclusion, readers of the reports "conclude" fact. Damage, for instance, is possible, but not seriously addressed; therefore the popular conclusion is "Intact at Impact". A serious sceptic would respond: "Define Intact"........

jcjeant

2nd May 2012, 15:17

Hi,

Blending the FDR traces with a discussion amongst (the three) pilots (actual) is in a way a bias.
Indeed....
FDR traces did not reflect what the pilots see on the panel (instruments)
The FDR is the only witnesses of their actions
In flight .. the pilots did not real-time access to the FDR
They do not have a printer showing a graph (similar to those of BEA) of the FDR data recorded (and same for the ACARS)

Lyman

2nd May 2012, 15:34

jcjeant. tres bien.

I can't remember how long ago it was, but I asked a question re: FDR and real time flight management.

The FDR is a resource. It is in fact a pilot with a phenomenal memory. The downside is that this resource is wasted on Court filings, arguing lawyers, and biased professionals, with an agenda.

What in God's name prevents the acquisition, analysis, and exploitation of the FDR in real time? Inertial records become flight path cues, etc.? It is a crime, to waste resources. Lives are at stake.

merci, rant fin

gums

2nd May 2012, 15:57

@ Lyman.....

The relatively intact impact and wreckage pics was what prompted me to postulate the "deep stall" theory. Then I had good inputs from others here and got to see some FCOM documents and so forth. It became obvious that you could fly the 'bus into a very deep stall and have reasonable lateral control and even pitch control. But sooner or later ya gotta relax the back pressure or even push the stick forward and see what happens.

Gotta tellya that the HUD I had in the Viper and Sluf used real time inertial data for the flight path marker and AoA and vertical velocity and alt and speed and heading........ When you see the AoA bracket at the top of the HUD and speed is slow......duhhhhhh.

I am having my LEF failure video digitized so all can see how neat the HUD was when you are making the first landing attempt with serious stuff not working like it's programmed to do.

Lyman

2nd May 2012, 17:03

gums

howdy. Since you're USAF, you may be familiar with John Boyd and his thirty second challenge at Nellis. Col. Boyd was not well liked by Brass, he had no time for pyramid types.

If you know about Boyd's flat plating trick, you may know how stable the HUN was in totally departed flat aspect, all drag, no lift, an object of diminishing energy, giving it up for the 'cause'. It won for Boyd his deserved rep, and cred.

How different is 447's 330? Not much, I think. The a/c derived its 'stability' in deep Stall from spill, not flow.

The HUD, inertial cueing and other military benchmarks are expensive. Very expensive. If Joe Q. Public knew how safe he would be if the beanies spent some dough, he would revolt, as did the Air France pilots, when they finally realized how they had been waltzed by the company v/v PITOT THALES.

It is way important to keep the real deal on the down low, lest profits fall with fewer and fewer fatalities, as equipment is brought (at great expense) into the NOW, out of the THEN.

447 remained stable because she had her airmass controlled. She wasn't "directing" the flow, she was not in flow. She was in "spill". One can fly drag, as well as lift; ask a sailor, or read Boyd's "ACM" white papers.

You speak 'boydese'?

cheers, see you at the bar.

wings of tin

gums

2nd May 2012, 17:18

Salute!

@Lyman

Don't get into Boyd other than the OODA. The guy may have helped get the Viper and Eagle and Hornet into the inventory, but his A2A claims are grossly embellished, and I know folks of his vintage.

As RR and others have posted, the OODA loop was in play for AF447. The thing I see is the "d" and the "a". Ya gotta give the jet a few seconds to respond to whatever you or Hal is commanding. Then you decide and act.

I shall still ascribe most of the tragedy to pilot actions, but I'll also add some human factors, crew coordination and design philosophy/implementation factors.

This will be a landmark accident report.

G

A33Zab

2nd May 2012, 17:20

Sorry to correct you again:

STOW (v), STOWS,
STOWED,

STOWED:
To move out of a position of operation into a position of storage.
NOTE: Use for thrustreverser or drogue chute operations only.
For other meanings, USE: PUT,RETRACT

French isn't either the mother tongue.

http://i474.photobucket.com/albums/rr101/Zab999/SpoilerTrace.jpg

Lyman

2nd May 2012, 17:30

What's left after correction is what is correct, the Truth. It's all good.....

thank you Captain.

PJ2

2nd May 2012, 17:47

Lyman;
ee, but would suggest the insertion of an alternate to 'reasonable'. Can we try 'obvious'?
No, that loses/reinterprets my intended meaning. The notion of "plausible", associated with "reasonable", isn't the same as "obvious".

PJ2

OK465

2nd May 2012, 17:57

Momentary off topic:

Boyd's 'trick' worked for one and only one reason...

He positioned his 'victim' close enough behind him that, keeping in mind the slight delay in reacting, there were actually only two outcomes possible if the 'victim' attempted to 'follow' him,

the 'victim' either accepted the overshoot or...the 'victim' was willing to HIT him.

Boyd did not depart the F-100, he simply used max instantaneous turn capability with some thrust modulation and a loaded rudder reversal, all at speeds & AOA above the stall.

If the A330 simulation is near accurate, the A330 is quite a bit more stable approaching and entering a stall than an F-100 for which...the word 'squirrel' comes to mind. :}

Back to the game...

Lyman

2nd May 2012, 18:02

Yes, exactly, I was trying to point out the difference in our respective povs.

I did not mean to "correct" your post, only a temporry mod, to frame the difference between "Plausible", and "apparent".

Implausible, unreasonable: "It doesn't make sense".

Obvious, apparent: "Sense or not, there it is." Some things that don't make sense can kill people, and judging something by how much logic it contains can mislead. Just my opinion. As a matter of fact, the less sense evidence makes, the more one should be open to "Implausible". A parenthetic to Occam?

cheers

DozyWannabe

2nd May 2012, 19:13

Mention airframe damage, and the gallery frowns and stomps its feet, likewise computer failure of massive nature.

Only once the evidence came back that suggested pretty conclusively that neither had occurred. Prior to that the most accurate thing anyone could say was that it was unlikely, and attempt to explain why it was unlikely with the facts at their disposal (as I did).

It's one thing to think outside the box in an open-minded fashion - but what tends to be the case in any incident or accident involving Airbus is that some people - usually the same people each time - will approach the problem with a pre-conceived conclusion in mind to support a personal agenda which pre-dates that particular incident.

@chrisN - I don't think they ever got roll under control in any meaningful sense, because the PF was trying to use fistfuls of aileron throughout the sequence. Prior to the stall gentle aileron may have been effective, but post-stall the only thing that can effectively control roll is rudder.

gums

2nd May 2012, 19:14

Salute!

Thanks Okie, that about nails it. Biggest thing Boyd sold was energy management in the new jets. OTOH, I think Yeager and others way back had already cracked the code.

WRT to AF 447, the swept wing jets share many aero characteristics going all the way back to 1950. So Boyd and others figured out that you could pull real hard and not get the classic stall warnings and such that the previous planes had. What you got was a lotta drag, and a need to use rudder versus aileron for directional control. Buffet and burbling and such depended on your jet. A-7 and F-101 that I flew let you know real early. F-102 and F-16 were smooth as silk. First clue you had 'stalled" was vertical velocity of 10,000 per minute and speed below 150 knots. Sound familiar?

Biggest thing about the OODA concept for AF447 is the the "O" and "O". The big jets have lottsa inertia and momentum and such. They are not gonna snap roll in a second. They are not gonna overspeed in 10 or 15 seconds. You don't have Mig at close 6 o'clock or a SAM headed your way. So a few seconds observing, then orienting can really pay off.

later from this old man.

chrisN

2nd May 2012, 20:00

Dozy, it was one of the experts who I thought said they got the initial roll under control – in a part of a thread about PIO or whatever it is called nowadays.

But it is not particularly relevant to the main point, which is that PF’s initial pitch inputs seemed to many to be incidental, even accidental, to his roll over-corrections. The full stick back came later.

Regards – Chris

Lyman

2nd May 2012, 20:17

@ Doze.... "Only once the evidence came back that suggested pretty conclusively that neither had occurred. Prior to that the most accurate thing anyone could say was that it was unlikely, and attempt to explain why it was unlikely with the facts at their disposal (as I did)."

I agree, Doze. I think it is unlikely, but it is possible. For a suspicion, I think the roll rate out of AutoFlight was pretty impressive, and Direct involves the outers, no? Damaged Right aileron, stuck a little, UP? A chronic right roll,then. Even after Roll was 'sorted', the a/c kept turnong to the right (Skidding?). Bent actuators? Who knows.

gums, don't short sell Boyd, he was a genius. O, and O were not new, they are nothing more than situational awareness. Boyd put S/A together with Decide and Act to close the circle, but there is more. Four parts OODA is four too many, to be triumphant requires instantaneous decisioning. Boyd's point was to make O,O into OO, then into ODA, then DA, then A.

No soldier who pauses to think will live, let alone prevail. Practicing OODA was prelude, if you are still in OODA, you should not be engaging the enemy. OODA teaches competence, and with competence come experience, and with experience and knowledge,wisdom. With wisdom, one can try for Intuition.

Boyd's philosophy hadn't to do with partitioning the process of thought/action, but in developing the means to enter the enemy's mind, and baffle him by pre-empting his best work.

Until one masters OODA, one cannot get to ODA, or DA. And the Goal is ACT.

For if you think, you die. Anyone who wants to get a glimpse of Boyd's genius must read this: Creation, and Destruction. He was way ahead of his time, and could have kept Einstein guessing, and in awe.

Any pilot at 35000 in ITCZ and on autopilot who doesn't know instantly where to put the nose and the throttles should OTTO dump, should not be at 35000 in the ITCZ at the controls of a beast. Keeping up is not enough, one must get to, and remain, in front.

Lonewolf_50

2nd May 2012, 20:58

For PJ2

My answer to the quiz was "B" without looking anything up. :}

For OODA loop:

If your instrument scan has broken down, how are we talking about OODA?

Observe and orient seem to me to require actually seeing something, knowing what it is you are seeing, and using what you know to set up some choices for a decision.

The PF seemed to be going to D without effective OO, hence the A's were not suited to his dogfight, a 1 v 1 with an A330 when he had a wingman there to assist ... too much analogy, sorry. :cool:

Cheers.

DozyWannabe

2nd May 2012, 21:05

Dozy, it was one of the experts who I thought said they got the initial roll under control – in a part of a thread about PIO or whatever it is called nowadays.

I'm no expert, but judging by the DFDR output, every single roll input prior to stall was in excess of what was required to correct it. I'm of the opinion (as a non-expert ;) ) that the initial roll was turbulence-induced, and that the initial overcorrection by the PF led to PIO in roll. The reason I'm fairly confident about the latter is that we know for certain that neither of the F/Os in the flight deck had ever done any high-altitude manual handling training, and the low-level manual handling they had done requires considerably greater stick deflection than required or desired at cruise level.

But it is not particularly relevant to the main point, which is that PF’s initial pitch inputs seemed to many to be incidental, even accidental, to his roll over-corrections. The full stick back came later.

I'm not so sure (but remember - non-expert!). Part of the reason I leapt at the chance to try this in the sim was to find out exactly how the real Airbus sidestick behaved. Looking at the DFDR, the initial pitch input varied between about 10-50%. From my subjective perspective based on the sim scenario, 50% deflection requires significant positive movement to overcome the spring of the centring mechanism - very different from a computer joystick, where that kind of deflection is fairly easy to achieve unintentionally.

Everything about this looks to me (as a relatively well-read layman) like a textbook startle response, followed by breakdown of instrument scan and intra-cockpit communication. It may be fair to censure the crew for not following UAS procedure, but it is not fair to censure the crew for attempting to improvise and fumbling the recovery, because the institution to which they belonged had never provided the training required to do so effectively.

@Lyman - I know a few disagree with me, but I don't think the roll was induced by positive autoflight intervention or mechanical failure. Everything I see is consistent with the autopilot disconnecting in the middle of a turbulence event, from which it was trying to correct. Rudderrudderrat's mention of rudder trim is an interesting one because if autoflight had been using it, it may have left them with a slight roll tendency until corrected, but even then nothing that would require inputs as aggressive as those made by the PF.

@gums - See above. Nothing in the traces indicates aileron damage. I'd need to get the books out, but I think the outer ailerons are centred and locked when manual control is taken at high altitude, which is why the outer aileron traces centre at A/P disconnect. The take-away from the aileron traces for me is comparing the significant difference in magnitude between the corrections made by autoflight (indicating the required amount of deflection for positive correction at high altitude) and those made by the PF (considerably larger and way in excess of that required). OK, so with outer ailerons locked the inner ailerons would have to work a little harder - but not that much harder!

Lyman

2nd May 2012, 21:14

Wolf.

The pilot seems to have skipped the D as well, all we see are seemingly random "A's"....... Taking action whilst unsure of what to do was not in the instructions. At least when I learnt. It would be interesting to read his..... Don't just do something, sit there!

Lyman

2nd May 2012, 21:20

Sorry. Not turning then, but changing heading clockwise? Hazelnuts, come back!

HazelNuts39

2nd May 2012, 21:36

A chronic right roll,then. Even after Roll was 'sorted', the a/c kept turnong to the right (Skidding?). Bent actuators?
From IR#3, pages 41-42: The results obtained reveal that before approximately 2 h 10 min 40, i.e. the time when the aircraft was climbing at about 37,000 ft, the parameters recorded (angle of attack, normal load factor, and attitude) fluctuated around the simulated parameters, indicating the presence of turbulence. After this time, this turbulence appears to disappear and the parameters simulated and recorded are highly consistent.Between 02:10:40 and 02:10:50 there was little activity on the side stick laterally, no deflection of aileron or rudder, no roll.

PJ2

2nd May 2012, 21:49

Lonewolf_50;
My answer to the quiz was "B" without looking anything up.
Yes, it is, but of course determining the correct response is not the reason I posted the slide from a 1998 CBT on the A340/A330, ;-)

This is not as complicated as "OODA" and Boyd. The appropriate and correct responses are already there in the SOPs etc and do not require sophisticated techniques to address and correct.

If the instantaneous and then sustained pull-up had not occurred as in the other thirty-odd UAS events there would be nothing to discuss here.

The details of roll, yaw and subsequent confusions when stall warnings "quit" and then began again are all post-facto of the initial response. The devolution of aircraft stability and control are a direct consequence of loss of energy, entry into and sustaining of the stall. Why such sustained back-pressure occurred should be the subject of the Report.

Dozy, contrary to your observation, the data shows that the initial L>R>L etc roll was very quickly contained and controlled.

I cannot accept that a sustained pitch-up was the result of inadvertent stick-handling, not, at least, without also accepting that the most basic principles of high-altitude, swept-wing flight and the resultant attempts at manual control were for some reason not understood.

In my view the pitch up was intentional but the results were not anticipated and therefore not intuitively understood.

This is a matter for the Report to handle and somehow explain.

Lyman;
Don't just do something, sit there!
I said that more than a year ago..."do nothing". The observation was completely mis-interpreted. I've done this in the sim enough to know that "doing nothing" was the safest response in the moment, then collect one's thoughts, call the abnormal and take command of the airplane while the PM gets out the QRH to fine-tune the already-nominal pitch and power settings. That is what "do nothing" meant then, as now.

PJ2

Lyman

2nd May 2012, 22:05

@PJ2....I cannot accept that a sustained pitch-up was the result of inadvertent stick-handling, not, at least, without also accepting that the most basic principles of high-altitude, swept-wing flight and the resultant attempts at manual control were for some reason not understood.

Let's be more careful. There was no "Sustained Pitch UP" (Re: STICK). There was an overall average of NOSE UP, as seen from the results, but the inputs were not without interruption, and to claim so must be by mistake, yes? Many Nose Down inputs, changes in PITCH UP and DOWN, etc. The initial input was NU, followed by several Nose Down inputs. It can be inferred from such language that the PF set and maintained a climb, only. NO. What can be concluded, at least by me, is that there was handling that took different iterations. The climb was not monolithic, it was more haphazard, and resulted imo from a lack of awareness of VS, PITCH, and A/S, all of which were at different times, wrong, accurate and/or NCD. Or BLANK.

Yes, I meant to attribute "do nothing" to you, but had forgotten who posted it, my bad.... I was one who knew precisely what you meant, and regret that others made such a deliberate misunderstanding of your words. Clearly, with an a/c rolling at 4.5 degrees/second and nose down, Input was required, as evidenced by the work of the handling pilot. My previous comment re: a/ploss and the PF needing to be instantly prepared stands, but to me does not conflict with your counsel for patience, and calm......

with respect always

HazelNuts39

2nd May 2012, 22:15

@Lyman,

Between 02:10:07 and 02:10:17 the pitch attitude steadily increased to 11 degrees NU. The side stick position fluctuated between 1/4 and 3/4 NU, never went to ND.

Lyman

2nd May 2012, 22:21

Yes, and the a/c attitude needed this input, for in the words of BEA: "Until the Pitch reached 10 degrees Nose UP, and the aircraft began to climb." It is a big plane, and the Pilot seemingly was behind in the a/c lag, and momentum, once moving... Here, in PITCH, as we also see in ROLL. His PITCH excursive inputs mimicked the ROLL, he had a mix of Impatience, "Catch-Up" and Adrenaline, all three rsponsible, perhaps in toto for this crash......

HazelNuts39

2nd May 2012, 22:23

i think you're misquoting BEA, again.

Lyman

2nd May 2012, 22:26

Standby...PAGE NINE

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.

DozyWannabe

2nd May 2012, 22:26

Dozy, contrary to your observation, the data shows that the initial L>R>L etc roll was very quickly contained and controlled.

Hi PJ2,

Help me read the traces, because what I see is a considerable amount of roll oscillation for about 30 seconds immediately after disconnect, which dovetails nicely with the near-full deflection of the inner ailerons (timecode approx. 2:10:05-2:10:35). Immediately after this the inputs reduce in magnitude and roll starts to stabilise (consistent with getting a feel for the aircraft), but shortly thereafter the aircraft enters the approach to stall regime and control seems to run away from the PF.

As a non-pilot I don't have the subjective knowledge to say how long it should take to contain, but 30 seconds seems like a fairly long time to me.

Please correct me if I'm barking up the wrong tree.

@HN39 - I don't think he's misquoting - at least not dramatically. What he's doing is interpreting the phrase as meaning things happened sequentially rather than concurrently. Whether due to translation issues or problems with wording, it's difficult to say one way or the other when taken out of context. Put in context with the rest of the report though, it's clear they mean that the aircraft climbed concurrently ("at the same time" - for non-native English speakers) with the increase in pitch attitude.

Lyman

2nd May 2012, 22:36

Dozy. Yes. Sequentially. Can one read it another way? "As the Pitch increased beyond ten degrees NOSE UP, the a/c continued its climb?" Would this example be more accurate to describe what it is you think happened?

As written, it explains the pilot's sensed need for Nose Up, the a/c was not climbing until it reached ten degrees NOSE UP.....

The language is quite critical, and HazelNuts39 can help with the actuals, for as written, it describes an a/c caught in a massive downdraft. And/or a pilot believing there was such a thing happening.

French or English, writers get paid by the word, so long as sense can be made. Why does BEA mention the PITCH and the Climb? Because they need to associate the two. And ordinarily, since it would not be necessary to link PITCH UP with climb, what is it they are trying to explain? I think their meaning is that the a/c was reluctant, sluggish even, in acquiring climb.....

DozyWannabe

2nd May 2012, 22:43

Lyman - I don't think so.

The airplane’s pitch attitude increased progressively beyond 10 degrees and the plane started to climb.

The important word there is and. If the climb did not begin until 10 degrees nose-up had been reached, the correct word would be "then". "And" simply states that two things happened, whereas "then" would imply one thing happened after the other.

"As the Pitch increased beyond ten degrees NOSE UP, the a/c continued its climb?"

All this means is that nothing has changed in terms of general aircraft response. The pitch angle increases beyond +10deg, and the aircraft continues the climb it began as soon as the aircraft began to pitch up past the cruise trim pitch.

Lyman

2nd May 2012, 22:48

I think you may be correct. You may also be wrong.... I would like some clarity before I claim to be right or wrong. As I say, the language here, is critical....

Humor me. Pause, and do not go immediately to the FDR, the traces. More important here, is not what actually was recorded in the FDR, but what the pilot determined the response (of the a/c) to be.

I can ask again, the Pilots had no access, nor did they care, re: DFDR. What was the a/c saying, doing? If you were looking at a ND on the display, and had held aft stick for ten seconds, would you be confused? I would be, I might even puke... Why? because if I am worried about Overspeed, and she won't climb, we are all dead, painfully. There is an explanation for us in the actions of the pilots, and hauling out the traces can be distracting. They will not morph, they will be there forever. The crash happened once....... To gain an understanding, one must not start with an opinion of the pilot's skill level, but what his actions are saying to us...

"Started to climb". When, exactly? at what PITCH?

The PITCH was in transit, UP. Increasing to and through ten degrees. Not Eight? Not Nine?

By the way, the original text stated "..and the a/c began to climb.."

When was the text altered? Anyone?

gums

2nd May 2012, 23:09

Salute!

Gotta go with PJ

If the instantaneous and then sustained pull-up had not occurred as in the other thirty-odd UAS events there would be nothing to discuss here.

The details of roll, yaw and subsequent confusions when stall warnings "quit" and then began again are all post-facto of the initial response. The devolution of aircraft stability and control are a direct consequence of loss of energy, entry into and sustaining of the stall. Why such sustained back-pressure occurred should be the subject of the Report.

Seems to me that the OODA concept is the basic instrument crosscheck, or am I way off base? I am not talking about air-to-air combat, but basic IFR flying.

Some aircraft, such as the lites I flew, had a very short "time constant". So 1 or 2 seconds without action could be bad ( think 300 degrees per second roll rate or higher, and 5 or 6 gees within a half a second). The bigger and heavier planes are much more forgiving in this regard. So 5 or 10 seconds to figure out that initial actions weren't working does not sound unreasonable.

When we all meet in that hootch bar in the sky, we can ask the guy what the hell he was thinking. I have a feeling that he would do the drill differently now that he has also had the chance to see the traces and such. Ya think?

DozyWannabe

2nd May 2012, 23:19

Lyman, neither you nor I can even begin to assume what the pilots were thinking or trying to do. In this case you have provided a phrase which out of context appears to be ambiguous as to the sequence of events. I have suggested that elsewhere in the report it is fairly clear as to what they mean (I'm not going to dig it out now - jetlagged to buggery).

The acid test is to look at the DFDR trace - the nearest to raw data we have, and see what was going on with the data. By telling me that I can't do that not only have you shut off the most effective avenue for resolving the ambiguity, but you've made it look like you have some reason for not wishing to do so.

So, for your benefit I'll use the fact that in the "1.1. History Of Flight" section, the BEA have placed events which happened either concurrently or in very quick succession into small, concise paragraphs, each of which starts with a timecode. The extract you provided is contained within one of these paragraphs. I put it to you that if there was significant lag between the aircraft pitching towards +10deg and the aircraft only starting to climb once +10degrees was reached, then this would have necessitated separate paragraphs for each event.

For the rest of us, let's look at the trace. The aircraft reaches +10deg nose up at approx. 02:10:16. At this point vertical speed is already approx. +3000fpm.

The climb begins in earnest (i.e more than +1500fpm) with the pitch attitude between 4 and 5 degrees.

As an aside, in my business it is vital to understand when events are happening sequentially versus concurrently, because the consequences to design philosophy and problem-solving are very different depending on which method is used. In the best-case scenario, the documentation is very explicit as to this, but I've read my fair share of lousy documentation from which it has to be inferred. Not to blow my own trumpet, but I'm pretty good at distinguishing these inferences based on context these days...

Lyman

2nd May 2012, 23:19

....So 5 or 10 seconds to figure out that initial actions weren't working does not sound unreasonable.

Given 447's rate and bank angle at handoff, she would be banked right at 56 degrees after ten seconds.... PITCH? I have no idea.

Did you fly the T38? 720 degrees per second. o lee she itt.

DozyWannabe

2nd May 2012, 23:37

If they were getting that bank rate in clear air, then yes - prompt and expedited correction would be necessary. But they were *in turbulence*, and even in light chop, an aircraft can attain split-second accelerations that if continued would have them saying "Hi" to astronauts on one direction, submariners in another, and Australians in roll (if you're from the Northern Hemisphere).

But these accelerations are transitory, and even if they weren't we're talking 8.6 degrees of bank at handoff - most airliner turns can go between 10 to 25 degrees without unduly scaring us SLF.

In my opinion, there was time to wait and observe - but given the situation and the way it escalated I'm sympathetic to the instincts of the PF.

Please remember that I am sympathetic to the crew's position in general, and always have been. They were faced with a situation that for whatever reason their employers had not fully prepared them for either in terms of understanding or in terms of how to improvise if the published procedure didn't work. Based on the incomplete information we have now, my opinion is that we have a complex, systemic failure here - not a cut-and-dried case of pilot error (in fact I believe firmly that such cases are fairly few and far between at the ATPL level - just look at the stick I got on the Paul Holmes/Erebus thread for advancing that viewpoint!).

If I can abandon my usual desire to be dispassionate, looking at the traces to answer PJ2 showed me a period of 8-10 seconds where the roll had been ironed out and it looked like the PF was starting to get on top of things, only for the Stall Warning to kick in and startle him into fumbling the controls - pretty heartbreaking.

Lyman

2nd May 2012, 23:51

That is an excellent point; it can be counterproductive to attempt to smooth out a turbulent ride...

I meant to suggest that with impatience, "catch up itis" and a squeeze of Adrenaline, overcontrol seems to have been the order of the day, In PITCH as well as ROLL. Did the pilot fear a loss of control, and that manual inputs were critical? I sense that he did, at least somewhat. Before Colgan, I would have simply rejected the thought that a pilot would persist in the exact wrong thing.

But Colgan had a PNF also, and she did not "get" it either...

Dozy, in all honesty, do you think the Bus might need a special dose of targeted training? Because the bottom line is that all three pilots were at a loss, without a hint of the right "Stuff". Can the platform be that inscrutable to three independent airmen?

DozyWannabe

3rd May 2012, 00:29

It's not "the platform". Escalating situations from UAS have claimed a 727 and two 757s just to start with, and likewise several Airbus FBW widebodies have been recovered from UAS successfully while the pitot tube problems were being solved.

Trying to make it about Airbus is to miss the point. The issue is systemic to the industry as a whole, and that issue is airline management forgetting what it is that their businesses actually *do*, which is ferry hundreds of people at a time from one place to another in a metal and composite tube which spends most of it's time at 30,000ft and doing over 500mph. Consequently they forget that while safety has improved considerably over time, the fallout when something does go seriously wrong tends to be catastrophic, and that even if the chances of something going wrong tends to be in the 1 in 10,000 range or lower, the two people at the sharp end have to be fully prepared to do everything in their power to rescue the situation. And that while SOP and emergency checklists go a long way to mitigating the risks, only confident, competent basic airmanship - including stick-and-rudder and basic principles of flight - can save the day on the occasions they don't.

The junior crew on this flight didn't need an encyclopaedic knowledge of the A330's systems to recover, all they needed to remember was the stuff they learned back when they were doing their PPL - namely recognising the symptoms of, and recovery from, a stall (which are more-or-less the same whether you're flying a microlight, a space shuttle or everything inbetween). Unfortunately airline management don't see fit to mandate revision of the basics like this by and large, probably considering it too costly.

gums

3rd May 2012, 00:44

Thank you, Doze.

You've nailed it. And still makes me cry.

The "mission" is to get the SLF home or to a vacation spot. There's more to the job than simply being a systems manager.

Gonna be an interesting final report, ya think?

DozyWannabe

3rd May 2012, 01:16

A quick postscript re: ColganAir 4805 -

While the situations look superficially similar (pilots out of their depth fumbling the controls), the human factors aspects are considerably different in nature.

Firstly to address Lyman's point, it wasn't just the F/O in the Colgan case who made fatal mistakes, it was the Captain too. While it's true he was inexperienced and apparently below average in terms of ability, the crux of the matter was that in a sane world, both pilots should have called in sick that day - both for exhaustion, and the F/O for what appeared to have been either a bad cold or mild 'flu on top of that.

But Colgan, along with most if not all regional subcontractors at the time, operated a business model in which exhausted pilots were the norm, and that exhaustion was a direct result of those pilots being underpaid and undervalued, while the beancounters and management crowed about their profit margins despite rock-bottom fares. I'm tempted to go on a tear about deregulation, but I'll leave it for now. All I will say is that if I were king, the Colgan executives would have been up on as many corporate malfeasance charges as I could find, and a new statute of corporate murder created just for them.

Air France has had it's troubles over the last decade or two, there's no doubt about that - but for the most part it has treated it's pilots as well as your average flag carrier as far as I know. The misapplication of automation and atrophy of manual skills/aeronautical knowledge is not restricted to them. None of AF447's crew were sick or exhausted, they simply ended up in a situation that was beyond their abilities to understand in time - and what started as a benevolent gesture from the Captain (designating PF as relief pilot) had the unfortunate consequence of putting the least experienced crew member in charge when things started going wrong.

Lyman

3rd May 2012, 01:36

Just as it is difficult to paint with a broad brush without missing a few things, it does an open mind some dishonor to get too narrow. So I applaud your broad view, but will be happy to point out where you miss some things after the report. There will be some knocks on the Bus, let's wait and judge the platform in the context of your well put post in its defense.

In a spare no expense world, 447 makes Paris, and there will be others. There is never a justification for scrimping when the outcome is brutal, but if cost is fatal to the enterprise, I favor some economies because I want to fly.

AF will be savaged for deferring the Probes out and in, and the sidestick will make some designers blush with embarrassment. There will be other things, Radar, CRM, and why don't we have AoA on the dash? AF was caught out through some theoretical ICE, Renfrow forgot his STALL bug was too high, and the Warning was not the problem he thought. The onset of 447 demise is not so different from Colgan's cause. A small deal became lethal, due a convergence of a hiccup in the "Force", with a cascade of shortcomings, each on its own not such a horrid thing.

In an unforgiving domain, get some rest, and replace the effing tubes, eh? Such a brutal outcome for being a little too human.

All the best to you Sir.....

DozyWannabe

3rd May 2012, 02:14

No problems, but I just want to make a couple of things clear.

I am not "defending" the Airbus FBW and computer philosophy. All I have ever done is explain aspects of the design and implementation that I am aware of, and occasionally this has meant refuting statements that, while part of popular myth, are either incorrect or unproven.

(And, on several occasions when my memory has failed me or I've made a false assumption, accepting correction on the subject.)

The design may come in for criticism in some respects, but because engineering is and has always been the art of compromise this is as true for Airbus as it is for any manufacturer. The only way to design an "uncrashable" airliner would be to make it completely immobile, which would fulfil the "uncrashable" part of the spec, but leave it completely useless as a mode of transportation.

I've said it before and I'll say it again - there's nothing wrong with the sidesticks or the control system designed around them when used properly. Some pilots are uncomfortable with the notion (I suspect that number is decreasing with time), but the truth is that all the sidestick design does is confront the reality that has been the case with every new airliner design since the '70s - which is that the flight controls are not connected to the surfaces and that artificial feel is not only just that - artificial - but also in itself a complex system which can be prone to failure. Be sure of what I'm saying here - I'm not saying the sidestick design is better or preferable to the yoke, I'm saying that there are positives and negatives to both approaches and that any preference is therefore both personal and subjective.

Lyman

3rd May 2012, 02:41

5X5. No problem whatever. I don't have the skill or experience to make a finding on the stick, yoke. Yoke is all I know. So I am merely curious, readily admitting the location of the SS outside the pilot does not in itself suggest anything untoward to me at all. My question rests on what the choice was, and how it was made, from an engineering, ergo, and safety standpoint(s).

I always fly with my left hand anyway, and it is not that far from where a SS would be....

It's been a slice, Doze.

PJ2

3rd May 2012, 05:35

Dozy - quick note as I'm on the road - my observation that the PF had the roll under control quite quickly comes from an examination of the roll trace trend - it exhibits increasing stability - the peaks and valleys in a smoothed trace are reducing and do so, (iirc) over a period of about 30 seconds. They certainly get out of hand later on but we're not talking about anything after the apogee. The sim exhibits this behaviour as well...a bit of "chasing the bank angles" as you have put elsewhere, occurs until you get it right - it's PIO but not in a way that leads to a loss of control, and yes, I think turbulence contributed but again, not in a way that should lead to a loss of the airplane. I think inexperience and more than a few training issues, (chain-of-command, discipline, handling, SOPs, CRM) have contributed here - your comment about back-to-basics is, of course, spot on.

PJ2

3rd May 2012, 06:37

Lyman;

Regarding the position of the sidestick, I will say this - when first checking out on the A320, (left seat, 1992), I was a bit taken aback and even mildly concerned that the "iron cross" symbol for the position of the opposite sidestick which was displayed on the PFD during takeoff, was removed at, (IIRC) 100ft RA. I thought it was a useful symbol so the other pilot would always know the position of the other sidestick. Over the years there were so few circumstances that made such knowledge necessary that I quickly got used to the symbol's absence. Also, sidestick movements are normally very small - 2, 3 degree-shifts when flying manually - the recent exhibition of sidestick-stirring in that video demonstrated precisely what NOT to do with the stick - the guy who posted it ought to be embarrassed - the airplane is subtle. The flight controls are already "busy" trying to maintain the last selected attitude - the airplane can be "flown" hands-off once the desired attitude is set...because FBW means, no input = no output and so no change in attitude, even in mild turbulence.

Here, I do not believe a yoke would have made a significant difference. The pitch attitudes displayed on the PM's PFD (and, we assume, the PF's PFD) would have/should have provided ample information regarding the attitude of the aircraft and what to do about it, (immediately!). The yoke may have made an initial difference given the visibility of its movement rearward, but almost within seconds, the results of the sidestick's half-way deflection were known to both pilots and I would have expected the PM to say "Stop! - I have control" or something to that effect. So there is possibly a cultural element at work here as well - in fact the third report comments on this but not wanting to take the airplane away even when things are coming badly off the rails is still a psychological "barrier" even though CRM has begun to tear it down.

This is about flying an airplane...C172, Viper, T38, DC8, A330, A380...here, no difference. After the stall had been deeply established, the potential for confusion increases exponentially and the possibility of recovery decreases by the same amount because there were in territory where no test pilot had ever been let alone any line pilots.

We may hope that one outcome may be increased awareness of and avoidance of stalling one's transport aircraft because those accidents on the increase over the past eight years or so.

philip2412

3rd May 2012, 11:20

from the beginning,i was mostly interessted in the human factors of this flight.
i looked at bonin not as being a pilot but as a simple human beeing.it does`nt matter ,if you are a pilot,train-or bus driver,when there is immediate danger for you or your pax,there must be a reaction at once.
in any other case,what will one do? sort things out!
imagine you`re driving in your car,there`s an unusable noise,what wil you do?
you can stop,check your car,accelerate to see if the noise changes or slow down.just to sort things out.
but what you will not do is putting the steering wheel 90% left or right and accelerete until the road cannot manage the speed of the car.
yes there are defiencies in training and manuel flying at AF but there could`nt be a training as bad in any airline worlwide that bonin could forget simple standards :sort things out ,adhere to the QRH and use CRM.
NO WAY !
we must not forget that he was still a pilot with nearly 3000 hours on the book.this was a minor UAS event.it is a characterisk of humang beings ,if you don`t know what`s going on to sort things out.
what was the thougt-model he developed in his head within a few seconds?
and most surprisingley,the pnf even when it looks like he "knew a bit better" was similar clueless what was going on,both forgot at the sane time the simpliest meassures,CRM,QRH.
this failure of two pilots at the same time is unbelieveable.
did they develope the same thought-model? why,what did they see?
some say we did`nt have the whole CVR report.
BEA made so many informations public before the final report as in any acc.inv.before so why not the whole content?
could`nt it be that they heard someting what no investigation team
heard before and is this the reason we must wait so long for the final report?

by the way AB surely condemns the day they have introduced that s/w feature

DozyWannabe

3rd May 2012, 15:45

by the way AB surely condemns the day they have introduced that s/w feature

I have a pretty strong hunch that there are (or were) similar gotchas in the stall warning systems of all modern airliners, because 99.9(rec)% of the time it's a logical assumption to make.

This is where revision of the basics comes in again, because pilots should be able to recognise the symptoms of a stall without having to rely on the warning instrument in the event that the warning instrument fails. No sales department of any manufacturer likes to talk about the possibility of their product going wrong, and with airline management coming increasingly straight out of an MBA without experience of the industry, pilots are the last line of defence and, for better or worse, have to think the unthinkable and prepare for it - because if they don't, there's a chance that no-one else bar the aircraft's designers and engineers have.

bubbers44

3rd May 2012, 20:06

A quick question, my Airbus pilot neighbor last night said their airline says their UAS checklist says 5 degrees nose up and climb power as a memory item at higher altitudes. I disagreed and said if you are at FL350 and are too heavy to climb how can you do this because airspeed goes TU? Especially in RVSM airspace.

He called me a retard and left because I would have maintained altitude with cruise power and not followed his airlines checklist. Am I missing something??? I chose not to fly the Airbus but RVSM airspace doesn't care what airplane you fly they just want separation in my opinion. Now I have two airline pilots against me so need other points of view please.

PJ2

3rd May 2012, 21:29

bubbers44;

Your neighbour's confusion over this checklist seems to be common among many Airbus and even non-Airbus pilots.

The Airbus Flight Crew Training Manual specifies that if the safety of the flight is not at immediate risk then the memorized items are NOT to be followed. Instead, the aircraft is to be leveled off for troubleshooting once above the MSA or circuit altitude, which FL350 certainly is.

"Immediate Risk" is not specified in the checklist but it is specified in the training associated with this checklist in an Airbus document which I posted the link to some time ago.

I have maintained for a very long time that it is this confusion and some recent low-level training (UAS event right after takeoff) that triggered AF447's PF to increase the pitch attitude of the aircraft because it was the only thing he could recall in this confusing and poorly-designed memorized drill and checklist.

The series of "if-then" statements in the memorized items do not apply to cruise altitude events where the safety of the flight is not at immediate risk. The loss of airspeed information is not an emergency and it is not a high-risk event which demands immediate action. Your response is precisely the one that should have occurred on AF447 - maintain level flight through pitch and retain the power settings which existed just before the event, while the PM gets out the QRH to fine-tune the pitch and power settings. In other words, do nothing with the pitch and power if they were suitable prior to the event. Things aren't going to change that much while the QRH is retrieved and read.

You argue correctly with your Airbus pilot neighbour but it is not his fault that he is confused, and, I submit, this and the low-level training the PM and PF had recently received are factors in this accident. How much is for the BEA to determine but I believe at least one pilot, the PF, was psychologically "primed" by the low-level UAS event which is the only UAS event training he had received.

In re RVSM, one does what one must do in an emergency of course but a thousand feet is nothing for the airplane to gain or lose so I think your point is a very good one to consider.

All that occurred after the apogee of the pitch-up and stall are far beyond transport pilot experience and territory and it is questionable whether anyone could sort out what this crew faced, after the AoA had exceeded 30deg in the "flat-plate" descent.

I have discussed this at length on all these threads, with graphics if you wish to examine this further.

Over the past year or two others here have disagreed with this assessment, and stated that above FL100, a 5-degree pitch-up is required by the UAS memorized drill regardless of altitude.

While I heartily disagree, (primarily because I think the FL100 case caters to high altitude airports and not 10,000ft above the local ground where the safety of the flight is not likely threatened by a UAS event, and a pitch of 15deg at, say, Bogota risks losing energy for obvious reasons whereas 5-deg is certainly safe enough in the initial climb until above the local MSA), the airplane will not suffer a swift and severe loss of airspeed in a 5-deg pitch-up, (I once said it would but was wrong), with an added 2.5deg pitch to the cruise pitch attitude of about 2.5deg, although it will slowly lose energy/airspeed.

But the FCTM specifically states that when/if the memorized items are accomplished by the crew, a very quick response using the QRH pitch and power settings is required to prevent an overspeed.

There is the admonition/warning to the crew in the FCTM and the schematic diagram therein which illustrates how to do this drill and checklist, to always respect the stall warning in a UAS condition.

Your Airbus pilot neighbour is wrong in his views on how to handle this event. One simply does not de-stabilize an airplane at cruise altitude without very good reason, (such as avoiding a greater danger). Pitch and power were suitable prior to a UAS event and should serve perfectly well for the few moments it takes to get out the QRH tables to fine-tune these settings. It is essentially a non-event. It may be disturbing but that is why we are thoroughly trained every six months or so...to reduce surprise and the degradation of cockpit discipline and the forgetting of SOPs.

bubbers44

3rd May 2012, 22:01

Thank you PJ2, maintain altitude and do not fly through other flight altitudes. UAS can easily be controlled by staying level and using cruise power for where you are. Thanks for the response.

Clandestino

3rd May 2012, 22:58

Am I missing something???

Both of you are missing the basic aerodynamic fact that either procedure will result in aeroplane that is flying, not stalling! Of course it's far better to maintain the known cruise pitch and power, caveat is "known". If it is not known, 5° ANU with climb power is safe attitude+power for almost any aeroplane (exception being high powered, low mach limited designs, not in production anymore). Collision risk does come into play with memory items, yet chances of having mid-air have to be weighted against chances of losing control. No extra points for guessing which is more likely to occur when ADCs go nutty.

some recent low-level training (UAS event right after takeoff) that triggered AF447's PF to increase the pitch attitude of the aircraft because it was the only thing he could recall in this confusing and poorly-designed memorized drill and checklist. I don't think so. He reduced pitch when warned by CM1, then pulled hard when stall warning went off. Nothing suggests trying to achieve any target pitch or any rational procedure at all. IMHO, it was sheer panic that doomed the flight, like the one Richard Bach wrote about:

Certainly there are hundreds of pilots who fly without fear through black nights and over miles of fog, but their peace comes not from knowing and control, it comes from the blind faith in the crate of metal parts that is an engine. Their fear is not overcome, it has simply been masked by the sound of that power plant. When that sound fails in flight, I give you fear, stronger than ever. it is not legality or guarantee that determines our safety, but how well we can fly. Methinks FMS/autopilot/ADC failure can have the same effect on the airline pilot who doesn't know his aeroplane and doesn't feel confident he can control her when times get rough as the engine failure has on the pilot of piston single on night cross-country. However, as a lot of crews made it unscathed through similar ordeal to AF447's I am not so pessimistic to suspect the malaise is widespread. Also I still maintain that middle of the WoCL significantly affected the crew's performance for the worse. There's not enough data in preliminary reports to conclude whether the crewmembers were underperforming before the accident flight.

We don't have FCTMs (or A330s, for that matter) yet we recently had a hairy situation where relevant chapters of AFM and AOM differed. Our CAA's ruling was very quick: since AOM is recognized as OM-B, it should be followed when discrepancies with other manuals arise. Was AF FCTM part of OM-D?

TTex600

4th May 2012, 01:21

The Airbus Flight Crew Training Manual specifies that if the safety of the flight is not at immediate risk then the memorized items are NOT to be followed. Instead, the aircraft is to be leveled off for troubleshooting once above the MSA or circuit altitude, which FL350 certainly is.

"Immediate Risk" is not specified in the checklist but it is specified in the training associated with this checklist in an Airbus document which I posted the link to some time ago.

Agreed, here's my COM section. Sorry for the formatting I'm on an iPad.

Message: N/A
Condition: Unreliable airspeed indications caused by pitot/static probe obstruction or radome damage.

MEMORY ITEMS - if safe conduct of flight is affected: Note: Respect all stall warnings if in ALTERNATE LAW.
1. AUTOPILOT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OFF
2. FLIGHT DIRECTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .OFF
3. AUTOTHRUST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OFF
4. Adjust Pitch/Thrust: - Below THR RED ALT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15°/TOGA - Above THR RED ALT and below 10,000' . . . . . . . . . . . . . . . 10°/CLB - Above THR RED ALT and above 10,000'. . . . . . . . . . . . . . . 5°/CLB 5. FLAPS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Maintain current CONFIG
6. SPEEDBRAKES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Check retracted
7. GEAR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .UP

When at or above MSA or circuit altitude, level off for troubleshooting.
Continued....

The way I read it, "level off for troubleshooting" means level off. It doesn't mean double your cruise pitch and apply climb power.

CONF iture

4th May 2012, 02:30

Over the years there were so few circumstances that made such knowledge necessary that I quickly got used to the symbol's absence.
You are using here the right term : We get used to be deprived of a valuable source of data … How is it better ?
It is for those few circumstances that the information is useful and necessary … but missing.
Usually, that information is most useful for the rotation and the flare, but AF447 now demonstrates how it is also valuable at FL350.

The yoke may have made an initial difference given the visibility of its movement rearward, but almost within seconds, the results of the sidestick's half-way deflection were known to both pilots
Again, why wait for the final result when the initial action is immediate and first class information for a PNF to better appreciate why the result is undesirable. How is it better for a concept to suppress such source of meaningful information ?

I was a bit taken aback and even mildly concerned that the "iron cross" symbol for the position of the opposite sidestick which was displayed on the PFD during takeoff, was removed at, (IIRC) 100ft RA.
I have not known that time, but in 98 the iron cross was already removed as soon as there was no weight on wheels anymore. Lately, as iceman50 made me realize (http://www.pprune.org/tech-log/466259-af447-final-crew-conversation-thread-no-1-a-29.html#post6780600), that indicator is now removed as soon there is no weight on the nose wheel anymore.
Everything indicates that it is not a tool they want the PNF to use to check the way the PF manipulates its sidestick. Actually Airbus thinks as absolutely useless for the PNF to know how the PF is doing its flight control commands ... In an attempt to justify the concept, the Airbus chief pilot himself has to refute the critics but his explanation simply does not make any sense. (Time 48:00 in the video)

Vol AF 447 Crash: 01/06/09: Les Raisons D'un Crash (Reconstitution) - YouTube

bubbers44

4th May 2012, 03:16

So I will as always set cruise power and about 2.5 degrees nose up and get out a checklist. With no airspeed that altimiter will keep you just fine until AS pops back again. No worries on falling out of the sky.

PJ2

4th May 2012, 04:34

Clandestino;

With regard to "missing a basic aerodynamic fact", no, I don't think either of us are missing that point. It should be quite obvious that both procedures keep the airplane flying - that is the entire point of the discussion and doesn't need re-stating.

The FCTM is a guide and an expansion upon the AOM. That fact is made abundantly clear and it should be abundantly clear to operating crews that the AOM is the legal document as specified in a carrier's OC.

The reference to the FCTM is made because, first the FCTM expands on many operating and abnormal matters and is available, and second because it explains how the UAS drill and the ADR Disagree checklists are to be done, which has proven a point of contention and confusion.

There is some value in such information given the fact that almost everyone including the BEA in their press conference was of the opinion that initially setting 5deg was the correct way to perform the memory items. It is not. But setting 5deg does no harm unless it is kept for an extended period of time - clearly, both keep the airplane flying.

Regarding theories of why the PF pitched the aircraft up, I have stated that there are a number of plausible theories and this is one. We will see what the BEA has to say and even then that likely will not be conclusive. We simply do not know why.

CONF iture, thanks for the link to the video - I'll view when able - back on the road. Clearly however, Airbus thinks that it isn't useful otherwise they would enhance it, not remove it.

Clandestino

4th May 2012, 06:47

Sorry PJ2, under "both of you" I meant bubber44's Airbus flying friend that he had argument with, not you. I should have been more specific.

DozyWannabe

4th May 2012, 14:47

CONF, with all due respect that's a narrow way of looking at things.

Beginning with the "iron cross" indicator, an alternative to your "don't want the PNF to see what the PF is doing" could be expressed as a desire to avoid visual distractions from the primary instruments during a crucial phase of flight. As many have pointed out, the ADI is perfectly capable of showing the aircraft's response to inputs.

I'd imagine in fact, that before changing the sidestick indicator removal from 100ft RA to weight-on-wheels, they canvassed pilots to find out how many of them were using the indicator after rotation and found most weren't. The indicator itself was only ever intended to be a method for cross-checking control movement during pre-flight and taxi as far as I know.

We've done this dance for years, you and I - I'm aware of your position and understand it, although I've never been 100% sure of your motives or agenda. As I said to Lyman, I'm not advocating sidestick over yoke - both have pros and cons, even for pilots. There are hypotheticals which favour yokes (which you've already pointed out), and there are hypotheticals which favour non-connected sidesticks (including artificial feel unit failure and incapacitation scenarios in which the incapacitated pilot is restricting yoke movement - how do you get their yoke free in a two-pilot aircraft without leaving your seat and letting go of your yoke?).

Aviation will progress one way or the other, and some aviators will be resistant to change - the Wright Brothers considered aileron panels inferior to their wing-warping technique, many pilots resisted the introduction of the autopilot and CVR and many were concerned about the introduction of widebodies which relied entirely on hydraulics with no cable backup (notwithstanding the fact that cable backup was impossible with flight surfaces the size of those on the 747, L-1011 and DC-10).

Airbus's electronic sidestick design was no different in that respect, however over the years its reliability has been proven and the chorus of dissent has lessened. The simple truth is that preference for one over the other is personal and subjective, just as I said to Lyman.

Sidestick aside, some target Airbus because they feel that the introduction of advanced computer technology and advance of automation has led to the atrophy of manual handling skills - maybe it has, but Airbus aren't the only ones following that path. In fact there was a greater advance in computer control and automation technology between the 727 and 757 than there was between the 757 and A320. I suspect Boeing would have done away with the cable backup in the 737NG but for the fact that it would put the "grandfathering" certification clause in jeopardy.

Things move on. Both Airbus and Boeing have proven their designs as successful, reliable and safe - the fact that they've both stuck to their guns means that pilots have a choice. One thing that's always puzzled me is that despite your distrust for the Airbus design, you still fly the type. I don't know who you fly for, but I feel sure that they or others you're well-qualified for have yoke-equipped types. If you feel the design is a detriment to safety, why do you go to work in it every day?

Organfreak

4th May 2012, 15:18

@Dozy
We've done this dance for years, you and I - I'm aware of your position and understand it, although I've never been 100% sure of your motives or agenda. As I said to Lyman, I'm not advocating sidestick over yoke - both have pros and cons, even for pilots. There are hypotheticals which favour yokes (which you've already pointed out), and there are hypotheticals which favour non-connected sidesticks (including artificial feel unit failure and incapacitation scenarios in which the incapacitated pilot is restricting yoke movement - how do you get their yoke free in a two-pilot aircraft without leaving your seat and letting go of your yoke?).

While I do favor real yokes as a little extra safety insurance, notwithstanding those Boeing crashes where they didn't save the day, I find myself defending "joy sticks" in the case of your example. In answer to your rhetorical question above, I have to say, just push the override button! You prolly just forgot for a moment. :8

Why do you insist that CONF has "motives" or an "agenda?" My take is that he's truly concerned with safety above defending any one system; not such a bad thing, is it? Subtle imputation, dear me, that's not so nice.....

Organfreak

4th May 2012, 15:22

P.S. The sidestick's only good reason for being is that it saves money (reduced weight), plus the benefit of having a clear dashboard. The industry has always maintained that cost vs./safety is an equation that needs to be balanced. I, for one, feel that's just wrong. Cost should never trump safety. :=

jcjeant

4th May 2012, 15:41

As many have pointed out, the ADI is perfectly capable of showing the aircraft's response to inputs. This is not the problem .. nobody tell the contrary
The problem is to see the position of the stick
The ADI may well show an attitude of descent while the stick is in position to climb
The ADI don't show the stick position
You will (suppose) know his position after the aircraft response on the command (visually on the ADI)
Sometime (if wrong command by the stick) it's too late for counter command

Lyman

4th May 2012, 16:05

Let's be specific. 447 shows us some very pertinent data. The SS is the heart of the life and death of this flight, agree? For three years, this thread has made abundantly clear that the two pilots were not a team, and PF tells, "I have been pulling back for some while"....

Inarguable. So let's look a bit further. The very device that could have saved the flight, did it in.

Moving the controls apart in the cockpit, from the front to the side, ISOLATED each stick from the other. (See Lufthansa, Tip Strike), To the extent that the Stick cannot be recognized by the partner/Pilot, sufficient to show the command, the aircraft is operating SINGLE PILOT. This is unacceptable. As jcjeant and CONFiture show, a belated display to show controls results is not best practice.

Explain, apologize, distract, insult, the truth cannot be hidden. Part of the direct cause of the crash involved a lack of proper brief of the Captain. When told to "Climb", PF says "I have been...." A critical and obvious 'brief' is the position of the controls, stop. It also requires no time to discuss, if visible to others.

I submit and suggest that the confusion that developed in the cockpit had more to do with the lack of visibility of the SS's than any other factor. And Confusion in the teeth of surprise is, obviously, in this case, Fatal......

Organfreak

4th May 2012, 16:17

Lyman said:
Moving the controls apart in the cockpit, from the front to the side, ISOLATED each stick from the other. (See Lufthansa, Tip Strike)

From Flight Global re:LH044:
Flight-data recorder information shows that, in the final moments of the approach, both pilots were applying sidestick input. A320 aircraft are able to accept dual input the inputs from the two sidesticks are numerically summed.

At a height of 75ft (25m) the aircraft began to drift to the left, and the co-pilot moved the sidestick 10e_SDgr right, while at 50ft the sidestick was moved left accompanied by a 28e_SDgr left-rudder input. The captain gave 4.5e_SDgr right-hand input to his sidestick at 15ft, and the co-pilot also moved her sidestick from left to right.

The aircraft banked 4e_SDgr left, touching down briefly with the left main landing-gear, before the roll angle increased to 23e_SDgr left and the wing-tip struck the runway.

I sez: This is scary stuff. I'm not going.

DozyWannabe

4th May 2012, 16:24

In answer to your rhetorical question above, I have to say, just push the override button! You prolly just forgot for a moment.

As far as I know, there's no override button on a mechanically-connected yoke, otherwise EgyptAir 990 would have had a happier ending.

There may be one on the T7's software-driven yokes, but I don't know.

My take is that he's truly concerned with safety above defending any one system; not such a bad thing, is it? Subtle imputation, dear me, that's not so nice.....

As I said, we've been doing this dance for *years* - some time before you joined, at any rate. He's moderated his tone over time, but it always seems to come back to Habsheim, Asseline and Jacquet with him - as if he wants Airbus to be discredited as payback for the destruction of the careers of those two pilots.

P.S. The sidestick's only good reason for being is that it saves money (reduced weight), plus the benefit of having a clear dashboard.

That's your opinion and you're entitled to it, however there's more to it than that - a lot more. Airbus decided it was worth a punt and went for it, and the design has proven itself as safe as any other - as I said, there are benefits and drawbacks to both approaches.

The problem is to see the position of the stick

How often is that really necessary though? To my mind there's only one incident where it might have helped (the aforementioned LH incident). In that incident, the landing conditions were marginal and the F/O should not really have been attempting the landing. The Captain broke procedure by snatching the stick without first overriding it.

The ADI may well show an attitude of descent while the stick is in position to climb

Well yes, if you're levelling off after a descent...

Sometime (if wrong command by the stick) it's too late for counter command

Very, very rarely. These are airliners, not fighters - and as such even full deflection commands a relatively slow rate most of the time. If the PF's actions are doubtful then you can lock them out for a time with the override switch, whereas with a yoke you have to physically overcome the force they're exerting.

Again, benefits and drawbacks to both approaches.

the aircraft is operating SINGLE PILOT. This is unacceptable.

No, it's standard airline practice. One pilot in control, the other monitoring - switching roles as and when necessary. The only time you need two pilots pulling is in the case of a cable-driven flight control system to get extra force on the surfaces - no modern airliner bar the 737 has cable connection to the yoke.

The problem with 447 was not confusion over the sidesticks, it was because on the two occasions the PNF took control, the PF continued making inputs on the sidestick, despite having acknowledged handing control over. The PNF should have seen the "DUAL INPUT" warning and could have held the override down to lock the PF out, but he did not.

Organfreak

4th May 2012, 16:45

@DW:
As far as I know, there's no override button on a mechanically-connected yoke, otherwise EgyptAir 990 would have had a happier ending.

I apologize for misunderstanding your example. I read it as a point against SS. Rereading, I see that you were talking about yokes. Never mind, I'll be quiet now.

Lyman

4th May 2012, 17:00

@Dozy....Quote:

Originally Posted by jcjeant
"The problem is to see the position of the stick......."

How often is that really necessary though? To my mind there's only one incident where it might have helped (the aforementioned LH incident). In that incident, the landing conditions were marginal and the F/O should not really have been attempting the landing. The Captain broke procedure by snatching the stick without first overriding it.

It is not acceptable to ignore an unsafe condition by asking a rhetorical question? "How often is that really necessary, though?"

I submit the Captain in Lufthansa incident was responding to a result of input, not a controls condition...ipso facto, your argument does not apply. Had he seen her 'wheel' command a bank radically to the right, he would have had a time advantage, and been able to avoid a 200kEuro repair.....

Throughout the CVR, and I mean no disrespect to the unfortunate souls on board, well, I'd post Abbott and Costello's "Who's on first?". Substantially, if not wholly, the confusion re: "climb, not climb, down not down, UP, no down, ok not down," was exacerbated by the lack of understanding v/v the SS, either/or or both. The 'handoffs' problem was collateral, and after the fact.....

DozyWannabe

4th May 2012, 17:12

Lyman, there are myriad potential unsafe conditions arising from connected yokes (e.g. EgyptAir 990), as well as several accidents where yoke position was not noted.

I'm not saying one is better or worse than the other, I'm saying that they are *both* valid designs.

The LH incident was a failure of procedure. The Captain should have been performing the landing in crosswinds of that magnitude in the first place. The Captain allowing the F/O to continue was a questionable command decision (as was AF447's CDB placing F/O Bonin in charge with doubtful weather ahead and a known icing problem on that type, but I digress), and he then compounded it by mishandling taking control.

With a yoke, the LH Captain would have had to fight the control forces his F/O was making, to which her reaction could have been to pull harder in the opposite direction. On top of that, dual yoke input may not do what you think. There's a school of thought on EgyptAir 990 which has the forward yoke command of the F/O and the rearward yoke command of the Captain causing the elevators to split (one up, one down), causing instant loss of control.

Again, the PNF on AF447 had the tools right in front of him to not only take control, but to lock the PF out for a period if necessary - tools put there by Airbus specifically to ensure safe operation of the aircraft if one of the pilots is not performing correctly. He did not use these tools - why?

Lyman

4th May 2012, 17:38

"The LH incident was a failure of procedure. The Captain should have been performing the landing in crosswinds of that magnitude in the first place. The Captain allowing the F/O to continue was a questionable command decision (as was AF447's CDB placing F/O Bonin in charge with doubtful weather ahead and a known icing problem on that type, but I digress), and he then compounded it by mishandling taking control."

Erm....no.

1. But the F/O was landing, and not subject to your approval.

"With a yoke, the LH Captain would have had to fight the control forces his F/O was making, to which her reaction could have been to pull harder in the opposite direction. On top of that, dual yoke input may not do what you think. There's a school of thought on EgyptAir 990 which has the forward yoke command of the F/O and the rearward yoke command of the Captain causing the elevators to split (one up, one down), causing instant loss of control."

2. Fight? NO. The F/O removes her hands immediately when the Captain even touches his wheel. She won't even wait for "My aircraft".

3. It was the additive controls due to lack of command isolation that caused Lufthansa to strike the concrete with her sharklet. Again, Captain says... and takes, she drops. (With yokes). No cross command possible.

@Dozy..."Again, the PNF on AF447 had the tools right in front of him to not only take control, but to lock the PF out for a period if necessary - tools put there by Airbus specifically to ensure safe operation of the aircraft if one of the pilots is not performing correctly. He did not use these tools - why?

The BEA will tell us why... but let me anticipate. Command confusion due to one or more of several causes. PNF does not assuredly trust his displays, so to take command, he felt his evidence for doing so was questionable. Culture in Air France puts pressure on ego, and shame, just like Korea. It is very stressful for both people to change the command. Did we hear the Captain attempting to apportion command (control)? NO, and he is the Commander de vol. So Captain himself does not see a problem with PF's performance beyond some obvious corrections, Rudder Bar coming to mind. Captain notes PF "I have no VS..." and says, get this...."Ok"... "He's pulling UP...." "Well someone should, we're at 4000 feet"......Remember, the Captain enters and says "What the Hell are you doing?.....

PJ2

4th May 2012, 17:42

Ah, I see - no worries. I hope bubbers44' neighbour is open-minded and willing to learn a bit.

I'm interested in your note regarding the FCTM.

First, I know that each airline determines for itself, within applicable limits, how it will operate a manufacturer's aircraft. A few decades ago, we used to re-write the manuals entirely and heaven help someone who transitioned from one airline to another. Today, most airlines adopt the Boeing and/or Airbus ramp-to-ramp SOPs with type-specific modifications.

The FCTM is, as you say, more a resource than a manual and any disagreement between the AOM and other manuals is resolved in favour of the AOM. First such manual I saw was for the B727 around 1983. We've used a type of FCTM for years - the present Airbus one is a very helpful document. As you would know, it can be supplied by the manufacturer, earlier, moreso from Airbus than Boeing, and then modified to accommodate airline-specific procedures. The ones I've seen are very close in their presentations and procedures. The present response to the UAS showed up in about 2007, with the flow-schematic which included the 'do not do the memory items' qualification. IIRC I posted an image of the flow-chart.

DozyWannabe

4th May 2012, 17:51

2. Fight? NO. The F/O removes her hands immediately when the Captain even touches his wheel. She won't even wait for "My aircraft".

You sound awfully sure. This sounds an awful lot like the unprovable "no pilot would ever..." assertion. Where's your proof?

3. It was the additive controls due to lack of command isolation that caused Lufthansa to strike the concrete with her sharklet. Again, Captain says... and takes, she drops. (With yokes). No cross command possible.

The tools to isolate command were there with the sidesticks, even if she held on (Captain presses and holds the override button). Why weren't they used?

Come on Lyman, this is whataboutery and prejudice - I expect better.

PJ2

4th May 2012, 17:54

O.F.;
Cost should never trump safety.
No, it shouldn't.

But it does, mainly because most of the time such a decision is made (commercial versus safety priorities) the circumstances are complex, there are many factors pulling the decision-makers in both directions and on any one day, it is possible, given history, experience, competency, either decision could be, in the moment, the correct one.

I know of at least three A320 heavy landings which exceeded the certification limits in which the airplane flew again, right away. I know at least one was a commercial decision until Airbus got hold of the data and grounded the airplane. Often it isn't nearly as clear-cut and airlines have significant challenges today with horribly low fares and therefore precious little money with which to "do the right thing". The industry is so far retaining its enviable safety record and that says something about successful decision-making and cost-cutting. But the phrase, "Fine-tuning the Odds Until Something Breaks", was the title of a paper written by William Starbuck on the Challenger accident. Great title, great point. And Diane Vaughn has written a superb book entitled, "The Challenger Launch Decision" - an excellent examination of the organizational culture and the "normalization of deviance" at NASA which led to the first, and many agree, the second shuttle.

I think the same thing applies today and it takes awareness of these factors and strong leadership to cut costs at an airline and remain as safe as possible. It isn't black-and-white.

Lyman

4th May 2012, 17:58

Dozy, you are the whatabouteryiste here. What I describe is the procedure with yokes at all times, without exception. "My aircraft" is based on many things, but always includes a peep at the controls.

You have ignored the time advantage in visible controls, if the PF is maneuvering incorrectly, the Captain (Lufthansa) does exactly what I describe, if in an a/c with visisble controls. I don't have to guess, and you saying that Captain would have a tug 'o War with F/O in a yoked airplane is absurd.

Lyman

4th May 2012, 18:00

In support of PJ2, above, I would offer the deferred (illegally) and pencil whipped skin inspex on Southwest's 737's, and don't let's forget Aloha.....

PJ2

4th May 2012, 18:27

Lyman - yep, that, and a whole lot of other things I personally witnessed during my flight data work. Thing is, I never understood why they perceived flight data as "just an opinion" that could be dismissed when inconvenient.

Further to the point and further off-topic, this came out today:

WASHINGTON (AP) - Federal officials are seeking $655,125 in fines against Alaska Airlines and its Horizon Air affiliate for alleged safety violations, including failing to inspect a plane for cracks.

Sponsored LinksThe Federal Aviation Administration said Thursday that Horizon operated a Bombardier Dash-8-400 aircraft on 45 flights, while it failed to follow a safety order to check for cracked or corroded fittings on the engine housing.

A 2011 order required airlines to inspect the fittings every 300 hours of flight time and make repairs as needed. The FAA said Horizon used the plane on at least 45 passenger flights in March 2011 after it had passed the 300-hour mark.

The FAA proposed a civil penalty of $445,125 against Horizon.

The FAA also said it would seek a $210,000 civil penalty against Alaska Airlines, charging that the airline failed to properly tag turned-off equipment before making repairs to Boeing 737 jets. It said the violations of worker-safety rules occurred 10 times in 2010 and 2011.

Both airlines are owned by Seattle-based Alaska Air Group Inc.
Company spokeswoman Bobbie Egan said Horizon performed the required inspection of the fitting over the engine covering, "however, we did not properly document our maintenance due to a misunderstanding over wording on the work order." She said the plane was pulled from service the next day after the documentation mistake was spotted, was inspected again and passed.

Egan added that Horizon is replacing the fittings with ones that don't require such frequent inspections.

On the Alaska planes, she said, the maintenance work was done to Boeing's specifications but not properly documented. She said passengers were never in danger.

The airlines have 30 days to respond to the FAA

DozyWannabe

4th May 2012, 18:57

Dozy, you are the whatabouteryiste here. What I describe is the procedure with yokes at all times, without exception.

I'd say EgyptAir 990 is a bl**dy big exception!

You have ignored the time advantage in visible controls

I haven't - CONF made the point earlier, and I acknowledged that he made the point. All I did was provide a counterpoint.

I don't have to guess, and you saying that Captain would have a tug 'o War with F/O in a yoked airplane is absurd.

Again, EgyptAir 990 along with many other incidents over the years proves that what should happen is not necessarily what does happen.

@PJ2 :

Flippin' 'eck! You'd have thought Alaska would be the last airline to let those kind of shenanigans happen again after the drubbing they got over Alaska 261...

Lyman

4th May 2012, 19:55

Egan added that Horizon is replacing the fittings with ones that don't require such frequent inspections.

Anybody here ever notice an operator seeking applause after the fact, for what needed to be done as part of their work, before the fact?

Dozy, stop with the coy... You try to consistently conflate irrelevance with procedures....

DozyWannabe

4th May 2012, 20:23

Please elaborate. As far as I know, you stated that without exception, a junior PF will relinquish control to a senior PNF as soon as the latter's hand touches the controls, to which I expressed doubt.

You also stated that there would never be a "tug-of-war" on the yoke. I simply provided one example (and looked up some others, made some notes) of where that was precisely what happened.

Prior to that I stated that the Airbus flight deck provides a way of locking out a wayward PF that is impossible with connected yokes - but for whatever reason on two ocasions where it would have been helpful, it wasn't used.

I've already said that CONF makes good points about tactile response being a positive aspect of the yoke design, and provided examples of where the sidestick arrangement has positives over the yoke from a safety/piloting perspective.

I've stated categorically that I don't consider one better than the other, and that both have benefits and drawbacks.

Tell me where I'm going wrong here, because I can't see it.

PJ2

4th May 2012, 20:32

Dozy;
You'd have thought Alaska would be the last airline to let those kind of shenanigans happen again after the drubbing they got over Alaska 261...
I agree. I recall that there was at least one suicide over the outfall of 261.

Clearly here, money has a longer shadow than memory of how and why things went wrong.

The problem with constant change at the top is that memory disappears with people who have moved on but the pressure for profit is inherited but without the history. The usual obvious "solutions" are invoked.

You not only have to come clean you have to be clean to start with but the problems are not sourced nor resident in individual airlines. The same sources that are now being discussed in the popular press regarding families under enormous financial stress (sometimes resulting in violence) are not that different from the financial forces that cause ordinarily rational people to compromise their own long-held professional or management values especially if one's job is on the line due to performance pressures. Standards cost, one way or another.

PJ2

Lyman

4th May 2012, 21:39

You have a habit of oscillating between big picture, small picture, and enlisting absolutes if necessary to distract from a currently well framed discussion. We were discussing 447, and Lufty/Hamburg. Up jumps Egypt, and Lyman is in the weeds.

Simples. LH Captain/F/O dynamic with yokes: "Fräulein, Geben sie mir"
"Naturlich, Kaptain"...... Sharklet remains virgin. Ja?

Because her yoke is visible, the commander acts quickly, and there is no cross command, IMHO.

They hadn't jihadists aboard, and the Captain was not wearing an hatchet handle out his skull, nicht wahr?

Klaar?

mm43

4th May 2012, 21:44

This ongoing Yoke v SS argument is IMHO not relevant to the loss of AF447. Why? Because in this case other factors were at work, i.e.

Lack of CRM,
Lack of communication,
Lack of knowledge,
Lack of relevant training, and
Failure to follow SOPs.

Yes, it may have helped the situation if the SS position was being displayed on the PFDs, but it wasn't and with all the other problems just listed, there is no guarantee that the outcome would have been much different. To give Capt Dubois some credit, I suspect that if he had seen the SS position floating up high on the overly blue PFDs on his return to the cockpit, in all probability he would have regained the LHS and done something about it.

I raised the issue of the "Iron Cross" displaying when in ground mode, and the possibility of it being displayed in flight mode when the A/P is disconnected in AF447 Thread No.3 (http://www.pprune.org/tech-log/452836-af447-thread-no-3-a-76.html#post6497401). CON fiture disagreed at the time, but if it were displayed, it would certainly identify the "mayonnaise makers" whether SIM borne or airborne.

My only other suggestion is that the color of the cross change to orange for dual inputs and to red if priority control has been taken.

Lyman

4th May 2012, 21:48

Hmmm.... Not relevant? Not contributory in any way shape or form?

That is quite a relief.

Done then, with the SS issue. No complaints.

, I suspect that if he had seen the SS position floating up high on the overly blue PFDs on his return to the cockpit, in all probability he would have regained the LHS and done something about it.

He didn't have to, he had just climbed an aisle canted at 16 degrees, uphill...

mm43. What color if mayonnaise? (rate)

:ok:

DozyWannabe

4th May 2012, 22:09

We were discussing 447, and Lufty/Hamburg.

Which highlight shortcomings in the Airbus sidestick system when used improperly...

Up jumps Egypt

Which highlights shortcomings with connected yokes...

and Lyman is in the weeds.

So you only want to talk about things that the sidestick detractors agree with. With you. I respectfully decline.

Simples. LH Captain/F/O dynamic with yokes: "Fräulein, Geben sie mir"
"Naturlich, Kaptain"...... Sharklet remains virgin. Ja?

It would have worked the same if the override system had been used properly with sidesticks. The issue is using the tools to hand *correctly*. Done properly with the sidestick or yoke system, there'd have been no issue. The problem was that the system was used incorrectly, and could have been used incorrectly no matter what the control method.

Because her yoke is visible, the commander acts quickly, and there is no cross command, IMHO.

Opinion yes. It's not a certainty.

They hadn't jihadists aboard

El-Batouti was no jihadist - he was a man with financial problems who'd just been disqualified from transatlantic routes.

mm43 - I agree absolutely it's irrelevant here, but sadly we're at that point on the hamster wheel again.

I disagree that having the SS position indicator on the PFD would help particularly though. The reason I disagree is because there have been too many incidents where the yoke position has been ignored during a pressure situation - I really don't think it's as big a deal as some make it out to be. The Captain of AF447 didn't put the evidence of roll and pitch instability plus a rapidly unwinding altimeter together in time, so all a position indicator would likely have done would be to have contributed to information overload. Besides, in the A320 sim, standing over the centre console I could see enough of the sidesticks to judge position to some degree - and I'm not a tall guy!

Based on what I know I can only conclude that sidestick position is a red herring here. The PNF could have locked the PF out at any point and didn't - he seemed unsure as to whether he had the authority to do so and was waiting for the Captain. When he arrived, the Captain's first action was to take the troubleshooting phase back to square one, which cost them more time than they had. Judging by the CVR, the PNF had a handle on what was wrong from the outset and consistently showed better judgment than the PF. Unfortunately, for whatever reason, he lacked the confidence to act directly on what he believed to be the best course of action.

mm43

4th May 2012, 22:11

LymanWhat color if mayonnaise? (rate)Purple! :E

Lyman

4th May 2012, 22:16

Mais non. Blanc. :p

mm43

4th May 2012, 22:24

DozyWannabe...the PNF had a handle on what was wrong from the outset .... for whatever reason, he lacked the confidence to act directly on what he believed to be the best course of actionNeither did he have the "b:mad:lls" to appraise Dubois on what had happened in the past 1 - 2 minutes.:(

DozyWannabe

4th May 2012, 22:32

Exactly - that worries me far more than the sidestick or automation debate.

Lyman

4th May 2012, 22:42

...the PNF had a handle on what was wrong from the outset .... for whatever reason, he lacked the confidence to act directly on what he believed to be the best course of action......

mm43.....
Neither did he have the "blls" to appraise Dubois on what had happened in the past 1 - 2 minutes.

Both you guys are confident PNF actually knew what had been happening?
See, when BEA flesh out the CVR, I think HF will take front and center. PNF may only appear to have a handle on the moment, we'll just have to see....

Doze, I really have to call bs on your comment. "...he lacked the confidence to act directly...etc." Embarrassingly presumptuous, IMO.

DozyWannabe

4th May 2012, 22:47

He told the PF to stop climbing, told him not to deploy speedbrakes and during the few seconds he had control tried to get the nose down. He seems to have figured out what was happening - why he didn't communicate this is one for the BEA HF bods.

@Lyman, I'm only going on the information in front of me. Every call he made prior to the Captain's arrival was correct, and yet he seems to have felt he had to wait for the captain rather than put his foot down and take control himself. I'm no expert, but it reads a lot like lack of confidence to me.

A33Zab

4th May 2012, 23:08

Lack of CRM,
Lack of communication,
Lack of knowledge,
Lack of relevant training, and
Failure to follow SOPs.

Exact!
I fully agree with you.:ok:

Concerning your suggestion, maybe a compromize will be acceptable for CONF?

Show the PF SS on the PNF display, so PF will not be distracted by information he already knows.
The information only shown if SS is moved from neutral so the pop up will trigger the monitoring pilot.

@Lyman:

Once the captain opened the door and sat down,
the SW ceased, all AS were gone (FPV Flags were present when he selected it) - no FD bars and ..... pitch - at that time - returned to even
negative values for approx. 1 minute.

The only clue he had visible was the boxed V/S, the unwinding ALT and very poor briefing.

jcjeant

5th May 2012, 00:00

DW
I've stated categorically that I don't consider one better than the other, and that both have benefits and drawbacks.I think everyone can agree with your analysis
After all you are not the only one to have this view
As there are disadvantages to both .. and if we want to be practical there are two choices:
Either correct the problems on the two or choose to concentrate all efforts on a single
Indeed .. in an effort to standardize it would be smarter to keep for the future a single system that would have been perfect (after the needed corrections)
Indeed .. it is possible to steer a bicycle or a motorcycle with handlebars or a steering wheel
The handlebar was chosen as standard .. and nobody would think to currently building a bike equipped with a steering wheel ....
Hope this made sens ...

DozyWannabe

5th May 2012, 00:12

Either correct the problems on the two or choose to concentrate all efforts on a single

Why? Things are working as well now as, if not better than when all airliners had yokes, are they not?

If a klutz like me can take off, land and recover from high-altitude stall in an A320 sim on my first or second attempt, then there can't be too much wrong with the setup.

If you can use Windows, you can use MacOS with no real issues. Same if you can drive with the steering wheel on the right as opposed to the left. If you can fly with a yoke you can fly with a sidestick. If both approaches work with no significant impact on safety, there's no compelling reason to standardise on one.

mm43

5th May 2012, 01:03

Originally posted by A33Zab ...

Show the PF SS on the PNF display, so PF will not be distracted by information he already knows.
The information only shown if SS is moved from neutral so the pop up will trigger the monitoring pilot.I think you are heading on the right track.:ok:

Basically a software adaption to make use of data already available.

DozyWannabe

5th May 2012, 01:15

If the PNF does not feel they have the authority to override the PF, it makes no difference if they can see the inputs or not. The F/O in the Birgenair 757 crash must have practically had the yoke in his lap and he *still* didn't take control.

The software change mm43 describes wouldn't be difficult to implement, but would it have helped? I'm not convinced.

Lyman

5th May 2012, 01:41

On the contrary, we think PF did NOT know where his SS was, relative to its own index, hence: "inadvertent aft input".

With a proper display of his own input, scratch "inadvertent".

Quote:
Originally posted by A33Zab ...

Show the PF SS on the PNF display, so PF will not be distracted by information he already knows.
The information only shown if SS is moved from neutral so the pop up will trigger the monitoring pilot.

Organfreak

5th May 2012, 02:18

The software change mm43 describes wouldn't be difficult to implement, but would it have helped? I'm not convinced.

There is no way to know if it would have, or not. But it might have. Isn't that good enough? I think so.

Lyman

5th May 2012, 02:40

Organfreak. From the comments PNF makes during run up to STALL, he is basing his chatter on the a/c attitude from displays only, not any suss of PFSS.

Does a concerned PNF want to see a SS display to confirm/mate input with response? Boy Howdy. If it had been available, he'd be on it white/rice, you betcha. Maybe this fella allergic to mayonnaise?

CONF iture

5th May 2012, 03:20

As an instructor initially and long time flying multicrew aircrafts, fully visible yokes have always tell a lot of the story, and so in silence – In relation to the aircraft behavior, timing amplitude duration and speed of displacement of the flight control command tell so much to a PNF.

Airbus thinks otherwise, therefore such direct information has gone, evaporated.
Just get used to it … Put everything on the aircraft behavior, whatever the reasons are, both internal and external.

As Lyman put it, there is tremendous confusion on AF447 about the commands, attitudes, steps that should or not be applied.
Direct visual information from yokes would have relieved big part of the questioning.

To give Capt Dubois some credit, I suspect that if he had seen the SS position floating up high on the overly blue PFDs on his return to the cockpit, in all probability he would have regained the LHS and done something about it.
That is all of an acknowledgement for someone who just wrote the ongoing Yoke v SS argument is IHHO not relevant to the loss of AF447.

mm43

5th May 2012, 03:38

Originally posted by CONF iture ...
That is all of an acknowledgement for someone who just wrote the ongoing Yoke v SS argument is IMHO not relevant to the loss of AF447Touché.;)

A330s have SS, and I doubt very much that Airbus will be looking at adopting "old" technology. More likely they make the pertinent changes to satisfy BEA recommendations - to be revealed in due course.

RetiredF4

5th May 2012, 09:21

He told the PF to stop climbing, told him not to deploy speedbrakes and during the few seconds he had control tried to get the nose down. He seems to have figured out what was happening - why he didn't communicate this is one for the BEA HF bods.

Are those few bits and pieces really enough indicators, that PNF was aware of the situation and would have been able to act in a correct way from the onset (AP ATHR disconect) of the event?

I don´t think so. PNF was out of the loop from beginning and equally surprised like PF by what exactly was happening and was way behind the events. He grasped some bits and pieces further on into the event, but again without grasping the whole picture.

That´s also the reason why he did not take over control, why he did not give clear and precise commands, why he could not get the attention of the PF, why he was not able to brief the captain in a clear and professional mannor. Poor captain got nothing out of this crew, when he returned to the flight deck.

"AP and ATHR disengaged due to UAS, Initial control problems in ALT 2 got us into a steep climb, SW triggered, we leveled off with TOGA and are now in some kind of uncontrolled descent despite TOGA and back SS. What do you recommend? "

Wouldn´t that had been some kind of appropriate information from someone who knew what´s happening?

PNF recognised early that something went wrong, but he couldn´t get to the point what exactly was going wrong, why it was going wrong and what to do about it to save the situation.

You think otherwise?
Than sit down in that left hand seat, get yourself into the loop of this flight and then write down how you would have handeled the situation from the beginning and compare it to what we know until now (the HF group may shed aditional information in the final report) what PNF really accomplished.........close to nothing.

And then the question stays, why two pilots missed that bad.

A33Zab

5th May 2012, 13:15

And then the question stays, why two pilots missed that bad

Will be answered !? soon.

BEA Press release 13 October 2011:

This is why the BEA reminds those concerned that only an in-depth
analysis of the facts will enable all the causes of the accident to be
determined. New Safety Recommendations will then be issued in
addition to the existing ones. All of this work will be included in the
Final Report that will be published by June 2012.

rudderrudderrat

5th May 2012, 14:28

Hi DozyWannabe,
If you can fly with a yoke you can fly with a side stick. If both approaches work with no significant impact on safety, there's no compelling reason to standardise on one.
The Airbus side stick system lacks the "position of the control surface feed back loop" to the pilot. We have no easy way to sense how much control surface deflection is required to satisfy our side stick input. It is very useful for an experienced crew to know.

Imagine replacing the steering wheel of your car with a side stick.
http://www.auto-ui.org/09/docs/p19-kienle.pdf
On page 21 it shows the results of various side stick control feed back loops. The only negative results are from the "spring centred force reflective" side stick (similar to Airbus s.s.). It's also interesting to note the perceived difference between experienced and non experienced drivers. (your observation in post #396)

Pilots really need to be alerted when their control surface is being deflected by an "unusually" large amount. During asymmetric flying, the deployed roll spoilers on the lower ECAM page attract one’s attention. With the aircraft in trim properly, they remain stowed. Since there is no "position relative side stick" on the Airbus (nor feed back for the side stick demand from the other pilot), we really need something similar to warn us that the elevator (or stab trim) is outside its normal range.

Lyman

5th May 2012, 14:45

This may be the salient determination of several "knocks" on the SS/aware loop.

If one does not know the position of a deflected control surface, and by extension the "actual" position of the SS, well.... "You climb", "I am climbing?"
"Climb, then..." "No, don't climb...." "Well, then, go down...." "He is climbing...:

"Someone should, we are at 4000 feet....." "Tire, Tire, Tire..." (Pull. Pull, PULL)

If PF, at his initial aft stick, then assumes his input is zeroed, he will think, "fine, oops, I need an aft stick..." Each time assuming his input is an isolated one, instead of "additive" (accumulative)..... This is affirmed due the inexplicable travel of the THS full up....

"The Airbus side stick system lacks the "position of the control surface feed back loop" to the pilot. We have no easy method to see how much control surface deflection is required to satisfy our side stick input. It is very useful for an experienced crew to know."

Ian W

5th May 2012, 15:53

Dozy
You also stated that there would never be a "tug-of-war" on the yoke. I simply provided one example (and looked up some others, made some notes) of where that was precisely what happened.

Prior to that I stated that the Airbus flight deck provides a way of locking out a wayward PF that is impossible with connected yokes - but for whatever reason on two ocasions where it would have been helpful, it wasn't used.
So if a suicidal PF is sitting in the left hand seat in a 'bus it is even easier to be successful - just press override? :rolleyes:

I think that the point that has been made several times is that had the captain of 447 re-entered a cockpit equipped with yokes, he would have seen the PF with the yoke pulled into his lap, TOGA power and the altimeter unwinding at a high rate. Without anyone speaking and without any alarms it would have been immediately apparent that the aircraft was sitting in a stall the wrong side of the drag curve.

True it should not have got to that point - but it did; and the PNF and captain seemed totally unaware of the mayonnaise being stirred by the PF so had no reason to press override.

PuraVidaTransport

5th May 2012, 16:09

For all the knowledgeable military guys, a question to help guide my opinion on side-sticks versus yokes. In duel seat trainers for aircraft such as the F-16 or F-18, does the training pilot's stick have a connection with the trainee's stick? In other words, does the training pilot know exactly what the trainee is doing with the stick or is he forced to rely only on the reactions of the plane? Be interesting to know what the military thinks on what information two-pilot airplanes need to convey without a visual reference.

NeoFit

5th May 2012, 16:13

I was searching some old data in my computer... and I have seen ...

La base de donnees WebDAS presente les informations relatives aux enquetes conduites par le BEA a la suite des accidents et incidents d'aviation civile.

Dans cette base de donnees :
Il n'y a pas incident AF mai/juin 2008 - sondes Pitot

Il n'y a pas incident AF juillet 2008 - sondes Pitot

Il n'y a pas les 3 incidents aout 2008 - sondes Pitot

Il n'y a pas les 2incidents ACA de septembre 2008 - sondes Pitot
Il n'y a pas incident AF septembre 2008 - sondes Pitot

Il n'y a pas incident AF octobre 2008 - sondes Pitot

Undoutedly, my computer seems to have lost memory

Lyman

5th May 2012, 16:40

Dozy

The evidence is yelling at you.....No one sussed the PF Stick movements....If they had,,,, etc,.etc,,,,,,

There is another even more troubling possibility....Let's say that the SS performance is "as designed", no problemo.....The Sticks were visible, the actions noted, and.....

There was no response to Recovery solutions? This is the most obvious, had the sticks been merely "one design of two, and I don't have a preference, one way or t'other....",

Something broke, something was wack, and three pilots despite their best efforts, could not recover from STALL, LOC, and jet upset. I need to suggest again that something is missing, inadvertent, or deliberate, from the data.

And the a/c was unrecoverable, as equipped.....

aguadalte

5th May 2012, 17:00

Quote:
Originally posted by A33Zab ...

Show the PF SS on the PNF display, so PF will not be distracted by information he already knows.
The information only shown if SS is moved from neutral so the pop up will trigger the monitoring pilot.
I think you are heading on the right track.http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/thumbs.gif

Basically a software adaption to make use of data already available.

Agree.
And,
What about a software change also, to prevent the aircraft to continue trimming up, below VStall?

roulishollandais

5th May 2012, 17:07

Since I have seen a number of "unmasking" events in other aircraft, and the switch to ALT2 from Normal law, opens possibilities for unmasking events,

I presume these "unmasking events" have something common with unobservability of effective aircraft ? ;)

Cubs2jets

5th May 2012, 18:41

Good God, you guys are still working this one? :ugh: I'd have thought you would have finished up the report and sent it on to the accident investigation chaps by now. :D Time to move on to more recent events. :zzz:

mm43

5th May 2012, 22:36

@ rudderrudderrat,

A graphic of the Airbus SS arrangement was posted by A33Zab in AF447 Thread No.5 (http://www.pprune.org/tech-log/456874-af-447-thread-no-5-a-12.html#post6568978).

With the addition of Synchro motors on each axis and interconnected to the opposite SS, the movement of each stick would then follow the other. Dual inputs would result in the appropriate feedback. However, realistic control surface feedback would be more complex, but if the FBW existing control surfaces positional feedback had inertial data added to it, a control transformer could be inserted into the Synchro couplings and a more realistic "feel" would be available to the sidesticks.

That's a simplistic example, and sophistication would improve it.

The disadvantage is as usual - extra complexity and weight.

OK465

6th May 2012, 00:20

What if the captain returned to the flight deck and observed a yoke held full forward?...

And generating, at best, an agonizing 2 degrees per second of nose down pitch rate?

Or a hands off neutral yoke generating absolutely no nose down pitch rate?

bubbers44

6th May 2012, 01:10

better than full up and hopefully full nose down. They didn't do that so a lot of people died. It shouldn't have happened.

OK465

6th May 2012, 01:22

B44:

when you update your experience with true FBW time, not just spoilers, get back to me. :)

bubbers44

6th May 2012, 01:29

spoilers, fbw?????

OK465

6th May 2012, 01:30

757.........

bubbers44

6th May 2012, 01:37

757 was my final airplane, I still do not get the question.

OK465

6th May 2012, 01:38

scary.......

bubbers44

6th May 2012, 01:40

bye maybe someone knows what you mean

Old Carthusian

6th May 2012, 01:51

The yoke/sidestick debate is another of those irrelevancies which crops up from time to time. The sheer number of Aibii whizzing around safely using sidesticks proves this. The question as to whether the use of a yoke would have helped is rather moot. Given the captain's possible befuddled state on entering the cockpit he could have possibly overlooked the yoke being pulled back or misinterpreted the angle so discounting the evidence. The only reliable indicator would have been the instruments (minus airspeed). We do seem to have some indication that the PF's scan had broken down and that the PNF was deriving some information from his instruments but not acting on it. A responsible captain would first of all look at the instruments not the position of a yoke - to do so would be otherwise unprofessional. The instruments would give an accurate indication of the state of the aircraft. As Dozy sensibly put it neither method of input is perfect and both have their disadvantages but the substitution of a yoke in this situation would have made no difference. A different more active PNF would have made a difference but once again human factors are the most important here.

CONF iture

6th May 2012, 03:03

Given the captain's possible befuddled state on entering the cockpit he could have possibly overlooked the yoke being pulled back or misinterpreted the angle so discounting the evidence.
Or he could have possibly realized how the picture was wrong with a yoke in the stomach at FL350.

A responsible captain would first of all look at the instruments not the position of a yoke - to do so would be otherwise unprofessional.If I had to enter that flight deck at that time, the first obvious clue would have been that full back yoke at 350 ... now call me unprofessional.

HazelNuts39

6th May 2012, 08:08

Just learned something on another thread (http://www.pprune.org/tech-log/484457-aoa-asi-low-speed-awareness.html#post7170497):
low speed awareness tapes are just alpha information superimposed on speed tapeAt first sight, this would seem to be preferable to the BUSS in an UAS situation. What are the disadvantages?

rudderrudderrat

6th May 2012, 08:52

Hi HazelNuts39,
What are the disadvantages? We have that system already. With blocked pitots and your IAS shows say 60 kts, then the superimposed stall speed is uselessly displayed off scale.

control surface deflection:
The crew of A380 VH-OQA were concerned about their roll controllability with a big fuel imbalance. At a lecture I attended, the Captain mentioned that there was no feed back through the side stick as to how much aileron was being applied. They therefore frequently looked at their flight controls system page to see how close to aileron saturation they were getting. (only inboard ailerons were working)

see pages 6-7 of http://www.atsb.gov.au/media/2888854/ao-2010-089%20preliminary%20report.pdf

"Prior to leaving the holding pattern, the crew discussed the controllability of the aircraft and conducted a number of manual handling checks at the holding speed. The crew decided that the aircraft remained controllable...As the crew started to reconfigure the aircraft for the approach by lowering flaps, they conducted further controllability checks at the approach speed and decided that the aircraft remained controllable..."

On Airbus, because the control surfaces are being moved "invisibly" (except on a systems page which may not be displayed) when the ailerons or elevator reach say half deflection, then I think there should be some alert. When the stab trim runs outside its normal range - then there should be a warning.

A33Zab

6th May 2012, 08:53

The disadvantage is as usual - extra complexity and weight.

Not as much weight and complexity as this:

787 Controls
http://i474.photobucket.com/albums/rr101/Zab999/787Yoke.jpg

Maybe IF SS feedback/interconnection was available it would not have happened.

But

IF ADR2 hadn't have been the voted median.....
IF they hadn't switch over to ADR3 (display on RH PFD)...
IF captain had returned to cockpit earlier (or never left)....
IF PF didn't overreact......
IF multiple UAS had lasted longer than 10s in the first fase....
IF they had realized what was going on....
IF training,knowledge, CRM, communication, SOPs would have been sufficient.....
IF AoA indicator was fitted (or BUSS was opted)....
IF inertials had been outside the abnormal attitude values.....

The outcome could have been different too!

Maybe the clues are in the modifications which have been adopted after this tragedy.

For systems:
- Inhibition of AP/FD reconnect after UAS.
- More rigid USE MAN PITCH TRIM PFD msg when autotrim is not available.
- F/CTL ALT LAW (PROT LOST) msg accompanied with reason what caused the transition.

IMO the installation of an AoA indicator will be mandated - in the final report - because it is already optional and provisions are available.

Old Carthusian

6th May 2012, 08:55

HazelNuts39

6th May 2012, 09:12

With blocked pitots and your IAS shows say 60 kts, then the superimposed stall speed is uselessly displayed off scale.I don't understand that it would do that. Are you sure? Please explain.

rudderrudderrat

6th May 2012, 09:33

Hi HazelNuts39,

Please see John T's explanation http://www.pprune.org/tech-log/484457-aoa-asi-low-speed-awareness-2.html.
If the stall speed is calculated as being X kts and superimposed on the speed display accordingly, but due to iced over pitots at 250kts, your IAS only shows 60 kts, then your stall speed will be off the scale at X kts. All you'll know is that you think you are below the stall speed on the IAS read out - even though you may still be at 250kts. The BUSS system (when displayed) is independent of pitots.

As far as I know, BUSS is only displayed after all 3 ADRs are turned off manually.

Hi A33Zab.

Thanks for diagram of 787 yoke system. It's definitely a lot more complicated, heavy and costly than the Airbus side sticks - but at least the control surface displacement feed back loop to both pilots is complete.

HazelNuts39

6th May 2012, 10:09

If the stall speed is calculated as being X kts and superimposed on the speed display accordingly, but due to iced over pitots at 250kts, your IAS only shows 60 kts, then your stall speed will be off the scale at X kts.Let's assume that X = 200 kts, i.e. 80% of 250. When IAS then drops to 60 kts, my understanding is the stall speed will be indicated as 48 kts (80% of 60 kts). Am I wrong?

rudderrudderrat

6th May 2012, 10:23

Hi HazelNuts39,

I think you are probably correct.
I hadn't thought through the logic of the dynamic stall margin being presented as a %age of what's displayed.

A33Zab

6th May 2012, 11:27

It's definitely a lot more complicated, heavy and costly than the Airbus side sticks - but at least the control surface displacement feed back loop to both pilots is complete.

As I recently understand from the 757/767, despite the 'interconnected' yokes, the possibily of splitted RH/LH Elevator surface control doesn't seem to be a good idea either.

May hope that the 787 FBW protects from such a situation.
How would it determine which input to follow?

rudderrudderrat

6th May 2012, 11:50

Hi A33Zab,
As I recently understand from the 757/767, despite the 'interconnected' yokes, the possibily of splitted RH/LH Elevator surface control doesn't seem to be a good idea either. I don't know if you are referring to some incident (link?) which I don't know about.
On the TriStar we could split the Capts & FO's load paths to the L & R elevators and L & R ailerons respectively, so it was technically possible to fly each side independently. They were only split if we had a control jam on one side. PFM.
How would it determine which input to follow?In that case, you'd have to do as Airbus now do - only one pilot at a time flies the plane.

DozyWannabe

6th May 2012, 14:29

I don't know if you are referring to some incident (link?) which I don't know about.

EgyptAir 990 possibly. Full forward in the RHS and full back in the LHS led to split elevators - I think Boeing changed the design after that.

In that case, you'd have to do as Airbus now do - only one pilot at a time flies the plane.

Strictly speaking I think all airliner ops are only supposed to have one pilot at a time flying the plane, are they not? You can usually spot documentaries and programmes that have done their homework versus those who haven't because the latter will have both pilots with hands on the yoke in cruise even when nothing is untoward.

I know you and others perceive the feedback loop as essential, but I'm not sure it is as essential as you believe it is when an airliner's flight surfaces are fully-hydraulic. A lot of people give Airbus a hard time on the KISS principle, but in the case of the control setup, theirs is a lot simpler than the yoke systems of other manufacturers. From an engineering standpoint there's a lot more points of failure in a backdriven feedback system than the spring-driven feel of the Airbus sidestick design.

The disadvantage is as usual - extra complexity and weight.

Not to mention some of the disadvantages of the yoke system that have already been mentioned (e.g. dual input becoming a strength contest between pilots, lack of positive override).

The short version is that for every "might have made things better", there's a "might have made things worse" - *if* you're looking at things dispassionately, and all other things being equal.

Is tactile feedback necessary or is the yoke a crutch? I feel sure I've said this before, but notwithstanding the brilliant job they did saving as many people as thay managed to, the Captain and F/O of UA232 kept forcing their yokes forward and left even when it was having no actual effect on the flight surfaces. I suspect the answer is somewhere inbetween.

Just to point out a few indisputable facts:

Northwest Airlines Flight 6231 (B727) - PNF had yoke in his lap during stall, did nothing.
Birgenair Flight 301 (757) - PNF had yoke in his lap during stall, did nothing.
Air Florida Flight 90 (737) - PNF had yoke in his lap during stall, did nothing.

rudderrudderrat

6th May 2012, 15:51

Hi DozyWannabe,
I know you and others perceive the feedback loop as essential, but I'm not sure it is as essential as you believe it is when an airliner's flight surfaces are fully-hydraulic.
It doesn't matter that the flight surfaces are powered, it's more about being kept in the loop. e.g.
I can see the total fuel on board constantly, but the individual fuel tank gauges out of view, (they are on a systems page) so I get a warning when one tank is low, or an imbalance is building.

With the flight controls, I don't get any warning that I'm approaching maximum deflection with aileron or elevator, (or that the stab trim has run beyond it's normal range automatically). If I don't get that feed back through the side stick - then it would be nice to receive a warning somehow.

If AF 447 had some such warning, then I bet the Capt. would have been better able to diagnose their problem.

DozyWannabe

6th May 2012, 16:16

With the flight controls, I don't get any warning that I'm approaching maximum deflection with aileron or elevator, (or that the stab trim has run beyond it's normal range automatically). If I don't get that feed back through the side stick - then it would be nice to receive a warning somehow.

Understood. All that is fairly easily implemented without having to mess with the fundamental systems design and without having to add much complexity in software terms.

Of course in Alternate and Direct Laws, you know that full lateral stick deflection = full aileron deflection. In stall conditions, ailerons are more-or-less useless. What puzzles me is that the Captain tells them to use the "rudder bar" towards the end, but neither explains why nor does he explicitly state he suspects a stall - this leaves a lot of open questions. All that aside, I still don't understand how he could have seen an aircraft out of positive control with a rapidly unwinding altimeter - information that was clearly available to him - and not said "We're stalled". You shouldn't need to confirm yoke or sidestick position to be able to work that out if you understand aircraft.

Over the last few pages, those that consider yokes and feedback to be a panacea regardless of the circumstances are trying to hammer the known facts about this accident to fit a position they've already taken for reasons of their own, and yet they ignore incidents where an aircraft has stalled, the yoke has been back and the PNF did nothing, or (as in the case of the LH A320) they take the assumption that in a pressure situation a PF will automatically relinquish the controls as soon as a superior PNF touches them as hard fact, when there are plenty of incidents where that has not been the case.

Ian W

6th May 2012, 16:45

Over the last few pages, those that consider yokes and feedback to be a panacea regardless of the circumstances are trying to hammer the known facts about this accident to fit a position they've already taken for reasons of their own, and yet they ignore incidents where an aircraft has stalled, the yoke has been back and the PNF did nothing, or (as in the case of the LH A320) they take the assumption that in a pressure situation a PF will automatically relinquish the controls as soon as a superior PNF touches them as hard fact, when there are plenty of incidents where that has not been the case.

Logically your argument also supports removing all aural warnings as there are numerous examples of flight crew disregarding them.

Where your argument is weak is that it misses all the potential incidents that became non-incidents because of the extra information provided.

A33Zab

6th May 2012, 16:55

EgyptAir 990 (http://www.ntsb.gov/doclib/reports/2002/AAB0201.pdf) is indeed I did refer to.

I know it was initiated by FO but still the captain was unable to recover the situation.

Maybe summation (Airbii) isn't too bad at all.

All suggestions to improve safety/recovery should be considered.
but since this is a one time occurance NOT all the suggestions needs to be implemented, first of all they need to be effective.

The A330 is late 80 technology, CRT displays at that time were limited in performance and in symbology displayed at the same time.
Large LCDs in A380(and will A350) / 787 are capable to display a lot more information at the same time e.g. flight controls position.

For the AF447 the F/CTL SD page was automatically called and in view when F/CTL RUD TRV LIM FAULT ECAM was triggered.
In the BEA reports they do not mention any CLEAR action or SD page switching. (if recorded), the F/CTL page could still have been in view all the time.

CONF iture

6th May 2012, 16:55

The uncertainty is the issue but on balance the postion of the yoke will not make any difference to an appraisal of a situation. A337ab summed the situation up perfectly. A yoke will not help in this kind of environment.
The Lord has spoken.

A33Zab is more reserved that you are :
Maybe IF SS feedback/interconnection was available it would not have happened.

A330s have SS, and I doubt very much that Airbus will be looking at adopting "old" technology. More likely they make the pertinent changes to satisfy BEA recommendations
I certainly don’t see as necessary to go back to the "old" technology.
What is more sensible and necessary, is to openly discuss what the sidestick Airbus concept has suppressed. It is the role of Airbus, it is the responsibility of the BEA. But Old Carthusian can sleep well, never the BEA will approach the subject, far too sensitive, and if ever they do at my great surprise, it will be to better discard it as a contributory factor.

... Report in June ?

DozyWannabe

6th May 2012, 17:05

Logically your argument also supports removing all aural warnings as there are numerous examples of flight crew disregarding them.

Classic straw man argument - no it doesn't, because not only are those warnings necessary, but also there are plenty of incidents where they *have* worked. I'm sure there have been plenty of incidents where the override system provided by the sidestick design has worked to resolve a situation as well.

There is an argument for limiting the number of warnings at any given time - because of the Aeroperu and Birgenair cases, where the numerous and conflicting visual, aural and yes - tactile (stick shaker) warnings only served to confuse the flight crew.

I know that there's a lot of belief in some circles that the Airbus design was a deliberate attempt to design the pilot out of the loop and eventually out of the flight deck - this simply isn't true and never was. All the information you get from a traditional flight deck is there in some form or another, and if not, alternatives are provided. You may need to access that information in a different manner, but it is there, should you choose to use it.

No-one has even attempted to answer the question as to how the captain failed to deduce a stall situation despite the information right in front of him - asserting instead that if only the A330 had yokes he would have been able to. There's no evidence to back up that assertion, only supposition that it "might" have helped. The evidence available from similar incidents suggests that it's just as likely that it "might" not.

In a situation which is outside the realms of SOP and checklists, a good, professional aviator should use the information and tools available to resolve things. All the evidence suggests that enough information was there to do so, and the tools to do so provided. The yoke argument is a red herring here.

rudderrudderrat

6th May 2012, 17:06

Hi DozyWannabe,
or (as in the case of the LH A320) they take the assumption that in a pressure situation a PF will automatically relinquish the controls as soon as a superior PNF touches them as hard fact

I'm glad you raised this one because it perfectly shows what happens when the crew don't realise how much aileron is being applied to satisfy their roll request. They both applied full roll side stick, but because it was in ground Law - they only got half aileron (above 70 kts)!!! ???

From page 46 of
http://www.bfu-web.de/cln_030/nn_226462/EN/Publications/Investigation_20Report/2008/Report__08__5X003__A320__Hamburg-Crosswindlanding,templateId=raw,property=publicationFile.pdf/Report_08_5X003_A320_Hamburg-Crosswindlanding.pdf

"The aircraft touched down shortly after the 1,000 ft marker in the touchdown zone, about 2 m left of the runway centreline lights with the left wing 4° down and the fuselage pointed 2° to the right of runwayallignment, whereupon the rudder pedals were returned to the neutral position.

The aircraft yawed towards the left, thereby increasing the lift from the right wing and decreasing that from the left wing. In spite of the co-pilot's right sidestick correction, this resulted in unintended contact between the downwind main landing gear and the runway. The objective had been to land with wings level. This was confirmed by the correct application of right sidestick prior to touchdown, which was intuitively supported by the Captain's sidestick (dual input).

After touchdown the aircraft yawed a further 5° to the left. The left main landing gear lost contact with the runway. At no time did the right main landing gear make contact with the runway. Lift dumpers (partial spoiler extension) remained inactive, because the necessary prerequisites were absent.

During the next few seconds the aircraft rolled to a 23° left wing down attitude in spite of the full right deflection of both sidesticks and application of right rudder. The switch to Ground Law limited the effect of roll control corrections. The left main landing gear again made contact with the runway. At about the same instant, the left wingtip made contact with the runway."

Page 48 "The investigation showed that the pilots could not have been aware of the crosswind flight control characteristics in close proximity to the ground and which were dependent upon the aircraft design. It is impossible to clarify whether the pilots would have taken a decision for a go-around procedure earlier had there been a risk evaluation that included aircraft system behaviour, then unknown to the crew, in this wind situation with the possible effects of gusts. The BFU is of the opinion, that the respective knowledge would probably have influenced the decision."

DozyWannabe

6th May 2012, 17:13

I'm glad you raised this one because it perfectly shows what happens when the crew don't realise how much aileron is being applied to satisfy their roll request. They both applied full roll side stick, but because it was in ground Law - they only got half aileron (above 70 kts)!!! ???

I know. It doesn't alter the fact that there shouldn't have been a DUAL INPUT situation in the first place. Even if they didn't go around as soon as stability was lost (which was the best case scenario), the captain mishandled the procedure for taking control.

It was a high-pressure situation, so it's understandable that instinct overrode training. However, despite assertions to the contrary, there's no guarantee that the outcome would have been any better with yoked controls - in fact if it had triggered a startle response in the F/O it may even have been worse.

@CONF - you do realise that the accusation of arrogance you're levelling at A33Zab for saying what he's saying can also be levelled at you for insisting that yokes solve everything and are an objectively superior control method, don't you?

PEI_3721

6th May 2012, 17:30

Lyman, re #407 "The Airbus side stick system lacks the "position of the control surface feed back loop" to the pilot. We have no easy method to see how much control surface deflection is required to satisfy our side stick input. It is very useful for an experienced crew to know."

The MD-80 and BAe146 with conventional yokes lack positional feedback …
The issue is the lack force feedback, either actual or artificial from control input and trim position. This stick-trim force provides a measure of deviation from trim speed.

In a conventional aircraft the residual force has to be zeroed manually; in some FBW aircraft it is removed with automatic trim follow up (Airbus). In such systems, either side-stick or conventional column, it is normal to provide a centring force indicating an error from the null input.
FBW systems are not ‘wrong’ etc, just different, and may require an alternative means of detecting speed error and/or (mis)trim position. This is normally via instrument displays - the ASI; note industry concerns over poor instrument flying skills and dependency on autothrust, there is less requirement to ‘look after’ speed.
With the lack of an airspeed display, a FBW aircraft has no backup of sensed trimmed position as with a conventional aircraft (no stick-force for trim speed error), thus it is important to look at the physical trim indication and be aware of the need to null any stick input when the desired flight path is achieved.

As an example; - the need for a small pitch change when flying without an airspeed display.
In a conventional aircraft the pilot moves the stick and in time will have a force proportional to the trim speed error – large error, high force, this is a cue to trim and/or relax the input.
In a FBW aircraft there is no need to maintain the input once the flight path/attitude has been achieved, the side stick should be centred (a reversed sense of movement) and, providing the auto trim has followed up, the aircraft will maintain the flight path/attitude (may depend on control law) – and the resultant speed will depend on thrust, configuration, etc, etc (no autothrust).

As a hypothesis, would a novice pilot trained on conventional controls (little hands-on experience in FBW aircraft) ‘revert to type’ – using conventional control input strategy when faced with a challenging situation in a FBW aircraft, i.e maintain stick input/position?

rudderrudderrat

6th May 2012, 17:33

Hi DozyWannabe,
there's no guarantee that the outcome would have been any better with yoked controls
Well I'm afraid we'll have to disagree on that one.

On the TriStar, operating to Bermuda with strong crosswinds and only Island Holding fuel, we would sometimes have to land in limiting crosswinds. If we attempted to align fully with the runway using rudder, we could feel when we were about to run out of aileron control (by the position of the yoke), so we would have to relax the rudder slightly and accept touching down with more drift.
(& full aileron control was available on the ground, even above 70 kts)

None of that feed back is available with Airbus FBW.

there shouldn't have been a DUAL INPUT situation in the first place.The fact that they got reduced aileron control on landing was not due to DUAL INPUT - it's simply a function of "on ground" mode.

Organfreak

6th May 2012, 18:32

DW:
you do realise that the accusation of arrogance you're levelling at A33Zab for saying what he's saying can also be levelled at you for insisting that yokes solve everything and are an objectively superior control method, don't you?

Some of us are heartily sick of this failure of logic of yours. OK, I am! :O

Few, if any, have said anything about it being "superior" or would "solve everything." And you talk about straw men! I, and others, have said until we are blue in the face, (like this): :confused: that it MIGHT have helped. WE can't prove that it would have, and YOU can't prove that it wouldn't. This is simple logic. Very experienced pilots here have opined that it might have helped. You are fighting a battle that you just can't win; give it up, man! This issue is the MAIN thing causing the hamster wheel to go around endlessly. No one will ever know if it would have helped.

As an educated SLF, When I am riding in the back minding my own business, I expect that EVERY POSSIBLE SAFETY MEASURE is in place (if it were not prohibitively expen$ive). Not rocket science. You sound like one of those accursed bean counters, or else there's some sort of bias that we don't know about. /rant

CONF iture

6th May 2012, 18:35

@CONF - you do realise that the accusation of arrogance you're levelling at A33Zab for saying what he's saying can also be levelled at you for insisting that yokes solve everything and are an objectively superior control method, don't you?
Where are you going with that one Dozy ... ?

Accusation of arrogance towards A33Zab ??? Please explain.
Where do I insist that yokes solve everything ? Please quote.

Sidestick Airbus concept suppress information of great value for a crew : It is a fact. You can quote me on that one.

DozyWannabe

6th May 2012, 18:53

Sidestick Airbus concept suppress information of great value for a crew.

You say "suppress", I say "supplies differently where that information is indeed necessary". The flipside is that the sidestick system comes with safety features and benefits that are not available with interconnected yokes - this is also a fact.

@Organfreak - as many very experienced pilots have opined that it might not make a difference as have that it might. This isn't a "failure of logic" on my part either, I know full well the posting histories of some of those I'm talking to - some of them have outright accused Airbus of being in cahoots with airline beancounters to sideline pilots. People asking "why won't they interconnect the sidesticks?" not only seem wedded to the idea that interconnection is a positive in *every* case (it isn't) - but, as importantly, don't seem to have grasped that interconnecting the sidesticks would defeat several safety features inherent in the design.

Regarding "every possible safety measure" being in place - interconnected yokes are *not* a safety measure by any objective standard. I know you're a Boeing man, but give a little ground here, eh?

OK465

6th May 2012, 18:58

bye maybe someone knows what you mean

B44:

It wouldn't let me link to page 72 (Spoilers), but once you get it open go right to page 72. :)

B 757 General Familiarisation in Maintenance (http://www.scribd.com/doc/51695947/B-757-General-Familiarisation-in-Maintenance)

(Sorry to interrupt CONF :))

Organfreak

6th May 2012, 19:03

DW:
I know you're a Boeing man

No, you don't.

DozyWannabe

6th May 2012, 19:27

No, you don't.

I'd swear you'd said something along those lines previously - I may be wrong, and happy to be corrected. I'm sorry if you're offended by anything I've said - but I don't like situations where all the cards aren't on the table.

You asked if I have a bias? Yes I do - I am biased towards lack of bias, objective criticism and dispassionate observation, nothing more. If a very experienced pilot, or anyone else for that matter, says they feel uncomfortable about the lack of tactile feedback inherent in the system - that's their call and I won't say a peep. If they say on the other hand that tactile feedback is inherently safer with no concrete evidence, then I'm likely to refute the statement. If they are unaware that the design of the system has safety benefits that the traditional yoke does not, I'm well within my rights to point that out.

The fact that Airbus and Boeing share around 50% of the market each and have done for over a decade with no statistically significant safety discrepancies between them proves conclusively that whatever the benefits and drawbacks are to their control designs, both are valid and safe ways of doing it.

Kneejerk calls to change the sidestick system's design based on one possible factor in a single incident are wrong-headed and ludicrous, and they only ever seem to go one way. No-one went round suggesting that Boeing retrofit the 757 with sidesticks because the Birgenair PNF didn't do anything when the aircraft was stalled - why should it be any different with the A330 and yokes because of AF447?

Lyman

6th May 2012, 21:15

My sincere apologies to rudderrudderat for not attributing my quote in #407 to him, in 406.
PEI_3721 :

"With the lack of an airspeed display, a FBW aircraft has no backup of sensed trimmed position as with a conventional aircraft (no stick-force for trim speed error), thus it is important to look at the physical trim indication and be aware of the need to null any stick input when the desired flight path is achieved."

I was not focused on Stick force, per se, but on the lack of awareness PF had of his Pitch... To lower the NOSE, he has to overcome the springs, even though the a/c cooperates fully, (or would) in his command for descent(s)? IOW, and this sounds disrespectful of him, but is he "mistaking neutral for level?"

One assumes he was better treated in ROLL, as he seems to have sussed DIRECT LAW re: ROLL rather quickly. How is it his inputs were fundamentally on in correction angle, (only in rate did they alarm, and that soon settled out).

So, unfamiliar with "miss twitchy", he does a splendid job (DW, PJ2). (I disagree, ROLL remained a serious issue). Yet in PITCH, g controlled, he screws up quickly and chronically..... Do his actions, that result in "Level" (though climbing) emanate from sussing a "new normal" each time he lets up on Back Stick?

What are the two looking at, if they had attitude, how in GOD's name do either one not see the Nose well into blue? And what do you make of the conversation re: trend? I cannot figure what they refer to as trend, does "going up?" mean positive ROC? Or does it mean "inputting a command for climb?"

I think the allusion to ab initio (or medial) reversion is sound. He is a glider pilot, and cannot fly 330 as a Schweizer....

CONF iture

6th May 2012, 23:42

Kneejerk calls to change the sidestick system's design based on one possible factor in a single incident are wrong-headed and ludicrous, and they only ever seem to go one way.
Maybe stop creating stories of your own, then you won’t need to fight them.

Accusation of arrogance towards A33Zab ??? Please explain.
Where do I insist that yokes solve everything ? Please quote.
DW, any chance you assume those statements at least, or is it free speech again with no backbone ?

jcjeant

7th May 2012, 00:20

After analyzing hundreds of messages including the elements trying to show that the pilots are not fully responsible for the accident .. I conclude ( the sad reality) that none of the explanations fail to hold harmless the lack of professionalism of the pilots
Since setting up deep stall to the imposibility to recover from it .. is comparable to performances of poor beginners despite their experience (their licenses of liner pilot and flight hours on paper)
I can compare them (their piloting skill) to the September 11 terrorists .. but them .. despite their poor piloting skill and inexperience on type .. they have completed their mission that was to kill people
The mission of the Air France pilots was to save people .. and they have not fulfilled their mission
Maybe crude and rude .. maybe some think like this but don't speak of it .. but after all ... why not ?

Lyman

7th May 2012, 01:09

My friend, I hope you reconsider. The two things are not even alike, at all. We already have many helps to explain what happened, and although it seems the pilots were somewhat at fault, you must consider what you say. There was no evil on board or on the ground in connection with the tragic loss of 447. I am angry with some involved with crash of AF, but they are humans, too, and likely suffer with the rest of us....

Take a breath mon ami.

PJ2

7th May 2012, 02:02

jcjeant: Wow.

Lyman;
How and in what way does a roll to a bank angle of about 8deg either way "remain a serious issue"? I'm referring of course to "Phase 1", which is from the initial UAS event until the onset of stall-warning or the apogee.

The evidence that the PF got the roll under control quite quickly is in the data - it is a series of diminishing oscillations - a stabilizing (reducing) pattern of divergences, between left and right.

Now, as the AoA increases and lateral stability decreases, roll commands increase again and along with everything else roll becomes increasingly unstable, but all this occurs after the stall warning and just a bit later, the stall at apogee.

Even if there is some incidental pitch up command, both pitch and roll are eminently controllable with small movements and a normal response to an incidental pitch-up which is not desired, (for sure, not at FL350).

Ideally, one flies the airplane, which here means that the pitch is lowered and stick movements subside, (stick held fast), while the mass of the airplane settles down in the thinner air, then one returns to cruise altitude, etc.

Lyman

7th May 2012, 02:52

My take is that as well as PF did in his containment of his initial overcontrol in ROLL, he was unable to sense a neutral, in PITCH attitude. I would have expected that due to DIRECT LAW in ROLL, it should have been the reverse.

Simply put, PF was chronically either a) seeking to slow, or b ) seeking to avoid a descent. What other than those two would explain a chronic UP input? You point to his remedy of ROLL in "Phase 1". Later, with excursions in ROLL of over 40 degrees either side, he kept the bird from turning over. Again, a "mastery" of lateral. But an acute misunderstanding of PITCH.

Do you expect any surprises in BEA "Final"? I think most everything was anticipated at great length here. Do you think they will address UAS in full, for instance, discussing loss of Radome? How in depth will they go in analyzing the vagaries of the newest nemesis " Microcrystalline Water Ice"?

Will they rehash the badness of reselecting AutoPilot whilst in NCD?

A month to go, then with renewed vigor.....

all the best,

PJ2

7th May 2012, 04:30

Lyman;

"My take is that as well as PF did in his containment of his initial
overcontrol in ROLL, he was unable to sense a neutral, in PITCH attitude. I
would have expected that due to DIRECT LAW in ROLL, it should have been the reverse."
Some edu-guesses - they could be way off base, but an attempt...

The airplane is more sensitive in Alt Law in roll but once one gets used to it, it is controllable using tiny inputs. Being unable to sense a neutral point would be difficult because it is strong enough in the SS to feel it, but if distracted or under pressure, perhaps not as easily. The way to find the null in either yoke or SS is to let go of the controls for a moment - in most cases nothing immediate would occur and one starts from the null point. The airplane is less sensitive in pitch, but in pitch one is changing the trajectory of the entire mass, and in thin air, whereas in roll, one is (in the immediate sense), not asking anything more of the airframe than a change in bank - other than the engines, fuel and wing-structure and some resistance from the vertical and horizontal stabilizers, one isn't immediately changing flight-path which requires much more work. Just edu-guessing here...remember, I'm not an engineer!

"Simply put, PF was chronically either a) seeking to slow, or b ) seeking to
avoid a descent. What other than those two would explain a chronic UP input? You
point to his remedy of ROLL in "Phase 1". Later, with excursions in ROLL of over
40 degrees either side, he kept the bird from turning over. Again, a "mastery"
of lateral. But an acute misunderstanding of PITCH."

Possibly - this has been discussed at length in thread 2 or 3. The baro alt decreases about 300ft initially then recovers quickly - it did this in the Air Caraibes event as well. Seems a characteristic of this event. Even if this was an over-reaction by an inexperienced-at-manual-flight-in-cruise pilot, (and there, most of us are the same!), it is easily controlled by gently pitching back down and settling the mass of the airplane. But no. The pitch continued to increase. There is lots of blue on the PFD, and one should be getting very (very!) twitchy where one's behind meets the seat if you get my drift - high pitch angles at cruise are an instant "full-alert" & "get it down", now, kinds of occurences.

On pitch, I suspect right after the apogee and by the time the bank angles were reaching 40deg, (only at one point in the descent), a differently-developing psychological state began overtaking the crew, esp the PF. It is well known that high stress exhausts intellectual resourcefullness and perceptions - this was mentioned in the Alaska Air 261 MD80 jackscrew accident off LAX. I think this would be addressed in the HF section of the Report. A rational assessment of pitch was perhaps less possible as a visceral, self-preservation response developed from a state of increasing loss of SA - the solidly-held up elevator occurs twice in the descent and for a protracted period of time. The same phenomenon was recorded in the Airborne Express DC8-63 (http://www.ntsb.gov/doclib/reports/1997/aar9705.pdf) stall accident in 1996.

"Do you expect any surprises in BEA "Final"? I think most everything was
anticipated at great length here. Do you think they will address UAS in full,
for instance, discussing loss of Radome? How in depth will they go in analyzing
the vagaries of the newest nemesis " Microcrystalline Water Ice"? "

I think the surprises will probably be in the emphasis the BEA places on various aspects of the accident and not in what may or may not have been missed. There will be absences in the report that will be puzzling to some I suspect but that comes from one's particular POV and not necessarily from the importance of one or another aspect of the accident. The three IR's are thorough, particularly the third and address HF/Ops matters such as SOPs, CRM and so on and I think that will be the most examined. It is reasonable to consider that the stall warning, AoA indicator (raised in the Airborne Express accident), and THS items will be discussed but it is hard to say how, primarily because the airplane performed as designed and certified. It will be interesting to see if the sidestick issue is discussed. I think it will be minor if at all, primarily because it remains a demonstrably successful design and there are some counter-examples where the yoke design hasn't prevented the stall or crash, and because the expectation that design engineers cannot be expected to design against all possible circumstances. Something like that anyway...it's all a guess.

I hope the UAS issue will be addressed from a number of viewpoints. As you know I think the drill and checklist are poorly-crafted, poorly-trained and to put it simply, confusing. There are a few documents which have surfaced over the past year or so that put meat on this memorized drill and read-do QRH checklist so perhaps with such supporting training it's okay as written. The FCTM emphasizes items that are not at all clear in the drill. I think the PF was executing what he knew from a previous sim which was the memorized drill just after takeoff which is entirely the wrong thing to do at cruise altitude but this isn't clear as evidenced in the discussion in thread 5 or 6. I've had a go at re-designing it and it seems to work but there are always considerations that at first aren't obvious and maybe the drill as-written is still the best. I think the pitch-up was intentional and it rapidly confused the PF and the PNF did not take action, did not challenge what was happening and did not stop it, which, to me and many others, would have been obvious once seeing a pitch attitude of 10 - 12 degrees at FL350 so I think there is a cultural thing (broadly HF) here that will show up in the report. This has already been mentioned with regard to two F/O's, cockpit gradient, Captain's briefing etc.

There was no loss of radome until impact so it won't be discussed.

I think the discussion of ice formation and loss of pitot function will be extensive, as will the pace and decision-making process regarding actions and replacement prior to the accident. I think it may be a summary of thinking and design changes already done. But also it deserves the same kind of treatment say, that the ice-formation in the Trent 900 received in the BA777 Report.

I think also there will be questions/comments for all parties regarding awareness, training and checking given that the industry had had thirty-odd UAS events in cruise yet it didn't appear to be making them a part of recurrent training. I never once saw any such abnormal in the sim yet they were out there, post-1996. Other already-required scenarios may have crowded out the time needed for this but it was a demonstrable threat which, to me, was not handled in the way we ourselves are trained when we are doing threat-and-error management in the cockpit. I can't ever recall it even being discussed.

"Will they rehash the badness of reselecting AutoPilot whilst in NCD?"

I can't recall - did the crew do that and was it potentially a factor? Regardless, I suspect it won't be discussed except in passing. The Bulletin was issued and is part of SOPs.

"A month to go, then with renewed vigor....."

It's an extremely challenging report to write - I think it will be longer than June but again, a guess. I suspect the translation will be even longer still.

Machinbird

7th May 2012, 04:41

I've been dinking around with this and here is what I've come up with on the right turn after the stall (after all, why not a left turn?)

First, there was no "uncovered setting of the rudder trim that became exposed by Alt2 as I had earlier suggested there might be.
The autopilot has authority to trim the rudder in the same way that the pilots can and did so a number of times up to the AP disconnect. It was with the last A/P rudder trim setting that AF447 did its descent.http://home.comcast.net/%7Eshademaker/AF447Yawtrim1.jpg
Before the AP disconnect, there are some small trim adjustments on the order of 0.2 degrees. ranging from -0.25 to -0.5 degrees. After the AP disconnect, there are some small blips in the trace, but the indications remains as before. The position moved to -0.4 degrees seconds before the AP disconnect and that is where it stayed. -0.4 degrees has the effect of being a slight right rudder input. The reasons for the blips in the trace are unknown, and are most likely caused by noise on the circuit, or mechanical slop in the indicating system.

The effect of slight rudder trim would be minimal until the AOA began to run up, at which point, it would cause a preference to drop the right wing in a stall. The turns that are observed after the stall would then result from this preference plus pilot inputs on the rudder.

This probably repeats the evaluations of others, but now is my own.:O

When I pulled the clean F-4 into a stall and held it there, the aircraft would drop off on a wing. If I then applied opposite rudder gradually increasing, it would then flop over on the other side without being able to stabilize it even momentarily in a wings level mode. If I continued doing this ruder exercise, the aircraft would reverse itself yet again ever more violently. This is the experience I use to explain the AF447 post stall behavior although the A330 has a very docile stall by comparison.

Machinbird

7th May 2012, 05:00

Before there was loss of situational awareness of nose attitude, there was loss of situational awareness of altitude.

It is unimaginable to me that anyone who thinks they are a competent IFR capable pilot could completely lose the bubble on this, yet both PF and PNF allowed the altitude to get completely away from them and made almost no effort to put the aircraft on altitude. With the gain in potential energy came a loss of kinetic energy and this finally led to a stall.

The only thing that makes sense is that the roll problems were so concerning, that both pilots concentrated on that to the exclusion of their altitude scans. :hmm:

Old Carthusian

7th May 2012, 10:37

CONF iture
Human factors are the vital things to consider here - how the crew reacted to the situation. The sidestick/yoke thing is just window dressing with no real relevance to the accident. There were so many other inputs the crew could have obtained without reference to a hypothetical yoke. What makes you think that given their inability to access the information they had available that a yoke would have made any difference? What you posit is a wish state - you wish that a yoke would have provided the solution because your prejudices are inclined that way. I have no problem with you preferring the yoke but once you depart from the objective standpoint you end up in the area of speculation. We do know the following - the sidestick works and works safely. There are thousands of examples flying around at the moment. The yoke also works and works safely. Like the sidestick it does not guarantee that if a PF does something strange the PNF will react. It is not about being able to see and we have examples of where the PNF could see the yoke and did not act. I would also suggest you consider this point. In a high stress situation your interpretation of the actuallity may be considerably different to what things are. That is why the scan is so important - your instruments will tell you what is actually going on not what you believe the position of the stick is. We have a flight crew non performance here and given the evidence we have this crew would have not been able to deal with the situation no matter what their input device was. That is the sad reality.

Owain Glyndwr

7th May 2012, 10:57

This will be too long for a single post, but I think some of the comments will resonate with some contributors ...

Part A
On 20-21 March the Royal Aeronautical Society held its first 'The Aircraft Commander in the 21st Century' conference. Organised by the RAeS Flight Operations Group, the conference sought to explore the changing role of the aircraft commander, particularly as civil airliners get ever more automated and complex. This issue has recently been thrown into sharp focus, as incidents such as Qantas QF32 and Air France AF447 have demonstrated differing responses from pilots to ever more complex aircraft.

In particular, the industry now is reassessing the training given to pilots. A major theme that emerged from the conference was that, in the past 20 years, pilots have been taught to 'Follow the ECAM [(Electronic Centralised Aircraft Monitor]' - the computerised glass display that in Airbus aircraft (and Boeing aircraft as the EICAS Engine Indicating and Crew Alerting System) which shows critical engine and systems information. While this ECAM display makes life easy in many respects, (but which), if followed blindly, can lead to disaster. Previous training, said one speaker, relied on following the ECAM procedure step-by-step and pilots 'never considered not doing the procedure'.

This issue of displays showing spurious information was highlighted graphically by the keynote speaker at the conference Captain David Evans who, as a Qantas A380 training and check captain, was one of the five flight deck pilots who successfully resolved the QF32 incident in November 2010 after the 02 Trent engine suffered an uncontained failure. With the ECAM 'information overload' deluging the crew with a barrage of error messages the experienced captains had to sort through and examine what these meant for the aircraft. In particular, the ECAM recommended that the crew shift the fuel balance from one wing to another, as an error message said 'wings not balanced' as the imbalance limit had been exceeded. However, the reason why the aircraft was becoming unbalanced was that there was a serious fuel leak caused by the exploding engine - a situation that was obvious to anyone looking out of the window and seeing the damaged left hand wing leaking fuel.

Yet, had the crew followed procedure to the letter instead of 'using the force' and disregarding the computer, they would have ended up pumping fuel into a leaking fuel tank with consequences. At the very least this would have dramatically shortened the available time for the crew to think through and solve the problem.

Reliance and dependence that the computer always knows best can be dangerous. As Captain Evans notes: "What needs to be brought back into the skies is a 'healthy scepticism' about technology". This view was echoed in a later presentation by Captain Scott Martin, an experimental test pilot at Gulfstream, who said the correct approach was to treat the cockpit automation
'like a third pilot' but to be prepared to question it if it was not making sense. In the final analysis, says Evans - 'airmanship' or 'does this seem sensible?' should trump any automated ECAM/EICAS messages.

Yet this natural suspicion of technology runs counter to the future generations of pilots who will be drawn from today's 'Generation Y and Z' now at college or school. As Evans and others point out, these future captains born in the 1980s and 90s, while being able to grasp new technology and systems far quicker than their predecessors as well as absorb new information, will also, growing up with computers, iPads and smart phones, instinctively trust technology more.

The problem is not only one of younger pilots relying on technology too much but also of older pilots who may be losing touch with basic flying skills after years of relying on the autopilot. Though aircraft accidents remain rare - a noteworthy statistic from the conference showed that while the most common incident was a runway incursion/penetration - the most lethal in terms of lives lost is now loss of control in flight (LOC-I).

Lessons from QF32 are already making their way into Qantas' training. At the conference Captain Evans explained how Qantas has started to introduce simulator scenarios based on real (but rare) scenarios to expose pilots to difficult command decisions.
One example chosen for a recent simulator LOFT (Line oriented flight training) exercise was the scenario of flying an A380 through a volcano ash cloud, which could simultaneously set off fire alarms on the flightdeck and elsewhere (thanks to smoke detectors) as well as flame out the engines.
In the simulator exercise, pitot tubes would also be blocked by ash.
So what happened? With smoke warnings, engines flamed out, the airspeed went blank and the aircraft went into direct law with no autopilot. In particular, Evans noted, the ECAM logic prioritised the multiple ( spurious) fire warnings over the engine flame out warning. However for the pilots, understanding that the ash had caused the smoke detectors to trip, the priority should be to restart the engines.
This simulator exercise clearly demonstrates to pilots how a highly automated aircraft could revert to a challenging manual flying task for the pilots - whilst simultaneously presenting them with information overload in the form of ECAM messages.
However, doing this in the sim allows them to hone their command and decision making skills in a safe environment.

Owain Glyndwr

7th May 2012, 11:00

Here is Part B

Emirates Airlines is also adapting its approach to training in the light of recent events and is aiming at the highest standards, a point well made by Captain Martin Mahoney, SVP Flight Training at Emirates. To that end, the carrier has introduced a 'basic aerodynamics' course to refresh new entrants about the fundamentals of flight. Intriguingly, it has also reversed the trend for distance learning in favour of a return to 'chalk and blackboard' classroom learning.
Why? Captain Mahoney contends that not only do pilots learn better by being in the presence of other pilots (as well as reinforcing the pilot culture - an important factor in multicultural airline like Emirates) - but also in that the instructor can watch the students' eyes to see if the lessons have really understood. . In addition, Emirates is also boosting its pilots' skills with two manual handling simulator sessions every year for new commanders.

The airline has also introduced personality profiles for command upgrade candidates which are pilot's eyes only (management does not see them) and which provides potential captains with individual, practical feedback on their leadership style as well as strengths and weaknesses. However, Captain Mahoney had harsh words for ICAO's Level 4 English standards - arguing that they are "not worth the paper they are written on". In fact, he revealed that recent simulator tests of pilots from an unnamed defunct European charter carrier saw a 50% failure rate due to their English not being up to the standard needed by Emirates

Though the flightdeck is regarded as the gold standard for CRM (crew resource management), there maybe lessons from the medical sector, especially from surgeons, who have a similar high-skilled job with large responsibilities and operate in teams.
Indeed, Professor Rhona Flin, an industrial psychology expert at the University of Aberdeen observed that that in order to access and fully exploit the 'working memory' (analytical, which experts now believe can hold up to four 'chunks' at the same time), it may be a case of the 'slower the better'. She noted that one surgeon had once been given advice "Don't just do something, stand there", indicating that slowing down rather than rushing into action may contribute to better decision making in medical operations.
Though this may not be possible in some circumstances (Captain Sullenberger's Hudson ditching and the BA 777 Heathrow landing short of the runway needing fast reactions), taking a step back from the flashing displays and warnings may actually improve critical thinking. Was it perhaps due to the extra critical thinking time brought to the QF32 incident by five experienced captains that resolved the problem successfully?
Conversely, when thinking time is limited decision-making relies on long-term memory containing models of the world that we use, together with procedures and experience. These might be characterised by 'the gut feeling' or 'we've always done it this way'. This may work in some instances but, in more novel or unexpected situations, may make pilots (or surgeons) make the wrong choices or continue down an incorrect path - even when it is obvious in hindsight that the decision was the wrong one.

That aircraft (and crews) are now safer than ever is not in doubt and the statistics bear this out. However, the aviation industry is always striving for perfection. Furthermore, there is a growing unease that the previous ways of learning (and command) need adapting to new and future generations of automated aircraft. Ex-military pilots with 'nerves of steel', experience of flying at the edges of the envelope yet unwilling to talk to juniors have given way to systems managers and team players. However, these new pilots, fluent in the latest crew management skills, may also be lacking some basic 'stick and rudder' skills and be too willing to trust the computer.

The highly automated aircraft also provides fresh challenges. The issue is not the technology itself but the gulf between normal and non-normal (i.e. emergency) operations. In normal operations a highly automated airliner is easier to fly than previous generations of aircraft but, in a non-normal situation, it is comparatively harder.
It is this gulf between normal and non- normal which is the issue and is so difficult to train for because of the extreme rarity of non-normal emergencies. As one speaker pointed out, in the old days he had flown as a third pilot observing the crew routine and watching them deal with multiple engine failures as part of his apprenticeship to command. Today, a trainee captain riding a jump seat as an observer would be extremely unlikely to witness an in-flight emergency to 'learn' from the more experienced crews.
In short, some forward-thinking airlines are already adapting their approach to training and command issues in making sure that the aircraft commander of the future has the correct mix of technical and non-technical skills and, more importantly, knows when to ignore, question or override the computers. As Captain David Evans observes, the commander must: "work out
the solutions with the help of technology, not depend on technology for the solution".

RetiredF4

7th May 2012, 11:12

OC
your instruments will tell you what is actually going on not what you believe the position of the stick is.

absolutely correct, but.....

..........the instruments dont tell, why something is happening.

A climbing indication can be caused by an intentional stick input, by turbulence, by an updraft, or by a stick input seconds before. The aircraft can still be in a climb, the pitch can still be positive, the VS can still be positive, and the Stick is in neutral or even forward.

In the F4 we had no autothrottle, but a possibility of autoacceleration of the engine with certain malfunctions (aux air doors failed). The RPM increased to 100%, but we could see the unchanged throttle position and that therefore it was a malfunction and not an inadvertent advance of power, which caused the RPM to rise. Had our throttles in the front and backseat not been interconnected, a rise in RPM observed on the rpm gauge in both cockpits could have been a malfunction or a willing act of the other guy.

In case of AF447 it might have been helpful for the PNF and the captain to know, what kind of SS input the PF was doing in assisting the process of correlating the behaviour of the aircraft with the !!!wrong!!! inputs of the PF, thus aiding in failure assesment and leading to problem solving. Same might be true for the THS trim position as well as the Throttle position.

As long as the PF is doing what PNF would do himself, as long as he is acting in the expectation pattern, the instruments give all necessary information. But it gets tricky, when the instruments do not correlate with the expectation pattern and there is no other means to crosscheck why that would be the case, because the instruments only tell you what is happening.

Now you have to evaluate what caused the discrepancy from the expected, turbulence? flight control malfunction? updraft? indicator malfunction? unintended flightcontrol input? Deliberate flight control input?

OC
We have a flight crew non performance here and given the evidence we have this crew would have not been able to deal with the situation no matter what their input device was. That is the sad reality.

That might be true, unfortunately.

OC
I have no problem with you preferring the yoke but once you depart from the objective standpoint you end up in the area of speculation.

Imho the standpoints don´t differ that much from each other concerning objectivity and speculation. Nobody knows what would have happened, when............
We know however what had happened with AF447, and that one was not desireable as many other accidents with or without SS / Yoke.

So it is worth to think over all issues, might they be liked or not.

Old Carthusian

7th May 2012, 12:14

Indeed some interesting points - however, I would go as far as to suggest that one shouldn't be operating on an expectation pattern. My instructors always taught me that you don't expect anything but you accept what the instruments tell you. Once you start to expect you run the risk of deviating from how things are and getting into a mess. Of course this may be different in military aviation but this is what I learned. Knowing what is often a vital factor and could be said to have more importance than why. The aircraft is climbing too quickly therefore put the nose down. Understanding why it is climbing can come late I would think.
I would agree with you about speculation but here the evidence points to human factors and crew non performance in such a way that the input device was peripheral and would have remained so no matter what. It does make one wonder how these poor people ever got onto an aircraft flight deck. Given, for example, that there seems to be no attempt to diagnose the initial issue in accordance with SOPs how would the input device have made any difference? In my opinion the breakdown in everything related to flight management and procedure was so complete it would overwhelm any system. That is why a discussion of whether a yoke would have helped is futile.

Clandestino

7th May 2012, 12:44

At first sight, this would seem to be preferable to the BUSS in an UAS situation. What are the disadvantages?It's wrong! Who wrote that? I did?!? Oh well... What I wrote was very simplified, and most probably oversimplified, illustration of the way low speed cues work on modern EFIS aeroplanes, without the need to know what's the actual weight. It was not meant to be taken literally as be-all and end-all definition of system operation. I strongly suspect your further line of thought, about showing wrong stall warning speed when IAS gets unreliable is correct and covers the reason why low speed cue gets shut off when IAS data is lost. BUSS is basically the same thing you are proposing: replacing IAS with AoA information. If someone said that having AoA display is great because fighter jocks use it would have shown impressive misunderstanding of the way things work in aviation. Yes, combat pilots of last thirtysomething years usually do have a little gizmo making their life easier during approach and landing, it's either doughnut & chevrons type AoA indexer or AoA bracket on HUD. It is there to make their already complicated life easier by reducing the need to accurately calculate their approach speed for actual weight plus any effect from external stores. No, it is not 100% reliable as AoA vanes do get stuck or birdstricken then it's reversion to monsieur Pitot again. Of course, one has to be proficient in its use, which can only be achieved through practice. It is of utmost importance to know that yellow light means stick back, red stick forward, not the other way around.

In transport aviation, we are more concerned with field and cruise performance maximization than with the shooting down the intruders or bombing the bunkers while dodging the flak. We're not great buyers of AoA gauges as airspeed indicators let us do that part of our job more precisely. What we do when we lose IAS and there's no AoA gauge to save our flying butts? We (well, most of us, most of the time) revert to old fashioned discipline, taught already on the basic trainers, called "pitch and power". I had to demonstrate safe visual circuit in C-150, with ASI covered, just using pitch and power to get my PPL and I'm pretty sure it wasn't just me.

The Airbus side stick system lacks the "position of the control surface feed back loop" to the pilot. Uh-huh. I can only imagine the rage, fury, indignation of the "If it ain't Boeing, I ain't going" brigade when Boeing abandons simple stick-to-control flight control arrangement and replaces it with hydraulic monstrosity that requires air data driven artificial pitch feel to be effective. If the day comes, we'd better hide the fact from them manual control freaks, lest we risk the riots.

Cost should never trump safety.In ideal world. I like better this one, it's more realistic:

Safety begins as a perceived value of human lifeIt's wonderfully politically incorrect yet it perfectly explains regional safety statistics.

Nevertheless, suggestion that Airbus FBW raison d'etre is cost and that cheaper must be less safe is completely misinformed or an indicator of recklessly pushed agenda. Or both.

If I had to enter that flight deck at that time, the first obvious clue would have been that full back yoke at 350 ... now call me unprofessional.Is this really what you're trying to do? Eliciting certain reaction? Well, it's nothing personal, but IMHO airline pilot who enters the flight deck in night IMC and does not look for the clues on the instrument panel displays unprofessional behaviour, definition of which is not entirely arbitrary as not adhering to professional standards in aviation can be lethal.

Sidestick Airbus concept suppress information of great value for a crew : It is a fact.It is not a fact; it is an opinion. In natural and technical sciences, opinions do not become facts just because some anonymous posters or mediapersonnae repeat them ad nauseam.

Now find me someone who really is an expert on the aeroplane flight controls and who can coherently, reasonably and non-anonymously state what you have written.

What is more sensible and necessary, is to openly discuss what the sidestick Airbus concept has suppressed. It is the role of Airbus, it is the responsibility of the BEA. But Old Carthusian can sleep well, never the BEA will approach the subject, far too sensitive, and if ever they do at my great surprise, it will be to better discard it as a contributory factor.

... Report in June ?Completely unnecessary ad hominem directed at Old Carthusian.

Anyway, BEA or any other safety agency does not give a rat's stern about PPRuNe or any other anonymous pilots' forum. Those who are not on PPRuNe to "elicit certain reactions" and thus receive their pay through others' responses, but rather really seek an improvement in safety, should submit their concerns direct to BEA.

However, there are two problems: you can't submit your theory anonymously. Second is that theory that in multi-crew enviroment, the assisting pilot must always know what is the control position of the flying pilot runs afoul of the basic instrument flying model of closed loop feedback via instruments, so there's good chance BEA will simply bin the submission. Of course, some sensitive souls might see it as an evidence to conspiracy.

The evidence is yelling at you..... Nope. The evidence, so far, has been neatly and unemotionally put down in the three interim reports. Only ones yelling are those PPRuNers who are taking some evidence out of context and ignore lots of other to push their own unsubstantiated view on the matter. Seems that some are preparing to pour their indignation on BEA's findings when the final report is out. Certain Teutonic gentleman has already warned us of such an approach:

The worst readers are those who behave like plundering troops: they take away a few things they can use, dirty and confound the remainder, and revile the whole.

Anyway, there were 32 cases of at least two pitots blocked on 330/340 before AF447. Did we discuss them here on PPRuNE?

Organfreak

7th May 2012, 14:23

Clandestino said:
....suggestion that Airbus FBW raison d'etre is cost and that cheaper must be less safe is completely misinformed or an indicator of recklessly pushed agenda. Or both.

OK, I accept the contention that I am, er, "completely misinformed," but, pray tell us, what are the advantages to the AB sidestick system if cost (weight savings) are removed as a factor? That is the only justification I've ever seen for such a design. Sure, it must be great to have a work table to fold down, but, what else? If you want to attack my opinion, please supply some solid facts. (add "it's OK, I'm not mad at you" emoticon) :)

Now, as for Mr. Glyndwr's contribution....
Thank you! It's a relief, to me, to see these factors being considered so sensibly. I say this because no-one has seen fit to comment on what could have started a very interesting discussion on something besides side-sticks and incompetent pilots. :D

DW:
OK, OK, I DO live in Boeing's back yard (and I don't mean Chicago!), and have for 60 years, but they get no halos or blank checks (cheques?) from me!

HazelNuts39

7th May 2012, 15:09

Basically, low speed awareness tapes are just alpha information superimposed on speed tape. (...) It's interesting to watch it bounce in turbulent approach or climb in turns, just as Alpha max red strip does on A320.
It's wrong! Who wrote that? I did?!? Oh well... What I wrote was very simplified, and most probably oversimplified, illustration of the way low speed cues work on modern EFIS aeroplanes, without the need to know what's the actual weight. It was not meant to be taken literally as be-all and end-all definition of system operation. I strongly suspect your further line of thought, about showing wrong stall warning speed when IAS gets unreliable is correct and covers the reason why low speed cue gets shut off when IAS data is lost. BUSS is basically the same thing you are proposing: replacing IAS with AoA information. Could we look at this more objectively? I'm aware that the 'low speed awareness' markings are fundamentally different from Airbus' markings of 'characteristic speeds'. But when airspeed has 'gone south' and in Alternate Law, may be the 'low speed awareness' is better? While the speed tape is faulty (maybe it should be 'greyed'), the 'low speed awareness' tape is valid, correctly displaying the stall margin. It would have informed the pilots of the 'validity' of the first brief stall warnings, that they were transient and no reason for concern at that time, and would have informed them of the approaching stall warning and stall later on. Would it, by confirming the PNF's feeling that things were going 'the wrong way', have convinced him to step in with more determination?

It doesn't have the big drawbacks of the BUSS that you lose all three ADR's for the remainder of the flight, and that it is virtually useless above (IIRC) FL250.

jcjeant

7th May 2012, 15:12

Clandestino
Anyway, there were 32 cases of at least two pitots blocked on 330/340 before AF447. Did we discuss them here on PPRuNe? No .. neither the BEA or DGAC for those on AF aircraft that were involved in this type of incident
PPrune , BEA and DGAC begin to discuss after AF447 case

Lyman

7th May 2012, 15:44

@Clandestino

Quote:
Anyway, there were 32 cases of at least two pitots blocked on 330/340 before AF447. Did we discuss them here on PPRuNe?

And where were the wise ones? "no harm no foul" ? PPretty myopic, imho.

KBPsen

7th May 2012, 16:05

No .. neither the BEA or DGAC for those on AF aircraft that were involved in this type of incident
PPrune , BEA and DGAC begin to discuss after AF447 case

Another one who believes that things they do not know about does not exist. Those who do not know how much they do not know, usually believes they know much.

Add petty francophobia to the mix and much is explained.

Lyman

7th May 2012, 16:38

Re: Myopia. Mr. Magoo, et al.

To those who believe that the Aviation industry is proactively concerned with Safety issues to the exclusion of profit, convenience, (profit), scheduling (profit), and low maintenance (profit), a klarion: Not Always....

Then there's Hubris, and arrogance. On top of Tradition, Culture, and Politics.

No one who is informed will clamor for perfection, it is not in the cards. We rely on others to assess our level of risk, and for 99 per cent of the Public, ignorance is bliss.

When Pilots go activist, pay attention. After 447, and it became clear that UAS was lurking out there for the unwary (which was everyone, by definition), a labor action was called, and wot, ho, get out the spanner Clive, (Laurent, Kim, Robin, et al).

Push, Shove, Pull. Politics is alot like flying....and verse for vise.

Was anyone not astounded that Airbus had the clout and power to demand a memorandum from BEA prior to the Show? I was not, anyone?

How much clearer can the rules be? Pay the Fife and drum, call the tune.....

Frankly, the more passion due prior ignorance, the better. Safety is directly proportional to the clamor of the client....especially so when the responsibles are not paying attention.

addend... PJ2. I included the Radome involvement in UAS generically, and here's why....

If the Final report is narrow, and addresses a limited number of issues, so as to frustrate the need for further understanding v/v the way a plane flies, and falls, more's the pity. UAS should be completely embraced and understood, to squeeeze it into the vernacular. How many airline pilots are fluent in Radome loss? It is an opportunity to further understanding of the event and its genesis, in this case and/or others. The readership of this document will be large, and I promise you, if stones are left unturned there will be pushback... It is in the interests of all for the report to be voluminous....

just my opinion....

Organfreak

7th May 2012, 16:49

This is a red letter day, because, for once, I totally agree with Lyman.

Sincerely,
Mr. Magoo's Seeing-Eye Dog

P.S. Arf.

HazelNuts39

7th May 2012, 17:00

To those who believe that the Aviation industry is proactively concerned with Safety issues to the exclusion of profit, convenience, (profit), scheduling (profit), and low maintenance (profit), ...I don't believe that it is, nor that it should be.

Lyman

7th May 2012, 17:06

Heartily agree.

DozyWannabe

7th May 2012, 17:10

Was anyone not astounded that Airbus had the clout and power to demand a memorandum from BEA prior to the Show?

Nothing shady about that though. It's not like they asked the BEA to falsify anything, just make public the information that they already knew - i.e. that no evidence of technical malfunction had been found.

The use of language by some on here (e.g. "demand" and "suppress") is very telling. "Request" would have been more valid and correct in this case.

A33Zab

7th May 2012, 17:35

Was anyone not astounded that Airbus had the clout and power to demand a memorandum from BEA prior to the Show? I was not, anyone?

Neither was I,

If experts are convinced the apparatus didn't fail, there is nothing wrong with protecting your business.
Boeing will do exactly the same when appropriate to Boeing.

If a serious flaw was detected the world would have know about it months ago.
(Like the Thales probes)

RetiredF4

7th May 2012, 17:59

OC
Indeed some interesting points - however, I would go as far as to suggest that one shouldn't be operating on an expectation pattern.

Let me explain what is meant by expectation pattern.
On your instruments you are flying straight and level and unaccelerated. You want to climb and for that you pull the stick back some amount and you expect the corresponding action of your aircraft on the instruments or by other appropriate means. Reaching the desired altitude you put the stick forward and you expect the pitch to decrease, the climb to stop and you check that again on the instruments, do some necessary corrections until you are again in level unaccelerated flight. By the way, if you didn´t expect an speed decrease due to climb, you probably forgot to adjust power.

If you are doing this on Automatics, you turn the necessary switches or / and pusch the buttons and expect again the automatics doing same as above, you monitor the action and the outcome on your instruments.

When PF is flying, PNF expects the PF to do all the steps above either in Automode or manual until the desired outcome is achieved, and again PNF will monitor on the instruments the correct application and the outcome.

If PNF does not expect a climb from autopilot or from PF, because it was neither intended nor anounced, and the instruments indicate a climb, he will not know, wether it is an instrument malfunction, turbulence, an autopilot malfunction, an intended or unintended climb by the PF. But the knowledge what caused the climb might be necessary to apply the correct action.

Let´s use speed as a further example to make my point clear:
Again straight and level, unaccelerating flight. On the instruments the speed tape is indicating an unplanned decrease in speed. Again it could be due to UAS (do nothing), due to unintentional climb (stop climb, descent back down), thrust change, autothrust malfunction (use manual thrust, set correct setting). Sure you check the other intruments, which will tell you why the speed is decreasing. This one shows, that you can get the necessary information of "what and why" from the instruments, but that will not work as nicely with the control around the axis of the airframe (pitch, bank, yaw), because the instruments only will tell you what and not always why.

OC
My instructors always taught me that you don't expect anything but you accept what the instruments tell you. Once you start to expect you run the risk of deviating from how things are and getting into a mess.

If we can agree to replace "expecting" with "guessing", i´m 100% with you.

But to control the effectiveness of an input, you have to rely on an corresponding reaction pattern. Simplest one being taught in the first flying hour: Pull on yoke, houses get smaller; push yoke, houses get bigger; Yoke left, house left side; yoke right, houses right side; throttle forward (depending on aircraft) engine noise louder, throttle backward, engine more quiet.

OC
Our instructors didn´t have to emphasize the why after the what, because we had the yoke or stick in our hands and knew why we where off the desired parameters.

Ever trained unusual attitudes with closed eyes? Instructor mistrims the aircraft in pitch and yaw and hands you the aircraft over while hanging upside down? You see the situation on the instruments and make the appropriate flightcontrol inputs, but you stop fightig the aircraft during recoveryy the moment you recognize the wrong trim (the why), because now you know why it handles that bad and you know the correct solution.

OC
Of course this may be different in military aviation but this is what I learned.

No, it is not. Guessing kills you already in peacetime albeit in war.

OC
Knowing what is often a vital factor and could be said to have more importance than why.

That is absolutely correct, but it does not make the "knowing why" unnecessary. It is not an either / or. It is a sequential thing. You have to know "what is happening" and the best path for an appropriate correction is to "know why" it happend.

It makes life easier.

PJ2

7th May 2012, 18:22

Owain Glyndwr;
I don't think PJ2 will be upset if I say that in my conversations with him he confirmed that on at least one occasion he executed a recovery from 30 deg AoA using 10 deg ND pitch - it took about 15000 ft.
Not at all, as such was the case in most scenarios we did. The 20,000ft + scenario had a number of factors which delayed recovery including a NU SS held, and thrust in the CLB detent.

What I have learned in these discussions with Owain Glyndwr and HN39 are the aerodynamics behind recovery and that one need not necessarily be extraordinarily aggressive with the airplane to effect a recovery. Now, maintaining a 10deg ND pitch initially required full-forward SS. The FPA indicator moved upwards from about 30deg ND to < 10degND at a rate of about 1 to 2deg/sec, more rapidly as the 10deg's was approached.

These understandings are not normally conveyed or taught in initial or recurrent groundschool or simulator sessions.

Even for those who have a deeper-than-expected understanding of high-altitude, high-Mach Number, swept-wing aerodynamics, I think there is great value for airline pilots in the following, which is I believe a rare glimpse into aerodynamic thinking which is quite apart from our traditional understanding autoflight systems and SOPs...

From Owain Glyndwr's Post #175 (http://www.pprune.org/tech-log/482356-af-447-thread-no-8-a-9.html#post7155753)

Suppose we start with pitch +15, Gamma -25, AoA +40 and instantaneously pitch
down through 25 deg to -10. (this is a thought experiment so we can do
that):

AoA remains at +40 for the moment as you suggest, but that means gamma goes
to -50. EAS hasn't changed, neither have CL and Cd at constant AoA so drag and
lift are unchanged. However we now have a large additional gravity component so
the aircraft will accelerate in absolute terms, i.e.TAS will increase, again as
suggested in a later post.

But in addition the aircraft is now descending more rapidly into denser air
so there is a double effect on EAS, and the thrust is also increasing due to
altitude effects which also helps a bit although this is not anything like as
important as the gravity effect since the maximum thrust one might get at say
FL350 is only about 7%W whereas a 25 deg FPA shift is worth 42%W.

If EAS increases at constant AoA the aircraft will develop an upwards
acceleration normal to the flight path and thence an upward velocity component
which, with the increased airspeed will result in a reduction in FPA. You can
see this in HN39's traces. [It will also of course experience an increase in
drag which partially offsets the benefits, but I think this only partially
offsets them]

A reduction in FPA, WITH PITCH HELD CONSTANT, will
give a reduction in AoA.

Cd is very sensitive to AoA above the stall, so the drag reduces more than
the effect of increased EAS and the whole response is "speed unstable" as it
were, with an increasing acceleration and reduction in AoA as time goes on until
the AoA is reduced to below S/W limits.

PJ2

7th May 2012, 18:35

Lyman;

With reference to loss of radome, ...if stones are left unturned there will be pushback...
Loss of the radome in flight due to lightning strike or bird strike and the effects upon CAS etc is already covered in the QRH. The Report must deal with what is; the radome was not lost in flight, the QRH already covers radome damage. This is not a stone-unturned.

Lyman

7th May 2012, 18:48

It is also not concluded that Pitots were blocked by ICE (granulitic), or ICE, solid.
Or by ICE at all? I believe it is assumed.....

Lonewolf_50

7th May 2012, 19:19

PJ2:
This is not as complicated as "OODA" and Boyd. The appropriate and correct responses are already there in the SOPs etc and do not require sophisticated techniques to address and correct. If the instantaneous and then sustained pull-up had not occurred as in the other thirty-odd UAS events there would be nothing to discuss here.
Indeed. Detailed comments after seing to Dozy's remark, but FWIW I was using OODA in the context of instrument scan. IMO you can overlay the basics of the OODA loop to describe the use of an effective instrument scan.
In one of the earlier threads, I asked "what we he seeing?" While most estimates are "his instruments showed him about what the PNF was seeing" (most analysis leads to "the RH flight instrument cluster was not acting up") we'll never know due to how FDR takes its information.
Dozy:
The junior crew on this flight didn't need an encyclopaedic knowledge of the A330's systems to recover, all they needed to remember was the stuff they learned back when they were doing their PPL - namely recognising the symptoms of, and recovery from, a stall (which are more-or-less the same whether you're flying a microlight, a space shuttle or everything inbetween). Unfortunately airline management don't see fit to mandate revision of the basics like this by and large, probably considering it too costly.
Respectfully disagree, in part.

What needed to be recalled from original PPL and ATPL certification was how to use and apply an instrument scan to inform control inputs to correct for out of parameters performance. That basic skill would have prevented the stall, and thus the need to step outside the box and handle stall recovery, versus stall prevention.

The evidence so far suggests to me the following: the pilot flying did not have a functioning instrument scan in progress. Had his instrument scan been functioning (see OODA comment above to PJ) he'd have made earlier and more fffective corrections to the nose attitude than he did.

Some evidence points to his colleague in the left seat having his scan working for a bit, based on the corrections he was calling for. Beyond that, I remain in the dark in re CRM, and how the second set of eyes and the second brain were not well used. I hope the final report can shed a bit of light, but I don't know if it will.

I hear music. I could swear that it is an overweight mezzo soprano singing, yet again the
Pitch and Power Chorus
from Wagner's opera, The Flight of Valkyrie 447's Gotterdamerung. :(

RetiredF4

7th May 2012, 19:41

Clandestino
Yes, combat pilots of last thirtysomething years usually do have a little gizmo making their life easier during approach and landing, it's either doughnut & chevrons type AoA indexer or AoA bracket on HUD.

and a gauge with an indicator where the needle points to the appropriate number, or on the hud an equivalent readout. Aditionally an aural tone in the headset, modulated in relation to the AOA.

Use during approach and landing is a side effect though, the primary task being ab le to maneuver at high AOA´s in a fast changing altitude and speed environment, where the speed indication tape as an performance instrument would be of less value.

Clandestino
It is there to make their already complicated life easier by reducing the need to accurately calculate their approach speed for actual weight plus any effect from external stores.

See above, true at least in the forces i served (german air force, USAF). If a fighter pilot would need relieve in calculating approach and landing speed, he better would be off flying as SLF. But it is useful in double-checking computed speed against AOA, and helps, that things are going right.

Clandestino
No, it is not 100% reliable as AoA vanes do get stuck or birdstricken then it's reversion to monsieur Pitot again.

It is susceptible to errors and failures like any system we use in our world, and nobody would get the idea to replace any of the existing gauges or systems. See it as an Add-on.

Clandestino
Of course, one has to be proficient in its use, which can only be achieved through practice. It is of utmost importance to know that yellow light means stick back, red stick forward, not the other way around.

Same as any system, with the difference, that a pilot can learn the use of an AOA gauge within 1 hour academic session (no more time was spent with us), and an ape could learn it in some days. It´s no magic and it doesn´t need permanent training. The availability and observability would be enough.

As the discussion about AOA (not the AOA gauge) from the beginning of this thread shows, it seems difficult to understand the physics and effects of AOA from those pilots, who have never seen an AOA indicator. On the other hand we can find in former and updated present procedures about UAS and upsets a lot of references to AOA without having that information readily available in the cockpit.

PJ2

7th May 2012, 21:37

Lonewolf_50;
IMO you can overlay the basics of the OODA loop to describe the use of an effective instrument scan.
Yes, I see what you meant, and concur with this.

One gets used to the different scan, (as compared to the "T"), very quickly - it's close enough that you can "gestalt" it, by which I mean, see "normal" and not the actual numbers until it varies slightly - it's also more efficient as much of the horizontal and vertical situation is built for you in the PFD and ND respectively, including a superb picture of the energy state of the aircraft.

I have little doubt that the right-side PFD and ND were functioning normally. There are no indications in any of the data that would lead one to conclude otherwise. That said, we don't know; - but much has already been drawn as "given" elsewhere through secondary evidential chains and there is no reason why such cannot be drawn here. Besides, there is no parallax and we know the left PFD and ND were functioning as was the ISIS horizon which is large and easy to read, (compared to the steam group in older A330's). There could be no doubt as to the pitch attitude of the aircraft and, prior to the stall warning then apogee, the rate of climb.

Also, groundspeed is provided on the top-left corner of the ND, and would have been available during the UAS event as both are IRS-driven. The TAS would not be available and wind information would be "NCD" and presented as three dashes on the ND. In addition, selection of the GPS Groundspeed is part of the UAS Drill.

2 . System Description
A. General
The IR portion is a strapdown inertial system which provides a quality
reference for attitude, heading (true and magnetic), angular rates and
accelerations.
The IR software also computes:
- the inertial position
- the ground velocity
- the baro inertial vertical speed
- the drift angle
- the wind
- the flight path data.

http://www.smugmug.com/photos/i-2VNtBx4/0/M/i-2VNtBx4-M.jpg

Lyman

7th May 2012, 23:09

One can assemble stretchers, splats, posts, rails, with hardware, a fabric mat, and sell it to the public, but they will see a "chair".

The "chair" is gestaltic, for "what becomes the whole....."

Likewise, as PJ2 says, and Lonewolf has offered, the "picture" is what we want.

The "Get", The "have", the understanding. It is not made up of individual parts, but the whole, only. One patterns the brain to then eliminate the pieces, and reduce the elements, until the whole is become unity. This is done by not relying on the traditional, but opening up the aware. 'Pattern Aware', if one wishes.

It used to be called the "Right Stuff". But that had more to do with attitude, and demeanor, which, though not unimportant, isn't the critical thing.

"Er, what are you doing...." Captain DuBois, upon entering the flight deck. He no doubt knew, in some fashion, else he would not have been so direct. One does not Command a wide body across the Oceans without some "Stuff". From what we have, we need to look at what we have, and I do not mean to be obtuse. I can with great reluctance concede a lack of "Stuff" from the F/Os, but not the Captain. And for the F/Os? Only with objection.

To paraphrase a Wannabe, "If a klutz like me can takeoff, recover from STALL and Land, then anyone can....."

The technicals are insufficient to condemn, all they open up is a frustration at not hearing the actual CVR. "What was that?" I would like to know, for I doubt seriously it was Robert rhetorically showing his 'klutz' re: the STALLWARN. Likewise, and this is important, It is not possible the crew was un aware of STALL. How can I say that? Because PJ2 has said the displays were consistent with the recovered data.

That cannot mean the displays were duff, only that PJ2 says they were golden. Fine, and I mean it. Is it possible that something unknown to the group here was occurring that prevented a standard solution, and there was insufficient time to implement a work around? Early on, a person who claimed to have heard the recording stated that the Captain said, beyond ...."doing?" "This is a STALL, get the (expletive) Nose Down."

Probably made up? We have not seen that report for some time, and it originated in the World of Journalism.....so.

Unless and until the complete CVR is heard, I hold my fire. I don't need to hear it, but some one does who has no agenda. If it is as bubbers44, 757 pilot says, "no professional pulls up into a STALL and falls into the SEA..." then I will choose another airline, one with friendlier skies than AIR FRANCE.... And possibly eschew the air, for SEA, in a slow boat.

Clandestino

7th May 2012, 23:12

Franzl, thank you very much for correcting and elaborating on my amateurish take on the use of AoA in fighters. Sowieso, I can't help noticing that you didn't address my fundamental objection: airliner pilots do not share military interest in AoA as we don't indulge in manuevers where AoA gauge is of utmost importance, such as maximum possible rate turns etc. You have flown your Rhino by reference to it, Airbus pilots fly their steed without reference to it. Horses for courses.

but, pray tell us, what are the advantages to the AB sidestick system if cost (weight savings) are removed as a factor? That is the only justification I've ever seen for such a design.Lesser complexity compared to yokes pretending they are doing something more then driving transducers. More cockpit space. Easier to get in and out of seat. Safer in incapacitation where unconscious pilot falls over controls.

Could we look at this more objectively?

>Sigh< We can try.

I'm aware that the 'low speed awareness' markings are fundamentally different from Airbus' markings of 'characteristic speeds'.Not valid for all Airbus characteristic speeds. Valpha max and Wsw on Airbus are very similar to low speed cue. ADC/IR design, flight controls and display architecture are different yet displayed information is similar.

But when airspeed has 'gone south' and in Alternate Law, may be the 'low speed awareness' is better? If airspeed is lost, how could we have possibly have low speed awareness? High alpha awareness is even better and is provided through aural stall warning.

While the speed tape is faulty (maybe it should be 'greyed'), the 'low speed awareness' tape is valid, correctly displaying the stall margin.Assumption too much, I'm afraid. It doesn't work that way on any tape ASI I'm aware of. I am sure that people designing, building and certifying those things know a whole lot more about them than two of us put together.

It would have informed the pilots of the 'validity' of the first brief stall warnings, that they were transient and no reason for concern at that timeAt the cruise Mach, they were not 'valid', they were valid. They were transient as the aeroplane was jerked into climb at its max recommended cruise level and were reason to be very, very concerned.

It doesn't have the big drawbacks of the BUSS that you lose all three ADR's for the remainder of the flight, and that it is virtually useless above (IIRC) FL250.That's putting the cart in the front of the horse; BUSS doesn't cause loss of all ADRs - it's the way around. As long as you have at least one valid ADR, you fly by it. You go to BUSS when all hope is lost that at least one ADR can be recovered.

No .. neither the BEA or DGAC for those on AF aircraft that were involved in this type of incidentHmmm... then who ordered replacing the pitots if no one was aware of the incidents? Back to PPRuNe: thirty-something crews goes through similar ordeal as AF447 without PPRuNe even noticing and now we have eighth thread on AF447? Aren't we indulging in a bit of outcome-based-analysis here?

What needed to be recalled from original PPL and ATPL certification was how to use and apply an instrument scan to inform control inputs to correct for out of parameters performance. That basic skill would have prevented the stall, and thus the need to step outside the box and handle stall recovery, versus stall prevention. Absolutely correct! That's the reason why other crews managed to save themselves, fly out of the trouble and no-one notices something weird goes on. IMHO, the idea that AoA gauge would have saved AF447 crew is unfortunately just wishful thinking. What are the chances that pilot who is unable to grasp the meaning of increasing attitude and altitude indications, therefore being unaware he's pushing aeroplane up where it just can't fly and finally displays paradoxical and provenly lethal reaction to stall warning, would pay heed to AoA gauge?

Old Carthusian

7th May 2012, 23:23

Retired F4
I see what you mean now - I was thinking of a different definition of expectation pattern. That you have a certain desire and when you move the controls you think that the aircraft will respond to your expectation no matter what the reality is. This seems to have been the situation of the PF. However, your instruments should still be your indicator of what your aircraft is doing.
With unreliable instruments there are SOPs and ways of analysing the issue. CRM is also a vital tool. Korean Airlines 8509 is especially relevant here as it demonstrates how to and how not to deal with unreliable instruments. But in the case of AF447 we have the PNF seeing from his instruments that something was amiss but taking no action. This indicates a breakdown in CRM which no yoke would have alleviated.

PJ2

7th May 2012, 23:39

Lyman;

Just to be precise, I don't mean anything complicated by the term, "gestalt"; if you fly lots of hours, you'll know what I mean.

Those who "wear" their aircraft when they strap it on know the sounds, the instrument readings, the vagaries and the "tune" of their machine and know instantly, before formal cognition, when something is amiss and they are already moving towards solutions even if such action is to wait...

The difficulty with digitizing an environment is that it becomes cold, aloof and analogically foreign to the mind. Digital readings require first an act of cognition then imagination, whereas old-fashioned guages always show "how much", and "how much too much/too little" without actually reading the guage first, because one knows "normal".

In a digital airplane, one can fly it without understanding it, mainly because one isn't actually flying it; the full-time automation is and we must build in substitutes for the experience of flying it, most of the time successfully. But the priority has shifted from knowing how to fly to knowing which mode to be in. This has been said many times here.

In the face of voluminous digitized automation, the task of cognition and imagination is monumental. This is as much a philosophical point as it is a psychological or merely ergonomical one.

While many will dismiss this as academic nonsense even though there is no such thing, this was the first, and instant impression I had when I first sat in the A320 in 1991 to learn how to fly it after having flown the B767, the L1011 and three steam airplanes before them. As I've posted many times, one gets used to anything if one does it long enough; it becomes as comfortable as an old shoe.

The thought occurred to me when I was uncomfortable in that first exposure to the A320, that we do not perceive digitally and so the cognitive processes required to understand the airplane and fly it well were/are subtlely different but the differences are masked by the enormous success of these aircraft and of brilliant automation solutions which work extremely well - I love these solutions but it took a while to known and trust them.

These aren't areas of frequent examination and I don't expect that to change nor do I expect much interest in the comment because "automation" is successful. But when things go pear-shaped, the character of failure and accidents changes and I think this is one reason why. I guess most just get used to it.