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AF447 wreckage found

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AF447 wreckage found

Old 18th Aug 2011, 06:54
  #3021 (permalink)  
PJ2
 
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Originally Posted by GerardC, Post #3020
Well... not really. According to AF book (see BEA's report appendix 9), when ALL IAS are unreliable "sécurité du vol" must be considered "affectée" and 5° NU/TOGA drill MUST be performed.
I don't read or speak French. If I may, could I ask that the paragraph beginning with the statement, "Si la sécurité du vol est affectée", be translated? I would like to understand exactly what it is saying. Specifically, I would like to know where it says, "and 5° NU/TOGA drill MUST be performed." Thanks very much.

In the UAS drill's design, the memorized items are for when the crew doesn't have time to look up the pitch and power, and instead must react very quickly, for example on takeoff. Remember, this drill has evolved from the original ones written a few years after the Birgenair and Aeroperu accidents.

When in stable cruise flight at FL350, a loss of any or all airspeed indications is not an emergency like the loss of engine thrust, loss of cabin pressure or a fire warning. One is not required to instantly act and "do something".

I think a mandatory pitch of 5degrees at cruise altitude if the airspeed is suddenly unreliable is a serious error in checklist design and the wrong guidance to the response given what would result if one pitched the aircraft from 2.5deg to 5deg.

The result would be destabilizing because level flight has been lost in the resulting climb and there is no longer any pitch and power reference with which to stabilize the speed because 5deg NU is going to cause a loss of energy/speed and if one is pitched up, one has no idea what one's speed is regardless of the power setting. At cruise altitude, there isn't much reserve power and pitch attitudes for most climbs when changing altitudes are usually a half to one degree higher than cruise pitch. A 2.5degree increase in pitch is huge.

Further, if the memorized drill requires "5deg" when the aircraft is clearly above both the MSA and circuit altitude" (the last memorized item in the box), then the drill is open-ended and does not provide for a level-off point from which to troubleshoot. It might be argued that at some point a crew flying this airplane, knowing that it is losing speed and energy, (one would hope they knew!), would level off because the result of a continued pitch-up is obvious. Of course, that then begs the question of the mandatory pitch-up in the first place, does it not, so why would anyone ever do it?

I think that if a mandatory pitch-up to 5deg whenever the aircraft is above FL100 which may have been the last training on this abnormal that the PF had received, then perhaps we have the reason why the PF pitched up almost instantly, and unannounced to the PNF, upon the loss of the speed indication. But I can't for the life of me really believe that that is what the drill means or requires, is it?

Pitching the aircraft up like that rather than maintaining level, stable flight is a guaranteed loss of situational awareness and potential loss of control as happened here, whereas maintaining level flight with pitch and power settings "as they were", keeps all factors in the "known" territory while the speeds sort themselves out.

I don't understand why two things aren't abundantly clear to everyone upon pitching up to 5deg - a) what the airplane would immediately do, and b) regardless of the memorized items which would mostly be applied during takeoff or early in the climb, why is there any support at all for a pitch-up to 5deg at cruise altitudes, when the outcome of such a manoeuvre is quite clear?

The question might be rephrased thus: Do we follow a bad checklist and place the flight at serious risk or are we pilots who think and fly to stay alive?

It isn't complicated and it certainly wasn't an emergency requiring the instant action that occurred.

Last edited by Jetdriver; 18th Aug 2011 at 08:26.
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Old 18th Aug 2011, 07:49
  #3022 (permalink)  
 
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@PJ2 and "machin" : to clarify.

"Si la sécurité du vol est affectée (toutes les indications de vitesse sont erronées ou si l'indication de vitesse fausse ne peut être clairement identifiée)...appliquer la procédure suivante
- appliquer les actions immédiates (équivalent de la maneuvre d'urgence)...

-AP/FD.....OFF
-A/THR.....OFF
[....]
Au dessus (above) FL 100
Poussee/assiette...CLB/5° (up)"
(Bold is from AF book)

"If flight safety is an issue (all IAS unreliable OR if unreliable AS indication is not clearly identified)... apply thereafter procedure : (same as unreliable IAS drill : AP/FD/ATHR OFF ; CLB thrust/5° NU).

I am not saying this is a smart idea, I am just saying that, from a notary/Court point of view : AF book mandates "AP/FD/ATHR OFF ; CLB thrust/5° NU" each time ALL IAS are unreliable or if THE unreliable/faulty IAS cannot be "clearly" identified
Any one of these two conditions is considered to be "affecting flight safety".

Last edited by GerardC; 18th Aug 2011 at 08:07.
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Old 18th Aug 2011, 07:52
  #3023 (permalink)  
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GerardC;
I am just saying that, from a notary/Court point of view : AF book mandates "AP/FD/ATHR OFF ; CLB thrust/5° NU" each time ALL IAS are unreliable or if THE unreliable/faulty IAS cannot be "clearly" identified
Any one of these two conditions is considered to be "affecting flight safety".
Okay, thanks very much.

Wow.
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Old 18th Aug 2011, 08:13
  #3024 (permalink)  
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"If you read carefuly BEA's reports you will notice that most (if not ALL) affected crews wisely decided NOT to apply the 5° up/TOGA drill"
Nevertheless, that - 'apply TOGA power and seek to maintain altitude' - was the 'book procedure' (for both Airbus and Boeing) at the time AF447 went in? It was changed to 'get the nose down and apply power sparingly as the attitude improves' - a few months after AF447; can't myself believe that that was just a conicidence, and had no connection with the accident (plus the 2008 Perpignan one)?

PNF knew what PF was doing, there was no mystery. It is a fairytale. He was constantly scolding the PF to descend. And probably not from looking at the ss.
Except, though, that he could only get that information from the instruments? First of all there'd have been a 'timelag' - and secondly, given the abnormal conditions etc., he couldn't have been 100% certain that it was the result of the PF's inputs? I remain of the opinion that if he'd known about the stick inputs 'at first-hand' he'd have had a better (and earlier) chance to intervene decisively?

In any case, we haven't had much discussion of the fact that about halfway down the pilot (or 'pilots') DID make some nose-down inputs; and both the attitude and the airspeed improved. Because of the increased IAS, though, these inputs resulted in the 'dormant' stall warning waking up and sounding again. This is the point that the pilots' union is stressing - it very probably just served to make the pilots (all three of them by that time) even more confused......?

Finally there's the question of the THS staying at 'full up.' BEA barely mentions this fact in the AF447 report, but they covered it very well in their report on the (similar) Perpignan crash the previous year. That report very clearly explains why that happened:-

"Footnote:- The elevators must go beyond the neutral position before the auto trim function adjusts the position of the stabilizer.

"When the stall warning sounded, the Captain reacted by placing the thrust levers in the TO/GA detent and by pitching the aeroplane down, in accordance with procedures.

"The nose-down input was not however sufficient for the automatic compensation system to vary the position of the horizontal stabilizer, which had been progressively deflected to the pitch-up stop by this system during the deceleration."
As I understand it (given that the THS was at 13 degrees up) a very decisive nosedown input would have been required to get the THS moving down again; and even if one had been applied, let's not forget that the THS took a full minute to go from 3 degrees to 13 degrees; so, presumably, it would have taken another full minute to go down to a reasonable angle again?

Sadly, I'm not sure that the flight crew had as much as a minute of life left to them by that stage?

Furthermore, that report goes on to say:-

"Under the combined effect of the thrust increase, the increasing speed and the horizontal stabilizer still at the pitch-up stop, the aeroplane was subject to pitch-up moment that the Captain could not manage to counter, even with the sidestick at the nose-down stop."
Full Perpignan report can be read here:-

http://www.bea.aero/docspa/2008/d-la...a081127.en.pdf

So it appears that the BEA considered that the 2008 Perpignan captain had no practical chance of regaining control, even with full nosedown inputs? Yet, in the AF447 report, the BEA says that the AF447 2009 situation (in exactly the same circumstances, in a deep stall with the THS full up) was 'recoverable'?

I can't overly blame Airbus for trying to offload as much liabilty as they can; that's the way business works, especially with hundreds of millions in compensation at stake. But I hope very much that they will act quickly and decisively 'behind the scenes'; as I believe that they already have by changing the stall recovery procedure.

In particular, I hope that they:-

1. Link the sidesticks at least to the point that both pilots are aware of inputs on either side;

2. Review the operation of the stall warning; ideally, if technically possible, add a second warning reacting to an actual stall rather than an imminent one;

3. Make sure that, in future, if the rest of the aeroplane 'gives up' and hands the pilots manual control, the THS does the same.

My guess is that none of those changes would cost a great deal; they'd mainly be 'software' rather than 'hardware.' Additionally, they could be introduced quite quickly, on existing aeroplanes as well as new ones. Furthermore, I don't see any way in which those changes would make the aeroplanes any more difficult to fly; and they sure MIGHT help to avoid further such accidents in the future?








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Old 18th Aug 2011, 08:16
  #3025 (permalink)  
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PJ2 - whatever you think of the "5 deg nose-up" it would not have killed all. The a/c would have flown reasonably happily while the UAS drill was actioned. Any stall warning that might have been thus induced could have been actioned as normal.

What the focus needs to be (apart from stall recovery training, of course) is why the pitch went from 0 deg to 11deg.
Originally Posted by RWA
So it appears that the BEA considered that the 2008 Perpignan captain had no practical chance of regaining control, even with full nosedown inputs?
- this is not in fact the case. He had roll available. A perfectly 'practical' way to get the nose down and should be taught during 'unusual attitudes'.
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Old 18th Aug 2011, 09:44
  #3026 (permalink)  
 
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Experiance and Training of the Pilots

The BEA report has some of the flying backgrounds of the three AF447 pilots. None of the three had been military pilots, and it's possible the two younger pilots had only flown whatever automated equipment Air France put them in. I don't know if you needed a PPL to train as a pilot for Air France, when the two co-pilots trained (Ages 37 and 32). I think Air France trains it's own pilots. Not sure if either one had so much as soloed in a 152. Maybe some of you guys know?
The Captain started out as a flight attendant with Air France, then trained as a pilot.
The apparent lack of leadership, airmanship, and teamwork heard on the CVR made my curious about the background of these pilots. The PNF calling the captain back anxiously, make it seem as if neither co-pilot knew how to fly in the aircraft in the situation they found themselves in, and the PNF knew it.
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Old 18th Aug 2011, 10:49
  #3027 (permalink)  
 
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lyman,pls answer a single question.just yes or no

do you believe,every pilot inthe whole wide world,capable of flying an jet
a/c would after a/p disconnect had put the a/c in a climb of 7000ft/m ?



yes or no ?
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Old 18th Aug 2011, 11:50
  #3028 (permalink)  
 
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O/T: MPL Training...

The lack of hand-flying experience was discussed a page or so back... some of you here are Captain's seeing new F/Os. Have any here experienced crew trained according to the (relatively) new MPL licensing scheme? These crew will NOT have necessarily been through what I would call the conventional PPL -> etc route, and may have "learned" to fly in a simulator. Entirely.

If I understand the MPL correctly, an F/O may be in the right-hand seat on a fare-carrying loaded commercial flight after no more than a total of 12 take-off and landings (of which 6 can be in a simulator...).

What hope is there given that level of experience?
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Old 18th Aug 2011, 12:45
  #3029 (permalink)  
 
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Just had another look at the third report and was struck by how hard the PF appears to be working the roll axis right after the disconnect. See page 29..

http://www.bea.aero/docspa/2009/f-cp...90601e3.en.pdf

In the 30-35 seconds following the AP disconnect he made 17 more or less alternate roll inputs with the aircraft rolling 10 degrees first one way then the other. Was he simply too busy or too focused on roll to notice he was climbing ?
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Old 18th Aug 2011, 13:08
  #3030 (permalink)  
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Quoting philip2412:-

"do you believe,every pilot inthe whole wide world,capable of flying an jet
a/c would after a/p disconnect had put the a/c in a climb of 7000ft/m ?"

Welcome, philip2412.

But as to your question, it remains by no means certain that the climb was caused by pilot inputs. Please refer to Page 111 of the BEA's third report:-

http://www.bea.aero/docspa/2009/f-cp...90601e3.en.pdf

This shows that, at the time the THS started moving and the sudden climb commenced, the PF was applying relatively small movements, up or down - largely consistent, in my less-than-expert view, with an attempt to 'fly pitch and power.' However, the THS was already well on its way to 'full up.'

Agreed, the PF later applied TO/GA and a lot of noseup - presumably in response to the stall warnings. But by that time the aeroplane was ALREADY in a steep climb that, on the available evidence, had been commanded not by the PF but by the THS.

For confirmation, it's worth mentioning that, if you look further down the table, you'll see that the increase in the angle of attack from the point the THS began moving appears EXACTLY to parallel the THS's progress towards 'full up'........ and started long before the PF applied full noseup stick.

I'm prepared to accept that the pilot(s) could, arguably, have made a better job of attempting to recover. But I'm not at all sure that 'pilot error' caused the initial steep climb. Indeed, on the (limited) available evidence, it appears to have been the THS that started it, not the PF.......

Last edited by RWA; 18th Aug 2011 at 13:28.
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Old 18th Aug 2011, 14:21
  #3031 (permalink)  
 
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I can't believe that this drivel is still going on....

Face it. The 2 co-pilots porked up in spades. The PF's agricultural flying commanded the THS - it did what he'd erroneously commanded. He then failed to understand that he'd stalled the aircraft through incompetent handling.

Poor system knowledge, lack of awareness and no idea of basic principles.

But why on earth the captain decided to go and sleep before the aircraft was clear of the known serious weather forecast for the route....

Air France arrogance and their unwillingness to face the consequences of inadequate training on a complex aeroplane seems to me to be a contributory factor.
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Old 18th Aug 2011, 14:29
  #3032 (permalink)  
 
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While the devil's often in the detail, BEagle, I'm inclined to agree with you. Seems to me that some posters would have spent considerable effort trying to blame the iceberg for the sinking of the Titanic.
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Old 18th Aug 2011, 14:38
  #3033 (permalink)  
 
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I'll try again to frame what I see is the beginning of the confusions in this place.

What was assiete at 2:10:03? We know the Pitch of this a/c at 2:10:05 was 0 degrees. Knowing this would give a rough 'trend'.

Because here's the deal: After taking controls (after 2:10:05) the Pitch actual of the a/c is ? Trending ?

A normal cruising PITCH value would be ~2.5 degree?

If we consider that this a/c was @ PITCH lower than expected and perhaps trending even lower when a/p was lost, called into question is the perhaps not too relevant "Book".

What does the "Book" have to say about this?

Throughout, I see this "Book" as simplistic in nature. It assumes straight and level, unaccelerated flight?

Some say that the pilot should have done nothing by way of maneuvering.

NOT FAIR. The airframe was assumed to be active; sit still and watch the nose drop further?

Or "SET 5 degrees PITCH and CLB THR." Sorry, also not pertained.

That is a COMMAND to maneuver, quite possibly.

Consider: A "proper" PITCH command by the PF could have involved a PITCH excursion of as much as 6 degrees, perhaps a bit more.

The a/c did not immediately climb. What shall he do? Likely wait and see what his initial stick produced? From the Traces, I think that is what he did. I will forgive this gent some anxiety, and perhaps that, brand new to the grip with a/p loss, he is NOT conversant completely with Neutral Point. Throw in a proven wing drop that the a/p quit on, OK?

Rolling, Nose Low, Cavalry Charge, Master Caution, etc.

Not an Emergency? Like DePressurization? hmmm.......... The "Book" calls the loss of the AutoFlight system an "UPSET".

In what language is "UPSET" not an emergency?
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Old 18th Aug 2011, 15:08
  #3034 (permalink)  
 
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Someone mentioned that the js may have been occupied at the time.By the PF's better half.Has this been proven one way or another(CVR)?

Here are 2 relatively inexperienced co-pilots with no clear chain of comand order left by absent skipper.What dynamic would the presence of a 3rd party,especially a spouse or relative,have on this democratic mess?People act differently when theyre being watched than when alone.What led PF to over-react to a relatively benign situation(AS loss for 50 secs) and why didnt PNF intervene if he knew,as Lyman keeps saying he did,what was going on?Was it just atrocious flying skills or is there something else here as well?
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Old 18th Aug 2011, 15:20
  #3035 (permalink)  
 
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To be clear, the Sidestick visibility issue is not involved in my saying PNF knew. I base it on what the PNF said to PF, and what I know of French culture, not necessarily cockpit culture. One never prompts, or interrupts with critique, another's efforts. For PNF to have done so shows me he was elevated to that concern. Also not elevated sufficiently to remove PF from Stick control. In the middle. That way lies confusion. No command ethic should be operated as a democracy, certainly. This does not foreclose teamwork. Who would confuse democracy anyway with teamwork?
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Old 18th Aug 2011, 15:38
  #3036 (permalink)  
 
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Nz Law (active in NORMAL & ALTERNATE)

CHARACTERISTICS IN PITCH

IN FLIGHT

When the PF performs sidestick inputs, a constant G-load maneuver is ordered,
and the aircraft responds with a G-Load/Pitch rate.
Therefore, the PF’s order is consistent with the response that is "naturally"
expected from the aircraft:
Pitch rate at low speed; Flight Path Rate or G, at high speed.


• The aircraft maintains the flight path, even in case of speed changes
• In case of configuration changes or thrust variations, the aircraft
compensates for the pitching moment effects.
• In turbulence, small deviations occur on the flight path.
However, the aircraft tends to regain a steady condition.


AIRBUS PITCH CHARACTERISTIC
Operational Recommendation:

Since the aircraft is stable and auto-trimmed, the PF needs to perform
minor corrections on the sidestick,
if the aircraft deviates from its intended flight path.
The PF should not fight the sidestick, or overcontrol it.
If the PF senses an overcontrol, the sidestick should be released.
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Old 18th Aug 2011, 16:03
  #3037 (permalink)  
 
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Originally Posted by RWA
But as to your question, it remains by no means certain that the climb was caused by pilot inputs. Please refer to Page 111 of the BEA's third report:-

http://www.bea.aero/docspa/2009/f-cp...90601e3.en.pdf

This shows that, at the time the THS started moving and the sudden climb commenced, the PF was applying relatively small movements, up or down - largely consistent, in my less-than-expert view, with an attempt to 'fly pitch and power.' However, the THS was already well on its way to 'full up.'
Huh?



The pitch up coincides pretty precisely with the NU inputs. Airbus pilots please correct me, but I'd guess inputs using 50% of the total stick travel probably are not what you would call "relatively small movements"? The THS is still more or less stationary at this point.
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Old 18th Aug 2011, 16:23
  #3038 (permalink)  
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ventus45;
Originally Posted by ventus45 in post #3028
Then there is the advanced version of the above, the revered "pitch and power". As some have noted, (PJ2 in particular) works OK on climb out, but has wharts on at anywhere near ceiling, aerodynamic, or propulsive.

My point is, all of these "simplistic SOP's" can "lead you up the garden path" and are thus counter productive, and dangerous.

Thinking that maintaining a positive pitch attitude (pick a number, 2, 2.5, 3, 5, degrees - whatever) should be part of a procedure to recover from a stall is idiotic. Thinking that the use of power is a primary or even a seconday way to recover from a stall is idiotic.
I think you're confusing the published response to the UAS with a previously-published stall recovery procedure. Please read my post carefully. I'm not discussing the stall or stall recovery. I am discussing the UAS Memory drill in force at the time of the accident, and also discussing the crew's response to the loss of airspeed information.

It is the UAS procedure to which I refer when I state that maintaining level flight with pitch-and-power settings existing just prior to the event will keep the aircraft in stable, level flight, (obviously the crew has to fly the airplane to do this...), until the pitots and the affected ADRs sorted themselves out.

The crew had all information necessary to maintain level flight, (altitude, VSI, N1, etc), to do this but instead instantly pitched the aircraft up and essentially maintained that pitch up until the aircraft ran out of energy and stalled. That would have been the time to reduce power to idle and pitch the nose down.

Whether recovery from the stall, which had become firmly established with the NU SS inputs after the apogee, was possible or not remains an open question for aeronauticists but the prevailing opinion is, notwithstanding the potential to aerodynamically stall the horizontal stabilizer due to a full-down elevator and without rolling the THS -13 position forward even just a little, that if such recovery had begun around FL350 on the way down, that it was possible. I have read and heard that it is a testimony to the design of the aircraft that the elevator retained some effectiveness right up to impact. Some will disagree with the possibility of recovery or offer other scenarios, lower or higher, but the point is essentially moot after the apogee given the sidestick inputs.

FYI, Boeing and Airbus have already discussed responses to the stall with a view to indicated changes. Airbus presented the changed procedures at the 17th Performance and Operations Conference in Dubai and the pdf can be found here.
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Old 18th Aug 2011, 16:40
  #3039 (permalink)  
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BOAC;
PJ2 - whatever you think of the "5 deg nose-up" it would not have killed all. The a/c would have flown reasonably happily while the UAS drill was actioned. Any stall warning that might have been thus induced could have been actioned as normal.
Respectfully, I disagree.

First, it is clear that maintaining a pitch attitude of exactly 5deg can be problematic and I think that's what happened here - the PF did not have the experience at high altitude flight to achieve precise control and over-pitched in the same way as the PIOs were introduced in roll - (the reductions in roll show that he learned quite quickly about the sensitivity of roll direct).

Second, the moment one begins the climb one reduces predictability and stability at precisely the moment when both are required to retain some situational awareness and assured energy level of the aircraft. Level flight is most certainly more predictable and any pitch attitude required by rote when the circumstances do not warrant it means something is wrong either with the drill itself or the way it is being interpreted and actioned. In my view, both phenomenon are occurring here in various quarters.

By pitching up to "more or less 5deg", with thrust in CLB and A/THR likely disconnected either by the aircraft or as per the UAS drill and in "THR LK" many unknowns are introduced the most critical one being the energy level (speed) of the aircraft while transitioning from level flight to the climb resulting from the increase in pitch with the possibility of a decreasing speed due to a slightly higher than 5deg pitch.

The airplane was stable before, so why momentarily destabilize it by climbing which is what 5deg NU is certainly going to do? Maintaining level flight prevents the introduction of these unknowns and permits a calm cockpit while reaching for the QRH.

In fact, by the time the QRH page is found and the numbers read out, the UAS event would have been over and normal indications would have returned on this flight. As someone said, this should have been a log-book entry.

Last edited by PJ2; 27th Aug 2011 at 05:41.
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Old 18th Aug 2011, 16:49
  #3040 (permalink)  
 
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Originally Posted by PJ2 View Post
FYI, Boeing and Airbus have already discussed responses to the stall with a view to indicated changes. Airbus presented the changed procedures at the 17th Performance and Operations Conference in Dubai and the pdf can be found here.
Thanks, PJ2!
Sadly, it's just a pdf of a PowerPoint slideshow.... one can still hope for the full text of the presentation at the conference.

That pdf almost reads as if the authors had been reading PPRuNe
But, then: pilots, and designers, and engineers, and investigators, even if they don't post here, are not as stupid as some posters here try to make them out to be.
That they arrived at the same or closely similar conclusions as the more reasonable posters here, is barely astonishing.
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