AF 447 Thread No. 11
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Controls AF447
I am very uneasy with the terms used in the discussions around the Airbus
when it went its way to the bottom of the Atlantic. That is as a power pilot I feel that way. I read, for example, the computer decides the rate of change of the elevator when commanded from the cockpit. And that in 2 seconds nose down stick, the elevator actually travels from 30 degr nose up to 20 degr nose up ! Should there not be a "panic button" that, when pressed, makes direct control inputs (or the computerised equivalent) possible.? The aircraft was flying fully nose up elevator (stick input as well) at low speed and, I would have thought that when a pilot pushes fully nose down, the bloody elevator WILL travel fully nose down in QUICK succession.!!! In my days of flying I had to use full controls on many occasions, both in normal and in spin or landing round-outs. Why must modern pilots be deprived of this when the sh"t hits the fan, as was the case with AF447 ? Is it possible that we rely too much on statistical probabilities and accept a certain failure rate as normal ? Sure, high speed aircraft and high weights etc play a part, but should the "feel" of flying manually not be exactly that in cases of emergency ? Control loss in the military and civilian aircraft do give a pilot in most cases the option to hit the silk ! Is it possible that (computer) engineers and software experts
have gone too far in taking control of controlling an aircraft ? And test pilots play by the company book so as to keep their well paying jobs ? Just asking.................
when it went its way to the bottom of the Atlantic. That is as a power pilot I feel that way. I read, for example, the computer decides the rate of change of the elevator when commanded from the cockpit. And that in 2 seconds nose down stick, the elevator actually travels from 30 degr nose up to 20 degr nose up ! Should there not be a "panic button" that, when pressed, makes direct control inputs (or the computerised equivalent) possible.? The aircraft was flying fully nose up elevator (stick input as well) at low speed and, I would have thought that when a pilot pushes fully nose down, the bloody elevator WILL travel fully nose down in QUICK succession.!!! In my days of flying I had to use full controls on many occasions, both in normal and in spin or landing round-outs. Why must modern pilots be deprived of this when the sh"t hits the fan, as was the case with AF447 ? Is it possible that we rely too much on statistical probabilities and accept a certain failure rate as normal ? Sure, high speed aircraft and high weights etc play a part, but should the "feel" of flying manually not be exactly that in cases of emergency ? Control loss in the military and civilian aircraft do give a pilot in most cases the option to hit the silk ! Is it possible that (computer) engineers and software experts
have gone too far in taking control of controlling an aircraft ? And test pilots play by the company book so as to keep their well paying jobs ? Just asking.................
Last edited by Yankee Whisky; 20th Jun 2013 at 23:42.
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Originally Posted by Yankee Whisky
And test pilots play by the company book so as to keep their well paying jobs ? Just asking.................
That applies also to the authority test pilots who examine an airplane presented for certification, although they do their work from a different perspective. D.P. Davies explains it nicely in his book HTBJ.
Last edited by HazelNuts39; 21st Jun 2013 at 07:49.
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The test pilots that I know don't fit your description. They chose their career out of love for flying, and enjoy being members of a team that develops these marvelous machines.
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I agree, I will have the pleasure to see Bob Hoover and Chuck Yeager at Reno again in September at the Reno Air Races. They are proof that test pilots are not, yes, company pilots but love what they do.
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Originally Posted by busTRE
Yeah, I said an airbus CAN stall in normal law!
I do mention the case where the system can be duped by exceptional conditions when inputs silently lie to that EFCS.
Originally Posted by Clandestino
Parbleu! Wasn't there any indication in cockpit something wasn't quite right?
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Originally Posted by Clandestino
Now, can we accept that alpha probes need to have some airflow to work reliably or do we keep on harping that they have to work perfectly from zero kt to Mmo, which is quite a wishful thinking?
Fictional software. As developed and certified - can't.
Not necessarily just because it's a FBW of different flavour. Part of it is certainly attributable to her price tag combined with date of service entry - she just didn't trickle down yet to lower tiers operators.
gums & USMCprobe: while the FPV points you both raise were of interest, the FPV equivalent (FD) wasn't working in that A330 when airspeed went unreliable. (That is how I understand the system. If I misunderstand, apologies for adding to the noise)..
Per HN39,
Comment for HN39:
Even the pilot in the left seat seemed concerned by the right seat pilot' climb. (Per CVR in report)
AZR:
So long as the pilots both know how the system works, and have practiced it (see BOAC's "properly trained" point) the law degradation slope makes sense (to me) when one looks at the system as a whole. The training point, the training objecive, would hopefully include knowing your systems and sub systems well, and be able to apply the following trouble shooting approach:
"If this is what's wrong, and these lights/alerts are going off, this is what the plane is doing or about to do, or not doing ... "
Being unable to determine "what's it doing" based on "this is what's wrong" opens a crew up for errors in remedy for a malfunction. (True for a lot of different aircraft and situations)
NTA:
Ever since the release of the FDR info during the interim report era, that question has been foremost. The answer lies in the realm of post hoc mind reading, or best guess speculation.
We aren't ever going to know, but we can infer a breakdown of the instrument scan of both the pilot at the controls, and his co pilot.
One of the better guesses is that PF was following the FD, at least for a while, which he didn't realize was going wrong ... which it will do when airspeed goes all wrong, as at the initiation of the event.
henra:
Might this lead one to label the event as being the result of "confusion" rather than "mode confusion" ... I'd better duck ...
Barking:
The "uphill walk" might have informed his initial verbal offering of "What are you doing" as he arrived on scene in the cockpit.
jejeant:
So, where was he -- in the lavatory?
HN39:
Back to an early discussion on training, recency of training, and BOAC's point on "properly trained" pilots. Seems a decent estimation.
Per HN39,
I've no experience with FD's but note that they were mostly unavailable in the first 40 seconds of the zoom-climb, and locked on to 6000 fpm V/S then 1400 fpm only after the pilot commanded those RoC's apparently independently of the FD's.
I just can't see any reason for him to zoom-climb to seek the limit of envelope protection.
AZR:
OK, thanks for clarifying that for me. I agree that a law reversion is "something more" to take into account for the crew, but I believe that the advantages of normal+alternate+direct laws are more important than the disadvantages (including the quite possible but not proven 'mode confusion').
"If this is what's wrong, and these lights/alerts are going off, this is what the plane is doing or about to do, or not doing ... "
Being unable to determine "what's it doing" based on "this is what's wrong" opens a crew up for errors in remedy for a malfunction. (True for a lot of different aircraft and situations)
NTA:
If they had an attitude indicator. why are we here?
If the A/H was operational, then, why did they not look at it?
If the A/H was operational, then, why did they not look at it?
We aren't ever going to know, but we can infer a breakdown of the instrument scan of both the pilot at the controls, and his co pilot.
One of the better guesses is that PF was following the FD, at least for a while, which he didn't realize was going wrong ... which it will do when airspeed goes all wrong, as at the initiation of the event.
henra:
A/H that is called PFD.
There is also not the slightest indication it didn't work correctly. Please don't let us go back to that tinfoil hat discussion.
It just seems what they saw didn't ring a bell?
There is also not the slightest indication it didn't work correctly. Please don't let us go back to that tinfoil hat discussion.
It just seems what they saw didn't ring a bell?
Barking:
Can anyone explain why Monsieur Le Capitain did not notice an unusual deck angle during his sprint to the flight deck? Any of us who've walked in the aircraft during initial climb, especially on empty positioning sectors as pax, have been aware of the deck angle and the extra effort to walk uphill.
jejeant:
I have always suspected that the captain was not in the rest accommodation
HN39:
The flight director displays could have prompted him to command a positive pitch angle, of about 15°.
This value is the first option in the UAS procedure for the take-off phase below thrust reduction altitude.
It is possible that, even though he did not call it out, the PF had recalled this memorised value and then had clung to this reference without remembering that it was intended for a different flight phase.
The conjunction of this remembered value and the flight director displays may have constituted one of the few (and maybe even the only) points of
consistency in his general incomprehension of the situation.
This value is the first option in the UAS procedure for the take-off phase below thrust reduction altitude.
It is possible that, even though he did not call it out, the PF had recalled this memorised value and then had clung to this reference without remembering that it was intended for a different flight phase.
The conjunction of this remembered value and the flight director displays may have constituted one of the few (and maybe even the only) points of
consistency in his general incomprehension of the situation.
Last edited by Lonewolf_50; 24th Jun 2013 at 16:37.
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So, where was he -- in the lavatory?
For me the PNF left seat telling PF to stop climbing several times was the probably the most puzzling data point.
If the guy next to me is repeatedly non-responsive and executing a dangerous change in flight level then it ones duty "I have control" and press priority button, and I expect some confirmation in response "roger, you have control" or whatever the French equivalent is.
It was clearly time to put their game face on and switch from sloppy banter chat to professional communications.
Who knows maybe they were impaired by fumes/gas - this is not a judgement just an observation.
Last edited by xcitation; 25th Jun 2013 at 23:07.
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Yes, a pilot monitoring is supposed to make sure the aircraft is handled properly. He didn't so everybody died. The PF did everything wrong and pulled up into a full stall with PM letting him. Unless airlines get better FO's this will continue to happen. The captain is required to take his rest break so make sure the two pilots up front know what they are doing. These two didn't have a clue because they were autopilot monitors and couldn't hand fly their aircraft, only the captain could who was on his break.
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Yes, a pilot monitoring is supposed to make sure the aircraft is handled properly. He didn't so everybody died.
Over in the R&N Memmingen thread a couple of days ago, Yankey Whiskey made mention of "gliding experience" being possibly a prerequisite in preparing pilots in how to handle the 'too fast and high' events. I responded with reference to this AF447 event by pointing out that this PF did have gliding experience, but take heed of what he did. Neither did the PNF do what you have suggested he should have.
Both posts were deleted.
Their presence in that thread was likely at odds with an otherwise seemingly rational discussion on CRM and how it should be handled in an approach to a possible TOGA situation.
Edit:: The last two paragraphs are not factual! My recollection of when I made the post was somewhat confused by something ...
Last edited by mm43; 27th Jun 2013 at 02:28. Reason: withdraw comments re deletion of posts
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I responded with reference to this AF447 event by pointing out that this PF did have gliding experience, but take heed of what he did.
and not touched the controls
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If you touch the controls do something positive to fix the situation. Since they forced a full stall they would have been better off both leaving the cockpit and waking the captain to fix things. At least when he arrived at the cockpit he would have something recoverable to deal with instead of what they left him with in the last minutes.
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If you touch the controls do something positive to fix the situation. Since they forced a full stall they would have been better off both leaving the cockpit and waking the captain to fix things. At least when he arrived at the cockpit he would have something recoverable to deal with instead of what they left him with in the last minutes.
Personally I think that PM was aware of PF's efforts at keeping the wings level, and did not feel confident enough in his own abilities to take over faced with his lack of understanding as to why the aircraft was so goosey in roll.
The initial significant roll oscillation stands out as an unusual situation not described (to the best of my knowledge) by the other aircraft that had experienced multiple ADR failures due to pitot icing. The limited training these two copilots received did not prepare them for flight in ALT2B Law.
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Originally Posted by Yankee Whisky
The aircraft was flying fully nose up elevator(stick input as well) at low speed and, I would have thought that when a pilot pushes fullynosedown,thebloody elevator WILL travelfullynose down in QUICK succession.!!! In my days of flying I had to use full controls on many occasions, both in normal and in spin or landing round-outs. PWhy must modern pilots be deprived of this when the sh"t hits the fan, as was the case with AF447 ?
Despite Airbus is using the word "protection" against excessive g (2.5!!!) I suspect the idea was to increase passengers comfort in LIGHT TURBULENCE holding g to 1... In the 80's automation fashion started to have interest to limit sound or vibration with "bruit blanc".
Using the feedback to maintain g to 1 was such a path to realize that goal : limit oscillation of the airliner. (In which point of the plane is a second problem...)
But when the system is piloting z`` with feedback you have to use the stick not to control the elevator but the tendance of the elevator (Airbus S/S action)and you have to integrate the signal in the direct path. The pitch trim does the same work to maintain g=1, not the speed, and is "protecting" (limiting) against quick full nose down.(not a god idea!)
Last edited by roulishollandais; 27th Jun 2013 at 11:20.
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what would have prevented the aircraft from rolling over onto its back, particularly since it had a significant tendency to roll to the right in its ALT2B mode?
http://www.bea.aero/fr/enquetes/vol....gure.64.en.png
Roll attitude: the pink line in chart above shows no roll over - only constant roll approx 10-15 deg. Now compare pink to red and blue and you see oscillations appear to be mostly pilot induced. I suggest that the airbus damps the roll disturbances very well on its own probably because of its mass and drag in the roll axis.
Last edited by xcitation; 27th Jun 2013 at 15:21.
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From the AF 447 Archives
Original quote posted by Lonewolf_50
Hmmm, I don't think that's what the "do nothing" proponents are suggesting.
Hmmm, I don't think that's what the "do nothing" proponents are suggesting.
Original posting by PJ2: I wrote on July 30th, 2009 that the correct response was to "do nothing". I don't claim any special prescience...it's just the logical thing to do when in cruise. When this entire matter was conflated in subsequent discussion, I argued that the memorized items were not only confusing but the entire drill and checklist were poorly written. The "above FL100" memorized item to pitch to 5deg and set CLB thrust was, in my view, intended to cater to high density altitude airfields, not cruise altitudes. But this is not clear in the drill.
There has been plenty of discussion on this item throughout these threads, and I suggest the use of mm43's excellent PPRuNe search tool, to find these discussions.
The BEA press conference comment is, in my view, incorrect. While control would not be lost with an increase of pitch of 2.5deg to an attitude of 5deg, (because the pitch is already 2.5deg in cruise, roughly), the maneouvre does de-stabilize the aircraft when the aircraft is already stabilized in level flight with a good pitch attitude and power setting which were just fine moments before the UAS event. In fact, if one is not trained or accustomed to high altitude handling of a transport aircraft, one may be hunting a great deal with either a CC or an SS to maintain a pitch of 5deg. I just can't see, and never could see this memorized item making any sense whatsoever when in cruise flight.
There has been plenty of discussion on this item throughout these threads, and I suggest the use of mm43's excellent PPRuNe search tool, to find these discussions.
The BEA press conference comment is, in my view, incorrect. While control would not be lost with an increase of pitch of 2.5deg to an attitude of 5deg, (because the pitch is already 2.5deg in cruise, roughly), the maneouvre does de-stabilize the aircraft when the aircraft is already stabilized in level flight with a good pitch attitude and power setting which were just fine moments before the UAS event. In fact, if one is not trained or accustomed to high altitude handling of a transport aircraft, one may be hunting a great deal with either a CC or an SS to maintain a pitch of 5deg. I just can't see, and never could see this memorized item making any sense whatsoever when in cruise flight.
PJ2 post continued:
At cruise altitudes, I have argued that this was no emergency at all, it was an abnormal which required standard responses as trained, and which required no action other than to get out the QRH checklist for the pitch and power settings. Most here disagreed with this view, citing the "Above FL100 decision-point, but frankly there is no way that setting 5deg pitch is indicated in cruise.
Whether this PF intended to set 5deg or 15deg or something else cannot be factually determined at this time. But the airplane pitched up, and it was held there until the stall while both pilots accepted the trajectory, the pitch attitude and the loss of energy. We can only surmise why, and that, is, I think hindsight territory
At cruise altitudes, I have argued that this was no emergency at all, it was an abnormal which required standard responses as trained, and which required no action other than to get out the QRH checklist for the pitch and power settings. Most here disagreed with this view, citing the "Above FL100 decision-point, but frankly there is no way that setting 5deg pitch is indicated in cruise.
Whether this PF intended to set 5deg or 15deg or something else cannot be factually determined at this time. But the airplane pitched up, and it was held there until the stall while both pilots accepted the trajectory, the pitch attitude and the loss of energy. We can only surmise why, and that, is, I think hindsight territory
There were considerable discussions regarding the state of mind of the PF & PNF:
Original posting by PJ2
Quote:
Ah, but was it surprise or "startle" which affected the PF, or was it abject fear?
Either can be argued but in doing so think about what is being said. What business has "abject fear" got in possessing a crew under the quite normal-for-the ITCZ circumstances faced that night and a system failure which, while disconcerting and even initially confusing, was neither an emergency nor as I say a massive failure of engine or aircraft structure? Why abject fear? Startle yes, but then an automatic response? My question is, what must be assumed for such an answer to be rational and in keeping with all those goals we hold dear?
A rapid decompression would certainly startle someone!, and the drill is there to do. Here, there was nothing to indicate a requirement for immediate action.
I want to be careful here not to portray this up as "judge-and-jury" discussion - it is not. It is an attempt by one experienced captain among many here, to keep the original question open rather than "answering" it with, "it was 'startle' factor, and therefore we need to train that out of pilots".
My point is, surprise notwithstanding, (been there a few times...with adrenaline), the intent of thorough training and flying transport aircraft with experienced crews is discipline when things go wrong, reversion to known responses and effective crew communication and why that didn't occur here. The BEA Report goes as far as it might in my view in answering this question but it isn't a complete answer. I think that is for the industry at large to answer, as per the larger discussion concerning automation and "wither airmanship?" I'm not dismissing the startle response - that would be silly. I am asking for some careful thought before assigning it.
Quote:
Ah, but was it surprise or "startle" which affected the PF, or was it abject fear?
Either can be argued but in doing so think about what is being said. What business has "abject fear" got in possessing a crew under the quite normal-for-the ITCZ circumstances faced that night and a system failure which, while disconcerting and even initially confusing, was neither an emergency nor as I say a massive failure of engine or aircraft structure? Why abject fear? Startle yes, but then an automatic response? My question is, what must be assumed for such an answer to be rational and in keeping with all those goals we hold dear?
A rapid decompression would certainly startle someone!, and the drill is there to do. Here, there was nothing to indicate a requirement for immediate action.
I want to be careful here not to portray this up as "judge-and-jury" discussion - it is not. It is an attempt by one experienced captain among many here, to keep the original question open rather than "answering" it with, "it was 'startle' factor, and therefore we need to train that out of pilots".
My point is, surprise notwithstanding, (been there a few times...with adrenaline), the intent of thorough training and flying transport aircraft with experienced crews is discipline when things go wrong, reversion to known responses and effective crew communication and why that didn't occur here. The BEA Report goes as far as it might in my view in answering this question but it isn't a complete answer. I think that is for the industry at large to answer, as per the larger discussion concerning automation and "wither airmanship?" I'm not dismissing the startle response - that would be silly. I am asking for some careful thought before assigning it.
Original posting by PJ2
The "better way" is in how the response was made right from the start of the event. The SOPs do not change significantly from type to type. The trained crew response to an emergency or an abnormality is, with minor variations throughout the industry, very clear and very specific:
- Take control of the aircraft, (usually the PF) and ensure stable flight and navigation;
- Communicate: PF announces the emergency/abnormality so the other crew member, (PM), is aware and shifts thinking and priorites to the emergency/abnormality, (where applicable, PF takes radio communications responsibilities);
- PF calls for the "ECAM Actions" first, then the QRH checklist where applicable;
- PM executes/completes ECAM actions, clearing messages as they are completed;
- When finished, PM calls "ECAM Actions Complete" and calls up the Status Page for aircraft and system condition review;
- When aircraft/system Status is reviewed, PF calls for any applicable QRH checklists. For example, sometimes landing data requires modification;
- Secure the aircraft for continued flight or diversion;
- Communicate with ATC, F/A's (through their leader) and company dispatch;
- Passenger announcement, if required;
- Monitor changes in aircraft performance, fuel situation etc, as required.
The "better way" is in how the response was made right from the start of the event. The SOPs do not change significantly from type to type. The trained crew response to an emergency or an abnormality is, with minor variations throughout the industry, very clear and very specific:
- Take control of the aircraft, (usually the PF) and ensure stable flight and navigation;
- Communicate: PF announces the emergency/abnormality so the other crew member, (PM), is aware and shifts thinking and priorites to the emergency/abnormality, (where applicable, PF takes radio communications responsibilities);
- PF calls for the "ECAM Actions" first, then the QRH checklist where applicable;
- PM executes/completes ECAM actions, clearing messages as they are completed;
- When finished, PM calls "ECAM Actions Complete" and calls up the Status Page for aircraft and system condition review;
- When aircraft/system Status is reviewed, PF calls for any applicable QRH checklists. For example, sometimes landing data requires modification;
- Secure the aircraft for continued flight or diversion;
- Communicate with ATC, F/A's (through their leader) and company dispatch;
- Passenger announcement, if required;
- Monitor changes in aircraft performance, fuel situation etc, as required.
Hope the above is helpful and appropriate in the current ongoing discussions...
TD
It is not a Pitts or an Extra.
I don't think it will bank by itself much over 30°. Maybe 45°. With increasing bank angle you get sideslip. In that conditon dihedral and winglets will start creating an opposing force.
I would expect a spiralling decent. Mmo could potentially become an issue in such a Situation but drag also increases drastically when Approach Mmo.
I'm with bubbers44 on this one. Chances are he would have found a controllable yet maybe banking/descending aircraft.
Last edited by henra; 27th Jun 2013 at 18:23.
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Auto Call
Would it be easy to have the a/c auto alert an emergency operations center of a stalled a/c at cruise altitude?
Ground support would then call the flight deck using the sat phone to establish a dialogue whilst reviewing the basic flight data via telemetry. There would be a lag of a couple of seconds in the comms however it might restore calm to the flight deck and remind them of SOP.
This would not require any new equipment or expense, probably just a simple software tweak and setting up an emergency ops center. UAVs and remotely piloted a/c require far more sophisticated software.
Then again perhaps the lawyers have blocked this already because of the liability.
Ground support would then call the flight deck using the sat phone to establish a dialogue whilst reviewing the basic flight data via telemetry. There would be a lag of a couple of seconds in the comms however it might restore calm to the flight deck and remind them of SOP.
This would not require any new equipment or expense, probably just a simple software tweak and setting up an emergency ops center. UAVs and remotely piloted a/c require far more sophisticated software.
Then again perhaps the lawyers have blocked this already because of the liability.