AF 447 Thread No. 9

[Rockhound]

The rough ride - be it due to weather, stall, whatever - was sufficiently intense to alarm the cabin crew, who called the flight deck on several occasions, at 2:10:55.9, 2:10:59.4, 2:11:02.3, and 2:11:24.9, each time without receiving a response.

[Lonewolf_50]

Lyman:

5. Loss of dedicated cooling to the avionics. A lot of stacks of heat producing equipment. If I was a smartie, I might exhaust the heated cooling air from the avionics bay into the cockpit environment? Might that explain the smell?
Lyman, have you taken a look at where the avionics are located in an A330? I refer to the heat producing items.

Might be easy to check, it could be entirely off base... If a fan motor went tu, could it produce the noise referenced by BEA as "increased cockpit noise" (unidentified)?
A fan motor might, but which one are you referring to? A vent fan?

Long ago, I reminded myself that a return up the aisle to his (Captain Dubois) office would be seriously "uphill"... Quite a climb actually...About four times as steep as he may have "expected". He walked into three seconds of STALL WARN, so combined with the uphill climb and the chirp of STALL: "hey knucklehead, get the nose down, you looking for a swim

Lyman, even with an uphill walk, Captain Dubois did not have an altimeter at his rest seat. He has no way to know the altitude and airspeed of the aircraft until he enters the cockpit, even though I think by this time the engines have been at TOGA (and perhaps back to idle before he returns? don't have the time line in front of me) so his aural cues might be a red herring as he heads up toward the cockpit to find out why Robert has summoned him.

He enters, and may or may not see an airspeed that makes sense to him. I am not sure if speed indications were valid or not at that point. If they were, and he's already stalled, they'd not be at values that would make any sense to a man who left the cockpit at Mach 0.82 in straight and level flight. He's got to play catch up immediately. Sadly the man who summons him is not recorded as providing a concise situation brief of "our story so far" in the cockpit.

I get the idea that Captain Dubois enters, and looks at various instruments.
He sees an airspeed value that makes no sense.
He then look at the back up instruments that are more or less in the center of the display area, and again sees an airspeed value that makes no immediate sense. (Perhaps this explains his "this is not possible" remark).

His pilot in the Right Hand Seat, Bonin, is explaining that he hasn't got control of the aircraft, that his speeds are all wrong, but I never get the impression that he gets across to Captain Dubois just what is wrong. (Since he doesn't seem to know that he's stalled, that is no surprise ...)

Dubois has to establish an instrument scan (while not sitting in his usual seat, and with airspeed indications that may or may not be reliable, and most likely are values that he finds strange) and talk the flying pilot back into flying the aircraft. (See my points to jc up there a few). He has to, since Bonin is obviously having trouble with that.

While Captain Dubois' instincts seem to be right, his situational awareness isn't matched with his situation. (I may be hanging on the "not possible" thing far too thoroughly here). He has to piece together what his airspeed, Rate of Descent, and Altitude inputs mean all while being told that there is something wrong with the aircraft by the guy at the controls.

In other words, I belive he has no idea if the crew had descended and was climbing back up as he walks to the cockpit, or if the rumbling and turb he feels is from ITCZ weather, other turbulence, or what, but I don't think his brain is associating "buffet and turbulence" with "stall." At least not initially.

He has a lot to soak up and may not actually have been utterly focused on the walk up, other than thinking
"What's wrong that Robert has called me?"
and only really gets the brain in gear as he look at the displays and has to overcome the

WTF??? :confused:

reflex.

I work under the assumption that Captain Dubois had no idea that things were AFU as he walked up the aisle to the cockpit. He had left the aircraft straight and level. He MAY have assumed that he was being called forward due to increase in turbulence. (Buffet mistaken as turbulence by a pilot who'd not been in an actual A330 stall buffet, eh?) (See notes about cabin crew reports to the cockpit).

That's my take on it, and I may be waaaaaaaaaaay out to lunch.

[gums]

@ RGB....

The discussion of buffet and other sensory inputs while flying a plane is very germane to this group, many who are flying to this day.

Despite all the "protections", "limits", pushers/shakers, audio warnings, etc., there is no substitute for "feeling the plane". Doze will take exception and defend the 'bus system and others, while disregarding basic airmanship and "touch" ( just poking a barb at you, Doze). I gotta tellya that if you feel something you have not felt on your thousands of hours monitoring the AP or flight director or....., that you have failed to consider the plane is not acting as it should given your control inputs or those of Otto or the cosmic FBW control laws or...

The high-speed indications for sub-sonic designs usually involve a high frequency "buzz" or vibration. You may also have aileron reversal, but this is hidden when piloting a FBW system because the system is trying to compensate and you are not directly controlling surface position, but only commanding a roll rate or pitch rate or gee. And as Doze has pointed out, we have not had direct feedback to the yoke/stick since the early 1950's for most planes using hydraulic control systems.

The high AoA/pre-stall buffet is at a much lower frequency than high-speed buzz, like 20 hz or lower. It's a "shake". Ask Retired, as his jet had a super shake, rattle and roll when getting to the edge of the envelope. The later Double Uglies had slats and much reduced buffet, but it was still there. We also had uncommanded roll when the jet was at its limits, and use of aileron was not advised due to adverse yaw and other aerodynamic phenomena. The standard procedure was to lock the stick between your knees and use rudder for roll. this technique works for the old fighters and even Cessna 150's.

The point of our discussion has to do with airmanship and knowing your plane, and it's limits/characteristics. This aspect of our discussion for two years is extremely germane to the incident and will hopefully be emphasized in training and qualification of the crews and the jet.

[rgbrock1]

I think this part of BEA's final report could explain why both PNF and PF did not recognize approach to stall nor the stall itself, no?

"However, positive longitudinal static stability on an aeroplane can be useful since it allows the pilot to have a sensory return (via the position of the stick) on the situation of his aeroplane in terms of speed in relation to its point of equilibrium (trim) at
constant thrust. Specifically, the approach to stall on a classic aeroplane is always associated with a more or less pronounced nose-up input. This is not the case on the A330 in alternate law. The specific consequence is that in this control law the
aeroplane, placed in a configuration where the thrust is not sufficient to maintain speed on the flight path, would end up by stalling without any inputs on the sidestick.
It appears that this absence of positive static stability could have contributed to the PF not identifying the approach to stall."

Gums:

Thank you for the explanation. The only 'buzz' I ever experienced in an aircraft was on a C-130 as the rear ramp was lowered so we airborne grunts could prepare ourselves for jumping out of it!!!

[EMIT]

Lyman,

Even in a Boeing, if an equipment cooling fan quits, a message such as "AFT EQPMT FAN" is generated. The backup fan would immediately take over.
The electronics bay is not really like a boiler room on a Titanic type steamer, not so dramatically hot to flush the flightdeck with a heat wave.
The BEA report has exhausted all sorts of messages from the system, and the ONLY failure that occurred was a temporary loss of accurate pitot pressures.

Change of background noise - well, open or close one of your personal vent holes for instance (no pun intended, just the little blast ports for individual convenience).

The long walk of the captain up the aisle - I believe the Air France pilot rest area is immediately behind the cockpit, where the (passenger cabin) aisle has not yet started.

[jcjeant]

Maybe this can explain why the PNF was frantically calling the captain ....

Extrait du manuel A330/340 d’AF en vigueur à la date du crash :

4.1. MANOEUVRE D’URGENCE

Elle est systématiquement effectuée de mémoire selon une répartition des tâches spécifique. Face à une situation qui nécessite de la part de l’équipage une réaction immédiate, le contrôle mutuel devient secondaire sauf dans le cas d’un pompage réacteur qui conduit à une réduction de poussée. C’est toujours le CDB qu’il soit PF ou PNF qui appelle la réalisation d’une manoeuvre d’urgence en annonçant son titre : exemple : “WINDSHEAR TOGA”.

Extract from manual AF A330/340 in force at the time of the crash:

4.1. EMERGENCY OPERATION

It is systematically carried out according to a memory allocation of specific tasks. Faced with a situation that requires on the part of the crew an immediate response, mutual control is secondary except in the case of a pumping engine which leads to a reduction of thrust. It is always the captain it is PF or PNF called the realization of an emergency maneuver by announcing its title: Example: "Windshear TOGA".

[Clandestino]

HazelNuts39, thank you for correcting me. I was under impression that 1G shake is far too excessive, yet it seems that's just what AF447 went prior to stall. I don't think such a heavy vibration can be ignored, seems that crew either totally freaked out and was unable to understand what was the source of it or somehow believed they have strayed into Cb and it was turbulence.

IMHO, magenta line on real fig 64 (report in French) makes one of the most depressing reads in the report.

Time 0hr.09min FL. 34.992 Static temperature (°C) -43.5
Time 2hr.10 FL 35.044 SAT -38.8
(...)
The TAT has warmed from -42°C to -38.8°C over a very short time.That "very short time" was two hours.
The PF was task saturated. Saturation was self inflicted. Had he recognized sudden drop in speed for what it was and called out UAS, we wouldn't be discussing the AF447 case any more than we did all the other loss of airspeed indication on TA Airbi. Damn it, if he only got shocked into paralysis, he would be better of.

Training issue, and possibly an Airbus and Air France Indoctrination Issue. Education and training go hand in hand with indoctrination. Possibly. Maybe it goes even deeper, down to flight schools and "Principles of flight" lessons.

For those that have not flown a FBW system Thank you for explaining the way FBW works on F-16. FBW is just generic term and different FBWs can be set up in radically different manner. Compared to Viper's, Airbus' is "same, same but different". It has no G-trim, it is flightpath stable. So no need to trim it in climb or pull in turns. Stick free, it follows the flightpath.

And now, Airbus shows us that the jet DOES HAVE a point on the pitch coefficient curve that is "neutral".Well... no. Aerodynamically it is stable yet with FBW intervention in ALT2 law, where low and high speed stability are lost (as is expected when there is no reliable speed measurement), it does not become neutral but unstable.

Personally, a buffet of 0.1 gee Nz seems adequate to provide a warning without any fancy chimes/clangs/etc. And a buffet much higher than that once in the stall should have been a very big indication of what the jet was doing.
Actually, I was mistaken. It was ten times as much.

The high-speed indications for sub-sonic designs usually involve a high frequency "buzz" or vibration.Herein lies the problem; wings design advances much faster than textbooks are updated. Boeing 757, entering service in 1983 needs mach trim. Airbus 320, entering service in 1988 needs it not. Airbus 330, entering service in 1994 does not suffer from mach buffet at all and has so steep drag rise past Mmd it is very hard to overspeed her. While AoAcrit is always affected by mach no, the effect is much more pronounced on 330 than on 320. Yet, all the time there are many airmen still learning from the books of yesteryear, unable to tell which chapters still apply and which not so they keep on seriously discussing about pitch-up of swept wings when stalled, aileron reversals, coffin corners... almost as if MiG-17 is the current state of the art.

I think this part of BEA's final report could explain why both PNF and PF did not recognize approach to stall nor the stall itself, no?No. It would have been an issue, if the crew pulled up, let go of the stick(s) and aeroplane pulled and trimmed into stall by itself, FBW fighting to maintain the flightpath as the airflow over the wings got detached. There is no way to check for positive static stability without controls at neutral and right stick was largely nose-up.

[Ian W]

Lonewolf50
Well, that's why those folks in suits are paid.

I have a few ed thoughts on what I think of MBA's who aren't pilots running airlines ... but that does not belong in this thread.

AF447 has to me shown that Air France (and perhaps a good portion of the industry?) does not make the points I allude to above a priority. (I may be overstating this, or may simply be wrong.) Maybe the idea I have would be that they have a system in place that doesn't achieve that end even if that were its intention.

Result: a crew unable to fly and CRM its way through a malfunction, with fatal results. From the CVR excerpts released, I get the impression of a crew that were trying and trying to get the situation under control, but they were trying the wrong things to resolve their malfunction. (And one could argue that the "how" of their trying, as a crew, was not what we have come to expect).


I have known some of the :mad: 'suits' that you refer to. I am willing to bet that some of them will have calculated that there is no cost benefit in more pilot training in manual handling at cruise level unless there are more than 1 crash per [name a period of time - say 8 years]. This doesn't match with the professed our first priority is safety - but they are 'behind the curtain' of the organization.

[gums]

I shall take on Cland here, not as much for honor, but for experience and no small amount of aero knowledge for a "dumb fighter pilot".

To wit:

Airbus' is "same, same but different". It has no G-trim, it is flightpath stable. So no need to trim it in climb or pull in turns. Stick free, it follows the flightpath.

The normal law and the alternate laws are not "attitude" biased as one would expect in the old days of the autopilot "attitude hold" mode. The thing is programmed to hold a gee! In Normal, the pitch attitude is taken into account, so it does not try to hold one perfect gee if in a climb or descent, but whatever gee is required for the pitch attitude. So in some sense, it has an attitude function built in. Once outta Normal, it appears to be strictly a gee command with pitch rates blended. AoA seems absent to any large degree.

Make no mistake. I do not advocate the same control laws we had in the first operational FBW jet ever flown ( can't resist the plug, heh heh). A trimmed gee is not a good thing for the heavy transports, IMHO. More AoA bias seems better, but what the hell do I know.

Yet, all the time there are many airmen still learning from the books of yesteryear, unable to tell which chapters still apply and which not so they keep on seriously discussing about pitch-up of swept wings when stalled, aileron reversals, coffin corners... almost as if MiG-17 is the current state of the art.


Good observation, Cland.

About the Mig-17..... Some of my friends had the chance to fly the sucker, and it behaved exactly as expected ( there's a place in Nevada that has "funny" airplanes). Some controls had direct linkages to the surfaces ( augmented on a few), but it was honest and let you know when getting close to trouble. Funniest thing was the back stick pressure above about 4 gees - feet on dashboard and both hands pulling back, heh heh). You can ask some of my friends that encountered it in 'nam and they will tell you about how good it was in a manuevering fight, and in last year or two they took advantage of its bad characteristics.

Well... no. Aerodynamically it is stable yet with FBW intervention in ALT2 law, where low and high speed stability are lost (as is expected when there is no reliable speed measurement), it does not become neutral but unstable.

Wrong. Aero is aero, and the FBW system can only do so much. I do not believe that the jet becomes unstable, only that there is an AoA and cee gee combo that enables it to reach a stable, stalled condition that we did not realize was possible.

All the data I have seen shows that the 'bus does not have an AoA/cee gee combination that makes the jet unstable. The intervention by FBW laws, limits, protections can only do so much. In my case, we were actually unstable until about 0.95M. So HAL took care of us, but enabled fabulous pitch rates, sustained turn rates, sustained gee and such that had never been seen.

For all:

I joined this fray to provide some perspective of FBW evolution and its good things and insidious bad things.

I respect the pilots here and hope to meet a few one time for a few beers before I pass on.

[Lyman]

EMIT.. Thanks for the scoop. I am lookin at a schematic of the a300 E bay, and see transformer rectifiers, aC generator controls, etc. the bay is directly behind the cockpit area, and below it. I see possibilities of heat source, and so for now, I won't abandon the idea, just put Er on hold.

LoneWolf... By uphill, I mean a 15 percent grade, steeper than the steepest legal road in the US, by five percent. Yes rest is just behind and starboard of the cockpit, and when he rolled out, it would not have been airspeed he'd consider, but deck angle. At 350, a deck angle of 13,14 degrees would startle a passenger, not to mention a Captain duBord....he walks in on the crew, sees low speeds, leans against the back of jump seat to catch the angle, hears the stall SV And cricket, and says "hey, you, drop the bleep nose..."

Re BEA. One of the criticisms I have of this D- report is that too many data points are presented without explanation, not even an "unk". EG "there is a noise in the cockpit". You don't say... One is left to ponder the wisdom of leaving data in that serves only to accomplish...nothing?

They could easily include the acoustic traces of the voices, so we could see the sequence, volume, and location of the vocals....traces would not give away any meaning, but would quantify if not qualify the CVR. As it sits, there is no CVR.

Only meager transcriptions of words, no audio. So it occurs to me the BEA rejects its legal requirement to provide a report to the public. Something so heavily censored and "managed" misses the mission mark.

[CONF iture]

I work under the assumption that Captain Dubois had no idea that things were AFU as he walked up the aisle to the cockpit. He had left the aircraft straight and level. He MAY have assumed that he was being called forward due to increase in turbulence. (Buffet mistaken as turbulence by a pilot who'd not been in an actual A330 stall buffet, eh?) (See notes about cabin crew reports to the cockpit).
Captain Dubois has been hearing the continuous STALL warning since he was behind the locked door. How long did he spend behind the door waiting for someone to unlock it, we don't know, no mention of the cockpit call on the CVR ... ?
When finally he got in, the continuous STALL warning has ceased. For him the STALL is something from the past ... what's going on now that is not a stall ?

[Machinbird]

The rough ride - be it due to weather, stall, whatever - was sufficiently intense to alarm the cabin crew, who called the flight deck on several occasions, at 2:10:55.9, 2:10:59.4, 2:11:02.3, and 2:11:24.9, each time without receiving a response.
Rockhound, I noted these attempts at communications also. You are the first on this forum to have mentioned it that I have noted (but I'm presently skip-reading this thread).

This was during the initial period of heavy buffet and wing drops (not roll oscillation). It would appear there was a level of consternation among at least some of the Cabin crew.

I also wonder if there might not have been a tell tale vortex off part of the aircraft that indicated a very high AOA. Maybe the first to know they were stalled were the ones in back :ooh:, but we will never know.

[Lyman]

Does the tailplane have buffet in Stall? Also, the airstream noise at the aft must have been very odd, and loud...the noise coming off the TE of the wings must have quite a shriek...I think lead FA was 'Mary Ann" a shame no one will know what she had to say. Probably "Not relevant to the flight". Must be quite a blow to the family, "not relevant"...

[gums]

Good grief, Lyman.

Nobody that could do anything was in the rear of the jet.

The tail surfaces were probably in "clean air" due to the attitude of the jet, and had the pitch authority to get nose down attitude if only the pilot(s) tried. So I can't see any burble or buffet from the tail. AF and BEA admit that there's a "neutral" zone on the pitch coefficient curve that results in a constant pitch attitude with no inputs by the pilot. The jet still has a positive static stability, so pushing forward to overcome the control law that keeps trying to achieve one gee would eventually result in a downward vector. Let's face it. The crew did not realize that they were in a stall and may have been relying on the urban legend that "you can't stall this jet".

I can just see Appendix "Z", section "x" of the report. Before being crushed by impact forces, passenger 'X' cried out on his iPhone that unusual forces/vibrations were present due to tail surfaces in a fully stalled jet. BEAM ME UP!

[Lyman]

I wasn't thinking the crew in back had any input at all, probably wanted to know what was going on, and then why their first comm was not acknowledged. I was thinking there were other crew besides the pilots, that's all...

[EMIT]

What she said is duly noted in the CVR transcription
(at times as noted by previous posters)

allo?

oui

allo?

Then no word, but a sound similar to one putting the phone back in the cradle

(word or group of words with no relevance to the conduct of the flight)?

Then no words but a sound similar to the ending of the cabin interphone communication

Needless to say that the pilots were to busy to pick up the phone.

[john_tullamarine]

Ref post 506 (http://www.pprune.org/tech-log/489774-af-447-thread-no-9-a-26.html#post7301659) ..

The jet still has a positive static stability, so pushing forward to overcome the control law that keeps trying to achieve one gee would eventually result in a downward vector

This may have been one of the problems confusing PF. Static stability (which is nice to have as it feels right) is to do with stick forces rather than deflection. The basic requirement is that the pilot has to exert a pull force to maintain speed below the trim speed .. ie, release the stick and the nose wants to pitch down.

The description given is akin to neutral or negative static stability which would be quite distressing to most pilots without test experience and much more so to one with limited hands on stick and rudder experience overall, compounded by a life of watching and button pressing ..

[mm43]

compounded by a life of watching and button pressing .. Couldn't do much except ...:ok:

[BWV 988]

RetiredF4
When pitch is established (lets sáy 10°) and the aircraft is decelerating, the body would feel a descending sensation even if still climbing.

But wouldn't the Captain have noticed the sustained, unusual attitude? As the person ultimately in charge of the flight, going through the ITCZ with two youngsters up front, he could be expected to pay a bit of attention. The PNF must have thought it possible to get to the flight deck, or he wouldn't have been so annoyed they were on their own.

Rockhound
The rough ride - be it due to weather, stall, whatever - was sufficiently intense to alarm the cabin crew, who called the flight deck on several occasions, at 2:10:55.9, 2:10:59.4, 2:11:02.3, and 2:11:24.9, each time without receiving a response.

It appears the crew was more concerned than the Captain.

[Clandestino]

I shall take on Cland here, not as much for honor, but for experience and no small amount of aero knowledge for a "dumb fighter pilot".

Hey, I never called you dumb... or for a moment thought you were. Actually, I find your contribution to thread very valuable.

The thing is programmed to hold a gee! We had this discussion before; maintaining one local gee when straight and level is consequence of chasing the stable flightpath, not the principle on which system is based. For pilot, difference is most of the time negligible.

I do not believe that the jet becomes unstable, only that there is an AoA and cee gee combo that enables it to reach a stable, stalled condition that we did not realize was possible.Sorry, I have mistakenly believed you have referred to the part of the final report pointed out by Retired F4 and rgbrock1; that FBW makes the Airbus behaviour slightly unstable by maintaining the flightpath with the speed changes while you were talking about post-stall stability. Flying at such a high AoA was outside the certification scope, as it is assumed that pilots will recognize the stall promptly and initiate the correct recovery action so no one has ever tried to reach extreme AoA in test flight. However, from DFDR data it can be seen that aerodynamics were not enough to keep AF447 stalled; at about 2:11:45, THS is winding up and is 2-3 degrees shy of full nose up, elevators are fully nose up, as trust levers get retarded N1 goes down and nose drops from +15° to -10°.

[rudderrudderrat]

@ Clandestino,

Post #477
"From the CVR report:
02.06.54 the crew say "Minus forty-two we won’t use the anti ice that’s a plus."

There are very few TAT recordings reported.
However, please see the report published in July11, page 86.
Time 0hr.09min FL. 349.92 Static temperature (°C) -43.5
Time 2hr.10 FL 350.44 SAT -38.8"
by Clandestino
Originally Posted by rudderrudderrat
Time 0hr.09min FL. 34.992 Static temperature (°C) -43.5
Time 2hr.10 FL 35.044 SAT -38.8
(...)
The SAT has warmed from -42°C to -38.8°C over a very short time.
That "very short time" was two hours.
@ 02.06.54 the crew observe the SAT as -42°C
@ 02.10.00 (Interim report July11 page 86) SAT -38.8
By my maths, I make that 3 minutes and 6 seconds,
How do you make it two hours?

Edit.
However, from DFDR data it can be seen that aerodynamics were not enough to keep AF447 stalled; at about 2:11:45, THS is winding up and is 2-3 degrees shy of full nose up, elevators are fully nose up, as trust levers get retarded N1 goes down and nose drops from +15° to -10°.

The aircraft had 45° angle of attack.
Even if the nose was lowered by 25° I still make that 20° angle of attack.
Do you still think that that "aerodynamics were not enough to keep AF447 stalled"?

[slats11]

@ 02.06.54 the crew observe the SAT as -42°C
@ 02.10.00 (Interim report July11 page 86) SAT -38.8

Thanks for these times Rudder. So using these data points, TAT was increasing at the rate of 1 degree per minute. Similar to the rate of increase with routine descent. You would expect the climate control to cope with this without the cockpit becoming uncomfortably warm.

So why did PF note at 2.08.47 that "You can feel already that it’s a lot hotter"

And why did PNF agree at 2.09.20 that "It’s amazing how hot it is all of a sudden"

It certainly doesn't sound normal or routine.

In fact, the increased temp is pretty much the last thing that PF and PNF ever agreed on.

[mm43]

In fact, the increased temp is pretty much the last thing that PF and PNF ever agreed on. I agree with you on their comments, but when viewing the FDR printout it is difficult to detect the change as the graphics have insufficient resolution. One possibility is not so much the temperature, but a sharp rise in the relative humidity which would have created the same feeling.

[philip2412]

captain.
Ithink that pnf was hesitating to take over brcause he was not assigned pilot flying.and it feels like there had been personal issues that bonin was pf.Maybe we should no more about the personality of the captain.pnf had quite a lot experience,so why was he so eager that the captain comes back,instead of taking command and doing the right thing.

[AlphaZuluRomeo]

Hi gums,

The normal law and the alternate laws are not "attitude" biased as one would expect in the old days of the autopilot "attitude hold" mode. The thing is programmed to hold a gee! In Normal, the pitch attitude is taken into account, so it does not try to hold one perfect gee if in a climb or descent, but whatever gee is required for the pitch attitude. So in some sense, it has an attitude function built in. Once outta Normal, it appears to be strictly a gee command with pitch rates blended. AoA seems absent to any large degree.
Would you be so kind as to elaborate on the bolded sentences? Source and so on?

Why do I ask? Two things:
- AFAIK, stick free the aircraft holds its path, not "1 g". It may be that the path gives 1g (often it is!) but the law is "g demand" (i.e. stick not free) not "g holding".
- I was unable to find any credible document indicating that the stick free longitudinal behavior is different in Alternate law versus Normal law.

Thanks in advance :)


Hi rudderrudderrat,
However, from DFDR data it can be seen that aerodynamics were not enough to keep AF447 stalled; at about 2:11:45, THS is winding up and is 2-3 degrees shy of full nose up, elevators are fully nose up, as trust levers get retarded N1 goes down and nose drops from +15° to -10°. The aircraft had 45° angle of attack.
Even if the nose was lowered by 25° I still make that 20° angle of attack.
Do you still think that that "aerodynamics were not enough to keep AF447 stalled"?
The aerodynamics alone: you don't know. What you may notice is that the THS & elevators, commanding nose up, might have slightly influenced clean aerodynamics at that point.
What you don't know is what AoA will have been reached with thrust idle + stick full nose down and maintained there as long as needed (meaning eventually the elevators and THS would have winded down).
It can't be proven until test flights take place, and we all know there won't be such tests and why. OTOH, all indications so far show the nose would have gone down, down down, and the AoA would have followed.
Therefore I too do think that aerodynamics were not enough to keep AF447 stalled, and that this PoV ('locked in stall') is irrelevant. And it also may be used to used to divert attention BTW (this is not for you, rudderrudderrat, I'm thinking about organisations that have an agenda, out there).

Cheers.

[HazelNuts39]

So why did PF note at 2.08.47 that "You can feel already that it’s a lot hotter"I wonder whether the heat exchangers in the air conditioning packs could be obstructed by ice particles.

[HazelNuts39]

I was unable to find any credible document indicating that the stick free longitudinal behavior is different in Alternate law versus Normal law.FCOM 1.27.30 Reconfiguration control laws: Alt 1/2; Pitch control,
Flight mode:
Flight law is a load factor demand law, similar to normal law, with limited pitch rate feedback and gains, ...
Flare mode:
Flare law is identical to normal flare lawAs I read this, alternate law pitch control is not identical to normal law.

[Lyman]

EMIT:

"What she said is duly noted in the CVR transcription
(at times as noted by previous posters)

allo?

oui

allo?

Then no word, but a sound similar to one putting the phone back in the cradle

(word or group of words with no relevance to the conduct of the flight)?

Then no words but a sound similar to the ending of the cabin interphone communication

Needless to say that the pilots were to busy to pick up the phone."


If the pilots did not pick up their phone, how did she end up on the Cockpit voice recorder?

woodja51

"All the rest is academic , a bunch of folks died due to failure to fly the aircraft " that appears to be the case. However, failure to fly the a/c is a huge topic. Can you include some other evidence?

[woodja51]

Lots of talk about lots of stuff... Facts:

Unreliable airspeed , if aircraft flight Jeopardised , ap at fd off. No more no less

Then

Stall recovery( if you put it there)...


Lower attitude

End of event.

Simple , problem solved no crash no dead people.

All the rest is academic , a bunch of folks died due to failure to fly the aircraft

And transit a temporary anomaly.

I sympathise with the loss of life , but the race to the bottom in flight training must be to blame at the core of this and is due to airline, manufacturers race to the lowest flight training cost base possible to meet min regs only.

It will only get worse with MPL.....but that is the future.

[philip2412]

There`s one fact in this whole scenario,which is for me the most unbelievable part in the crew-captain relation.
we have 2 pilots in todays standard with a lot of experience(doing away for a moment the AF defiences in training we all konw about) flying ong haul for years no city hoppers.they were clueless,desperate,no solutions to solve their problems ,both (?) eagerly awaiting the captains return for relief.
And when that moment arrived the cpt back n cp they both are not able to give a professional briefing,the last opportunity maybe to save their lifes.What di they expect from him ? guessing ?
Can somebody pls explain that ? This can`t be explained by their mental state only.

[Lyman]

I honestly think the actual cause for this accident is at hand. This thread has been three years analyzing incomplete and possibly inaccurate, if not fraudulent data. Stand by.

"There`s one fact in this whole scenario,which is for me the most unbelievable part in the crew-captain relation.
we have 2 pilots in todays standard with a lot of experience(doing away for a moment the AF defiences in training we all konw about) flying ong haul for years no city hoppers.they were clueless,desperate,no solutions to solve their problems ,both (?) eagerly awaiting the captains return for relief.
And when that moment arrived the cpt back n cp they both are not able to give a professional briefing,the last opportunity maybe to save their lifes.What di they expect from him ? guessing ?
Can somebody pls explain that ? This can`t be explained by their mental state only."

More than one fact. For three years this crew has been allowed to seem consummately incompetent, crazy, or impaired. Would it take much to upset the apple cart? Remains to be seen.

[thermalsniffer]

Philip2141

This has always bothered me. When the CVR first came out, some were quick to support PNF as having some concept of the situation but limited by authority and what PF was actually doing.

BUT

PNF is desperate to get the Capt. back to the flight deck and when the Capt. gets there all he offers is:

"What’s happening? I don’t know I don’t know what’s happening"

and

"We lost all control of the aeroplane we don’t understand anything we’ve tried everything"

IMHO, he was not calling the Capt. back due to command issues, which I believe was suggested earlier--he had no idea what was going on?

Also, what had they tried?

Switch to ATT?

[RetiredF4]

Quote: Clandestino
Well... no. Aerodynamically it is stable yet with FBW intervention in ALT2 law, where low and high speed stability are lost (as is expected when there is no reliable speed measurement), it does not become neutral but unstable.

Quote: Gums
Wrong. Aero is aero, and the FBW system can only do so much. I do not believe that the jet becomes unstable, only that there is an AoA and cee gee combo that enables it to reach a stable, stalled condition that we did not realize was possible.

All the data I have seen shows that the 'bus does not have an AoA/cee gee combination that makes the jet unstable. The intervention by FBW laws, limits, protections can only do so much. In my case, we were actually unstable until about 0.95M. So HAL took care of us, but enabled fabulous pitch rates, sustained turn rates, sustained gee and such that had never been seen.


Well, i´m not sure what you both are getting there, therefore i try to summarize the issue about stability in my own understanding (feel free to correct).

The airframe itself is, no, must be natural positive stable, otherwise it would not be flyable in direct law.

In Nz-Law, which applies in all Laws except Direct Law Ground Law and Flare Law (did i forget one?) the flight control system creates an artificial neutral stability by use of elevators and THS trim, leading to a stable flightpath without SS input. Not the SS drives the elevators, but the flight control system using present flightpath and the demanded change from that flightpath.

Protections are there to keep this flight path stable airframe within the flight envelope, in simple terms to deviate from this ordered stable flightpath when set parameters are exceeded. There are other tasks to be fullfilled by those protections as well, but not of relevance what i try to get at.

When those protections are degraded or lost, we still have an airframe with artificial neutral stability, as the flightcontrol system still works along the demands of Nz Law, but the protections to keep the aircraft within the flight envelope are gone and have to be replaced by the skill of the crew.

In the case discussed here once on the way up to the apogee the Flight Control System was trying to maintain the flightpath with elevator deflection and THS trim blind to the fact (protections lost) that it would run out of airspeed in doing so, will finally stall, as it did. The crew, who should have compensated for those lost protections was most probably unaware of that fact too, otherwise they wouldn´t have continued to apply NU SS. This NU SS had not much influence after the stall happened, as the flight control system was beyond it´s capability to maintain the flightpath (descending already instead of continueing on the ordered climbing trajectory). The SS movement between NU and Level had no effect and showed no reaction to the aircrew, thus it might have contributed to the confusion.
Neutral SS wouldn´t have cured the problem, only ND SS would have changed the trajectory.

What BEA was getting at with the cited paragraph few posts before is imho, to show the reason for this behaviour without getting too much into details.

@ gums my friend in arms, if i remeber correct the F16 airframe was naturally unstable and a diferent beast. Your comment to blend the Nz-Law with the present (and available) AOA value for a backup in ALT laws with normal protections lost seems a reasonable consideration.

[HazelNuts39]

If the pilots did not pick up their phone, how did she end up on the Cockpit voice recorder?
2:10:53,5 A first cabin crew or flight rest facility call (high-low chime) was heard
2:10:55 A noise on track 1 of the CVR, which may be the impact of the microphone striking a panel
2:10:55,9 Track 1: allo?
2:10:59,4 oui
2:11:02,3 allo?
2:11:08,3 noise of someone trying to park cabin interphone handset
2:11:09,8 - 2:11:27 Five call signals to the crew rest facility

[AlphaZuluRomeo]

Hi HazelNuts39 :)

FCOM 1.27.30 Reconfiguration control laws: As I read this, alternate law pitch control is not identical to normal law.
Thanks, I maybe should have precised that I've read that too ; "limited pitch rate feedback and gains" apply to a manoeuver, i.e. when the crew commands something via the stick.
My question was about the stick free longitudinal behavior. It remains unanswered.

[jcjeant]

captain.
Ithink that pnf was hesitating to take over brcause he was not assigned pilot flying.and it feels like there had been personal issues that bonin was pf.Maybe we should no more about the personality of the captain.pnf had quite a lot experience,so why was he so eager that the captain comes back,instead of taking command and doing the right thing. Maybe it's because AF culture .......
Extrait du manuel A330/340 d’AF en vigueur à la date du crash :

4.1. MANOEUVRE D’URGENCE

Elle est systématiquement effectuée de mémoire selon une répartition des tâches spécifique. Face à une situation qui nécessite de la part de l’équipage une réaction immédiate, le contrôle mutuel devient secondaire sauf dans le cas d’un pompage réacteur qui conduit à une réduction de poussée. C’est toujours le CDB qu’il soit PF ou PNF qui appelle la réalisation d’une manoeuvre d’urgence en annonçant son titre : exemple : “WINDSHEAR TOGA”.

Extract from manual AF A330/340 in force at the time of the crash:

4.1. EMERGENCY OPERATION

It is systematically carried out according to a memory allocation of specific tasks. Faced with a situation that requires on the part of the crew an immediate response, mutual control is secondary except in the case of a pumping engine which leads to a reduction of thrust. It is always the captain it is PF or PNF called the realization of an emergency maneuver by announcing its title: Example: "Windshear TOGA".

[HazelNuts39]

My question was about the stick free longitudinal behavior. As I understand the C* control law:
C* = q + a*nz, where q = pitch rate, nz = incremental loadfactor, and a determines the 'blend' between nz and q feedback.
For side stick neutral C* = 0, hence q = -a*nz

[Lyman]

Hi HazelNuts...

From EMIT: "Relevant
What she said is duly noted in the CVR transcription
(at times as noted by previous posters)"

What I said: "How can her voice appear on the CVR?" The "allo,Oui,allo" is from Pilot Bonin....

[Lyman]

Thermalsniffer...

I do not mistrust PNF comment, and I believe he is correct: they tried everything to regain the flightpath. Their problem started at autoflight disable, and flight control disable. Pitch control was unavailable, navigation had been lost, and other problems emanating from a problem in the cockpit area were cascading. Neither pilot understood the scope and hopelessness of their issues. After Captain re-entered the cockpit, he immediately understood the crew were doing what they could, but him taking the controls would be not advisable, what control they had might well be lost if a transfer to him was accomplished.

PNF was reluctant to take control, that is why there was no permanent change.

There is no chance they didn't have the experience of STALL, and know exactly what was happening...To this extent: They were in trouble, and they had no control over the aircraft...the stick traces were not Bonin's. They belonged to the aircraft. Robert took the stick back as Captain returned, his input had no effect, as Bonin's controls hadn't either...in the climb, Bonin's confusion is not confusion, the a/c is not responding to his inputs.

Shortly after 447 was lost, another a/c, a 340, also lost Pitch control...

[slats11]

Trying to assess the human factors issues is crucial - not only to build an understanding of what transpired, but also to decrease the risk of a recurrence. Unfortunately this human factors assessment has been made more difficult as we have only been given selected extracts from the CVR. I am sure there are plenty more clues in the bits left out. In addition, we lack the all important quality of the speech - tone, volume, tempo etc

However I do understand and respect the view of BEA that some things do not belong in the public domain. All we can hope is that the human factors people that were involved in the investigation and privy to all the detail learned all there was to be learned.

Why did the Captain take more than a minute to get back to the cockpit? He was a 58 year old male. He had been in the cockpit for 4-5 hours prior to his rest. He would have had a meal and maybe some coffee. Where would he most likely go immediately after leaving the deck and before resting? I would guess that he was in the bathroom?

Despite all the talk here about the kids in the cockpit, both PF and PNF were reasonably experienced. The Captain seemed happy to leave for his rest, despite commenting that it would be turbulent during his rest.
1 h 51 min 58 It’s going to be turbulent when I go for my rest.

There was a very short handover to PNF when he arrived. Less than a minute between his arrival and Captain's departure. Despite ICTZ. Despite turbulence. Despite rising temp and a discussion only 10 minutes earlier about implications on max altitude.

So he seemed pretty confident in the other two pilots. Maybe too confident?

The guys really let Dubois down with their gibberish when he returned. If he was that confident in them and if they were essentially incoherent when he returned, then he may have been immediately overwhelmed by a perception that something very complicated must have taken place. He didn't rush in and take corrective action - because the problem was not clear to him, and no one told him what had happened. So he had to try and make sense of a cacophony of alarms, faulty data, error messages, and bewildered pilots who he believed were competent.

You can't expect someone to explain what they don't understand. But you can expect a concise account of what they did know. Look I not a pilot. But in my line of work (critical care medicine) I frequently get asked for urgent assistance when things go wrong. I don't expect solutions - that's my job. But I do expect to be given some useful information about events before I arrived. I understand this is harder for pilots than doctors - aviation emergencies are relatively rare, pilots may have concerns that their actions were somehow responsible for a problem, and they may even have concerns about their safety. Clear thinking and analytic skills go missing in the setting of unexpected stress and anxiety. But even allowing for all this, these guys appear to have dropped the ball - and possibly lost the final opportunity to recover the situation.

A couple of interesting comments from the Captain in the hour prior to his rest period:
0 h 58 min 07
Captain Try maybe to sleep twenty minutes when he comes back or before if you want
PF Yeah ok that’s kind, for the moment I don’t feel like it but if I do feel like it yeah
Is Dubois really saying he was happy for PF to have a doze while Dubois was having his rest period? Surely I am misunderstanding this.

1 h 27 min 56 How badly we see in this aeroplane with this lighting. It’s not a success
Could he have had trouble seeing the displays when he returned and was sitting behind the 2 pilots?

[HazelNuts39]

The "allo,Oui,allo" is from Pilot Bonin.... He was that female voice?

[Owain Glyndwr]

Gents,

If you will allow me to chip in ....

therefore i try to summarize the issue about stability in my own understanding (feel free to correct).
The airframe itself is, no, must be natural positive stable, otherwise it would not be flyable in direct law. Quite so - but when people say that they are usually talking about the short period motion. CG ahead of aerodynamic centre in the classic sense for stability - that qualification says nothing about the long period (phugoid) motion

In Nz-Law, which applies in all Laws except Direct Law Ground Law and Flare Law (did i forget one?) the flight control system creates an artificial neutral stability by use of elevators and THS trim, leading to a stable flightpath without SS input. Not the SS drives the elevators, but the flight control system using present flightpath and the demanded change from that flightpath.C*, by itself, is a system to shape the short period response into a form that pilots will like. When implemented as Airbus do it acts, in the absence of any further pilot input, to maintain the flight path constant as Franzl says.

But if the flight path is constrained, whether that be level flight or an approach path, the natural phugoid is suppressed because you have taken away one of its degrees of freedom. What you are left with (for the 'natural aircraft at least and apart from a stable short period) is a simple subsidence or divergence in airspeed, i.e.it becomes a speed stability issue and one where what matters is how (Thrust - Drag) varies with airspeed with throttles held constant.

Something like the A330 is speed stable for excursions above the (trimmed) cruise speed because you very soon run into drag rise. Below trimmed speed however it becomes a bit more problematical.

When one takes Mach number effects as well as the classical drag 'bucket' into account modern airliners have a drag vs speed curve that looks more like a flat-bottomed 'bathtub' than the classic parabolic shape. Depending on how thrust varies with airspeed (again at constant throttle) the speed stability is just about neutral over a fairly wide range of airspeed. It varies a bit with altitude, being slightly less stable at say FL370 than at FL350.

It is because of this neutral stability on the low speed side that 'buses' use A/T in cruise to sharpen up the aircraft response to disturbances.

Before anyone starts to yell "I told you so - the aircraft is unstable without A/T" just remember that if the aircraft is only slightly speed unstable (as seems to be the case) it will take a very long time for small initial diversions in speed to develop into serious excursions. Typically, from cruise down to Vs1g might take anything from 5 to 10 minutes but the rate of divergence escalates rapidly as one gets near that point and most of the speed divergence will be in the last say 30 secs. Once you get beyond 'stall' the rate of divergence rockets up. Hence the need for prompt recovery action.

It must also be apparent that modest speed instability, by itself, could not explain this accident. To reach the timescale recorded the aircraft divergence would have to have been 'helped' by pilot action - as it was. But once the aircraft was down to speeds at or below Vs1g the aircraft's natural speed instability would have made a significant contribution to the rate at which speed was lost.

When those protections are degraded or lost, we still have an airframe with artificial neutral stability, as the flight control system still works along the demands of Nz Law, but the protections to keep the aircraft within the flight envelope are gone and have to be replaced by the skill of the crew.
Agreed!

This NU SS had not much influence after the stall happened, as the flight control system was beyond it´s capability to maintain the flightpath (descending already instead of continuing on the ordered climbing trajectory). I'm not so sure about this. The flight control system would still have been trying to maintain the flight path, but the flight path it was trying to maintain was that being demanded by the pilot as seen by SS movements - an increased 'g' command. So far as I can see, the continued NU SS and accompanying THS movement would have made things worse for recovery because they trimmed the aircraft into a higher AoA than it would otherwise have achieved.


Neutral SS wouldn´t have cured the problem, only ND SS would have changed the trajectory. Agreed.

[EMIT]

Lyman,

If Bonin was the speaker, then the words "allo? oui allo?" etcetera would have been placed in his column, labeled "Copilote place droite".

As it is, the words appear in the column labeled, among others, "Autres voix".

The mystery of the voice appearing on Track 1 (Piste1) is not so mysterious - if she picks up her phone, she is on the line, i.e. will be recorded.
Compare it to the situation where a pilot pulls his headset cables from the plug and keeps his speaker off - what is received via radio will still be on the recorder track, even though that pilot will not hear it.

Another mystery solved, I hope.

[gums]

I guess we have to define terms, and "flight path" is one term that may be causing us to debate a few things about the control laws and the natural aero characteristics of the 'bus.

A very good explanation of some things, Retired. But I expand...

Courtesy of some of the pilots here, I have a decent set of the manuals. And from what I see, the FBW system is strongly biased for a one gee flight, and not an "attitude hold" mode as we had/have in many jets with autopilots. It also appears to have little AoA bias, but only some "limits" to stay outta the stall regime. Body rates and gains are contributing inputs, as was also the case in my primitive system. The positive longitudinal stability most of us were/are used to is not based on AoA in this system. Let go of the stick and the sucker shoots for one gee corrected for pitch attitude. If that ain't the way the thing works or is supposed to work, please correct me.

I iterate this point because it's exactly the way our primitive system worked. The biggest difference was we could set the desired trimmed gee, and our system wasn't trying for one gee all the time, nor did it correct for pitch attitude. We had zero static stability "feel" for AoA as most of us are/were used to. Only reason the nose went down when relaxing pressure on the stick was to achieve the trimmed gee ( nominally one gee according our trim wheel, which allowed about 3.5 positive and a bit over one gee negative). If we trimmed full back, and let go, the thing would do a beautiful 3.5 gee loop, and the gee would decrease as we hit the AoA limit until we got to one gee or a bit less. AoA would be pegged at 27 degrees. Coming down the back side, and speed building, the thing would get back to the 3.5 gee trim command and finish the loop.

I bring all this to the table to help folks understand the difference between FBW systems and the conventional control systems we flew that were based on a trimmed AoA. Sure, we could build a great FBW system that was strongly biased for AoA, just like the "old days". In fact, our system did that with gear down. We biased the gee command with AoA to give us the same old feeling we had in the days of yore ( no auto throttle in the Viper, unlike the Hornet, so we could trim for an AoA and use throttle for vertical velocity). In a FBW system you can overcome all kindsa nasty aero characteristics until the confusers go to la la land. The 'bus seems to be a very benign, stable platform. So even in "direct law" it can be flown by humans. Ours was not stable until above 0.95 M or so, and if the control surfaces went to neutral due to computer failure, the thing went nose down ( 22 negative gees on one of our first computer shutdowns due to power failure).

We could build a FBW system that only used the electrons to command control surface position, just like the old days except the hydraulics didn't use a valve at the base of the control wheel/yoke/stick. We could even build one that used electrons to power the actuators for each control surface.

But we haven't done that. We use the neat computers to reduce workload and overcome aero characteristics of the platform. So we see a lot of "autopilot" functions embedded in the system. Those are the things that bother me. Those are the things that gradually destroy basic airmanship and understanding how our jet flies.

'nuf philosophy for now.

[Lyman]

Thanks EMIT.

I thought the recording of the voice was after the lack of pick up from cockpit area. Next time I'll try to engage brain before keyboard.... Well, at least I'll try.

:O

[Rockhound]

I have no idea what Lyman has been smoking. His suggestion that the female voice was Bonin's is ludicrous. According to Otelli, the four transmissions in a female voice recorded on the CVR came through on the intercom speaker, were all made by cabin crew, and were all questioning or exclamatory (he transcribes the call at 2:10:59.4 as "Oui?" and the one at 2:11:24.9 as "Stéphanie!").
Even more ridiculous is Lyman's theory that the aircraft was not responding to Bonin's control inputs. It reacted exactly as expected. At 2:11:34.7 (ca. 1.5 min after Bonin had pulled back on the sidestick following A/P disconnect), at around FL360 and TOGA, Bonin announced that he had lost control of the plane and proceeded to pull the stick even further back and to the left and hold it there for 40 seconds.
Equally silly is the suggestion that Dubois, when he re-entered the cockpit, did not want change places with Robert for fear that all control of the aircraft might be lost. They were still at 35,372 ft, surely to God you'd think you'd still have a fighting chance to rescue the situation.
Finally, let's put at rest, once and for all, the impression that all three pilots were experienced veterans of long-haul flying. Bonin definitely was not. Before leaving the FD to take his rest and designate Bonin as PF, Dubois had to assure himself that Bonin possessed an ATPL.

[Lyman]

My suggestion is you consider that without a complete record, posts like my last one cannot be contested without either full and naive faith in the report, or possession of substantiation that is not in the public record.

[CONF iture]

http://i45.servimg.com/u/f45/11/75/17/84/ltop_a14.gif (http://www.servimg.com/image_preview.php?i=152&u=11751784)

Prends WHAT ... ?

[jcjeant]

We can continue for months to discuss technical specific aspects of the Airbus A330 and continue to speculate about what would happen if and if ..
Nevertheless .. all of these discussions will not bring anything more than what is in the BEA report and even if one member of Pprune find the Holy Grail to solve some problems .. the final report will remain as it is .. that is to say engraved in stone
The next episode (for those who are still fortunate to be there ..) will be the trial court
It may be that short of it .. other experts (judicial) have other discoveries to argue ... and maybe some explanations will be sought from BEA and regulators and airline(s)
The debate (such as currently conducted in PPrune) will certainly be very interesting from all point of view .....

[jcjeant]

Prends WHAT ... ? That can be anything ... a indication from a instrument or display (if this is a finger pointing to it) or even a pill to calm nerves ......

[Lyman]

Why is the altitude alerter intermittent? Aren't they at this stage off assigned 350?

[rudderrudderrat]

Hi Lyman,
Why is the altitude alerter intermittent?
It was sounding continuously until impact. It was interrupted by higher priority warnings such as "single chime"; "SV Stall", "cricket" etc.

No one cancelled it, no one commented on it, it's as if no one heard anything.

[mm43]

... it's as if no one heard anything.It was like background music, nice to have, but can be switched off sub-consciously when concentrating on something else.

[Lyman]

I differ in that the artifact is fin C Chord if replaced by higher priority, instrument protocol would choose another word, besides "fin".

Is there no alert that signifies over ride due priority?

[AlphaZuluRomeo]

As I understand the C* control law:
C* = q + a*nz, where q = pitch rate, nz = incremental loadfactor, and a determines the 'blend' between nz and q feedback.
For side stick neutral C* = 0, hence q = -a*nz
OK, thanks. I really should have paid more attention in math classes, back then. :8
Would that make the Alternate law stick free behavior different from that of the Normal law? q limits is different, yes, but?

[HazelNuts39]

Would that make the Alternate law stick free behavior different from that of the Normal law?Again, I may well be completely wrong, but my interpretation of "limited pitch rate feedback" would be that the alternate law value of 'a' is different from normal law.

[mm43]

Originally posted by HN39 ...
As I read this, alternate law pitch control is not identical to normal law.Following from A330 Instructor Support ManualAs a summary with ALTN law:


within the Normal Flight Envelope, the handling characteristics are the same in pitch as with the normal law
outside the Normal Flight Envelope, the pilot must take proper preventive actions to avoid loss of control, or high speed excursions as he would do it on any non protected A/C.

Would seem to make sense, otherwise the A/P would need to function differently in either law, and so would the pilot using the SS.:eek:

[HazelNuts39]

the A/P would need to function differently in either lawI believe I've read somewhere that the different laws only affect the flight control system interpretation of side stick inputs. The autopilot commands are processed outside of the laws. Protections override side stick as well as A/P commands.

[mm43]

I'll see if I can find anything else, though I must admit I have also seen what you referred to.

[RetiredF4]

@ Owain Glyndwr, mm43,HazelNuts39, AlphaZuluRomeo and all

I read the following out of the A330 technical training manual that AF447 had no high speed or low speed stability protection left (as it would have been iN Alt1), but only protection still available being the load factor protection.

ALTERNATE LAW WITH REDUCED PROTECTIONS
In pitch normal laws, all the protections are available.
In case of loss of surface actuation or of inputs, some protections can be lost. The pitch alternate laws with reduced protections are activated in the FCPCs in case of loss of :
- THS actuation (B+Y hydraulic circuit or 3 motors lost, ...) or - 2 Inertial
Reference (IR) (second self detected) or 2 Air Data Reference (ADR) o
- All spoilers or all inboard ailerons or
- Slat position or pedal position or
- One elevator (B+G or Y+G hydraulic circuit lost, ...).
The angle of attack (AOA) protection is lost and replaced by static stability Vc prot. (see Pitch Laws module).
The pitch attitude protection is lost.
The high speed protection (VMO1) is lost and replaced by high speed stability
VMO2. (see Pitch Laws module).
In case of loss of slat or flap position or aircraft weight computation, the static stability is also lost.
If a double IR failure occurs, the second being self detected, specific accelerometers are used to consolidate the load factor information and pitch attitude rate information from last IR.

franzl

ALTERNATE LAW WITHOUT PROTECTION
In this case, the pitch protections are lost except the load factor protection.
This alternate law without protection is activated in the FCPCs after a triple
ADR failure.

[roulishollandais]

did you heard about the "attracteur etrange" (i do not know the name in english): see james gleick CHAOS. unstability has such a point that gums searched and found on.the a330. congratulations to gums, retiredF4 for the stall, and machinbird for the roll
Thanks

[mm43]

HN39 et al;
Characteristics in pitch


When acting on the stick the pilot commands a constant G load maneuver and the aircraft response is G Load / Pitch rate. The pilot order is therefore consistent with the aircraft response “naturally” expected by the pilot, Pitch rate at low speed / Flight Path rate or G at high speed.
Hence STICK FREE, the A/C maintains the flight path even in case of speed changes. Furthermore, STICK FREE in case of Configuration changes, or thrust variations, etc… the pitching moment effects are reduced by the feedbacks in the control law itself and compensated for by precommands. With STICK FREE in turbulence, small deviations do occur on the flight path but with a tendency of the A/C to regain a steady condition.

As a consequence the A/C is a STABLE PLATFORM and AUTOTRIMMED; it needs to be flown with minor corrections from the pilot on the stick, when the A/C deviates from its intended flight path.

[Lonewolf_50]

jc, the court case won't contribute to aviation safety.

It may make a few wallets fatter.

[Rockhound]

Slats,
It is completely incomprehensible why the captain, after he was summoned back to the cockpit by his crew, made no effort to take control. Indeed, for much of the time he seemed to be little more than a rather distracted observer.
Confiture,
We will never know what the captain was referring to when he uttered "prends ça!" Otelli writes that the BEA investigators thought he meant the Flight Path Vector (the "Bird") in the PFD.
Lyman,
So what if the C Chord seemed intermittent. Surely that alarm would be the least of the crew's worries. The way that plane was rocketing up and dropping back down, it's a wonder the C Chord generator didn't burn out.

[Lyman]

Rock hound...

Yes, I would agree, I was curious about any failure in the a/c, not just what the pilots were doing with it. So you know the parameters of c chord burning out. Where can I find them? BEA are derelict in leaving so much information out. The general drill in a report is that data can be incorporated "by reference", leaving the reader to pore over it, after he locates it elsewhere.

Thanks

[jcjeant]

lonewolf_50
jc, the court case won't contribute to aviation safety.I think it may somehow contribute to safety .. simply by excluding some people by sentences ..
People or organizations that contribute to lower safety or not taken into account by their mismanagement
It may make a few wallets fatter. And I hope this will be those of the victims families
And it may also make a few wallets thin .....

Rockhound
We will never know what the captain was referring to when he uttered "prends ça!" Otelli writes that the BEA investigators thought he meant the Flight Path Vector (the "Bird") in the PFD.I read nothing about that in the final report ...
The BEA report of course ... not the useless Otelli one :8

[john_tullamarine]

(Caveat - I have no specific FBW background)

I am a tad confused by some of the recent posts commenting on stability.

If the aircraft, in degraded modes, gets to the stage of having no computer protections, then it would appear to be unflyable for the typical pilot unless statically stable along with a dynamically stable SPO. If statically neutral or marginally unstable, still flyable if one knows what to do .. and then only for a short while until the fatigue levels take over any semblance of finesse.

However, I cannot imagine that it would have been certificated unless it were stable in the worst degraded mode ?

Has anyone any information regarding the matter ? Specifically,

(a) as modes degrade does the aircraft get to the point of having nil computer assistance ?

(b) if so, what are the stability characteristics ?

I am presuming that there is no flight test data relating the the AF447 extent of stalled flight ...

[chrisN]

roulishollandais, "attracteur etrange" = strange attractor in English. More at :

Strange Attractors - Chaos & Fractals (http://www.stsci.edu/~lbradley/seminar/attractors.html)

If you are interested.

Hope that helps.

[gums]

Yeah, JT, a good question.

Wiki has a fair explanation, but one of my original posts has a link to the Viper's design WRT static stability.

Longitudinal static stability - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Longitudinal_static_stability)

Have to look at my website files to get a link for our design.

Found the Code One articles on my website:

http://www.sluf.org/misc_pages/codeone_v1_n2.pdf

http://www.sluf.org/misc_pages/codeone_v1_n3.pdf

The deal with the 'bus is that what we all knew as "normal" was if you let go of the stick the plane would try to achieve the trimmed AoA ( not gee). So the cee gee was well forward of the center of aero pressure. This meant that when cruising along that the elevators were actually creating a force opposite of the main wing to keep the nose up. By moving the cee gee back and having HAL to help, you could have the elevators creating upwards lift and dramatically reduce "trim drag". In short, both the elevator and main wing were generating lift upwards.

From my A330 manuals, the thing never has an extreme aft cee gee as we had, but it does allow it to be further aft than most of the other jets. This helps for range due to reduced trim drag. Because HAL is helping, you don't feel like you are flying on the tip of a needle if you turn the AP off.

The 'bus direct law is one implementation I described. The electrons directly command control surface deflection via the actuators, just like the old days when our yokes/wheels/sticks moved a valve for the hydraulics. Because the plane has positive static stability, it is still flyable by mere mortals.

What bugs me is that the 'bus reversion sequence is not real clear as to the AoA bias on pitch. At first look, you think that you have some degree of AoA limits and actually command AoA. Then you read all the footnotes and find that some data failures do not provide the expected control response related to AoA. So the jet is still trying to achieve a gee, and the AoA can go to 40 degrees, as we now know can happen.

later from this old dinosaur...

[john_tullamarine]

Thanks for that .. I'll review later on today during a coffee break.

I don't have a problem if the box is still helping out sensibly as what is important is what the pilot is presented with in the worst certification degraded mode ...

However, some of the posts appear to be suggesting that the degradation can extend to nil box assistance and a statically unstable aeroplane.. that's my problem at the moment.

Either such

(a) isn't the case

(b) wasn't considered because the estimated MTBF suggested the probability of occurrence was up there with the other very small numbers .. ?

I probably should have bid onto the A320 when I had the opportunity rather than staying on the FLUF.

[OK465]

(a) as modes degrade does the aircraft get to the point of having nil computer assistance ?

Actually, if you go by the anti-bus crowd around here, the modes degrade as you add FC computers. :}

With only one secondary FCC (of possible 5 total FC computers) available to connect SS/rudder inputs to the flight control surfaces you have a 727.

With either no computers, or no electrical power, you have mechanical control, thru hydraulic actuators, of the THS using the trim wheel, and the rudder using the pedals. Though set up to provide control while resetting computers, as others have said, you can actually land the aircraft, if necessary, in this condition. Complete electrical failure, you've got no choice but to land it this way. Challenging and satisfying. :)

It is never divergent around any axis, regardless of the level of computer assistance or lack of.

The wonderful world of FBW.

[gums]

Thanks, Okie, you nailed it.

There might be more dependence upon electrons than you suggest, but the aero characteristics of the 'bus seem really good to this old fart.

I am not anti-bus. I am bitching about all the reversion sequences and such, which seem very confusing to me. I want something to hang my hat on, and if various sensors are FUBAR, and HAL doesn't use them, I still want to know what I am playing with. I also have a problem with the THS still in operation once outta Normal law. Another thread topic.

I joined the fray here to show that some knew about unexpected aero problems over 30 years ago that the cosmic FBW systems could not fathom. It's why I detest the term "protections". Although our system had different mission requirements than the 'bus, it was the first one fielded with a fully FBW system and had several hundred jets flying within two or three years. We initial cadre were afraid that the newbies would forget how to fly a "real" jet. And I can't help but see that fear realized in the AF447 disaster.

[Turbine D]

@ JT,

From what I have read about the A330/340, IMHO, both possess static and dynamic stability to the point that in the worst situations, the aircraft is flyable. If it were not, I don't see how it could of been certified in the first place. I think the Airbus folks, designers, engineers, aerodynamicists and software folks thought of virtually everything to enable this, complicated as it may seem or be.

The worst two cases would be Direct Law and/or complete loss of electrical power.

Direct Law - In pitch direct law, elevator deflection is proportional to stick deflection and, in all configurations, max elevator deflection is a function of CG. This should be a transitory phase prior to PRIM reset and re-acquisition of Alternate Law. There is NO automatic trim meaning you have to use manual pitch trim. The yaw damper still provides yaw damping but gives minimal turn co-ordination. So protections of g, pitch attitude (manual pitch trim is required), high alpha, high speed, bank, MLA, turbulence, low energy and AP are all lost. But, the aircraft is flyable with care.
Should a complete electrical failure occur, mechanical pitch control is through the THS using the trim wheel. There should be caution here as if the CG is back there is a pitch up bias, if the CG is forward there is a pitch down bias. Manually operating the trim wheel requires gentle and smooth movement as the THS is a large aerodynamic surface. Mechanical lateral control is the secondary effect of rudder pedal inputs. The BYDU provides Dutch roll damping.
An example of an event which would put you in Direct Law would be a double engine failure, which at high altitude cruise, would probably mean that you will need to descend in a controlled manner to a lower altitude to initiate engine restarts.

I would say a good example of a unstable large aircraft without FBW computer controls would be the B2 USAF bomber. If the computers quit, IMHO, the aircraft would not be hand flyable.

Just some thoughts and opinions from a non-pilot, engineering type.

[rudderrudderrat]

Hi Turbine D & JT,
An example of an event which would put you in Direct Law would be a double engine failure,
Direct Law would occur only after putting the Landing Gear down. Up until then, you'd be in Alternate Law.

The aircraft is only statically neutral with the aid of the FBW computers. In Direct Law (stick deflection proportional to control surface deflection) they are (beautifully) dynamically stable.

[AlphaZuluRomeo]

Again, I may well be completely wrong, but my interpretation of "limited pitch rate feedback" would be that the alternate law value of 'a' is different from normal law.
OK thanks again :)
As I said earlier, I'm not that fond of maths. Would you be so kind as to "translate" what impact will a different 'a' value have (in AF447 scenario, and/or in general)?

I believe I've read somewhere that the different laws only affect the flight control system interpretation of side stick inputs. The autopilot commands are processed outside of the laws. Protections override side stick as well as A/P commands.
Yep, read that too. A/P issues deflection orders directly, sidesticks issue manoeuver demands which are translated into deflection orders by the flight controls computers/laws.

Regards.

[rudderrudderrat]

Hi AZR,
Would you be so kind as to "translate" what impact will a different 'a' value have (in AF447 scenario, and/or in general)?
I've only ever flown in ALT LAW in full motion simulators which do not simulate realistic g loads. (constant 1 g felt in turns & TCAS events with smart pull or push etc. The pitch attitude of the box changes to simulate horizontal accelerations; and the box moves up and down within the travel length of the jacks to simulate turbulence).

There is no perceptible difference in pitch control when flying in ALT LAW v Normal Law. Roll control is however noticeably different - if feels like a conventional aircraft.

[philip2412]

Sometimes i`m going really mad here.Although my english is good enough for the daily talk, i`m not really able to explain the psychlogical aspects i see in this crash like i could do it in german ; and that drives me crazy.
I´m no pilot etc. so why is he posting in the tech log,some may ask ,among all these profs and not in rumours % news ?
I can tell you. I`m feeling well here,because all in all it`s a serious discussion.
and no, i`m not here because there is a need for me to lift up my selfconfidence among the gods of flying and others.
So i can`t say much about the tech.aspects,but i comprehend what is said.
Thank you for your patience with me and sometimes recognizing my posts !

Back to business.

I´ve read a few hundred accident invest.reports and there was always a chapter about the prof.career of the pilots and what they were doing in the 48-24 hours before the flight and their behaviour with colleagues in duty.
This i miss here. so why ? Bad talking about gone people not allowed.The others were also mostly dead.
So why it is missing here,quite unusual.

[RetiredF4]

When discussing the different laws and its effect to the flight control system it is imho important to know and accept, that there are different Alt Laws available . In the last few post those differences didn´t get any attention (see my last post).

ALt Law 2B differs substantially from the other alt Laws, as all protections except load factor protection is lost. The biggest difference being, that in this Alt2b law the FCS works along the Nz law with no high speed stability (VMO2) or low speed stability protection (Vc prot) present.

Here the details of those protections in ALt Law (not in Alt2B):

Vc PROT law
This law, elaborated in the FCPCs, can be engaged in the flight and flare
phases, in the event of loss of the ALPHA1 law. It replaces the Nz law when
the aircraft speed becomes less than a threshold (Vc PROT).
A pitch order on the side stick then directly commands an elevator deflection
order to which a stability order with limited authority is added. The gains
of the Vc PROT law depend on the slat and flap position.
The purpose is to regain a positive static stability when approaching stall.


High Speed protection
This law, elaborated in the FCPCs, can be engaged in the flight and flare
laws. It permits, while staying in the Nz law, to add to the pilot’s orders a positive load factor when the aircraft speed or Mach number exceeds a certain threshold. In normal conditions (VMO1 law), the pilot’s authority is reduced in the nose down direction in order to make this protection not overrideable.
In degraded conditions (VMO2 law), the pilot’s authority is not reduced.
The purpose of the high speed protection is to limit speed or Mach excursions
beyond VMO or MMO, by adding a positive static stability.

Both those limited protections had not been available.

ALTERNATE LAW WITHOUT PROTECTION
In this case, the pitch protections are lost except the load factor protection.
This alternate law without protection is activated in the FCPCs after a triple
ADR failure.

When discussing the the stability and control issues as well as the stall entry of AF447 that point makes quite a difference. It´s the cause, that a SS in neutral on the way up to the apogee would have changed nothing, as the Nz-Law would have been active all the way into the stall. It may also be the reason, that in Dozys experiment in the A320 simulator a permanent stick force was required to maintain the pitch into the stall, or that the THS trim stopped, as VCprot worked against it or that PJ2 couldn´t achieve the same pitch as AF447 did in his simulation.

It might also make the difference between some of the other UAS flightpath excursions gone well.

If i would have to grade the handling in the different laws from a theoretical standpoint, it would be kinda

- Normal Law (artificial neutral stability with full protections)
- Alternate LAw except ALT 2b (artificial neutral stability with limited protections)
- Abnormal law (artificial neutral stability with limited protections without autotrim)
- Direct Law (natural positive stability)
- Alternate Law 2b (artificial neutral stability without protections except g-load protection)

But again, i didn´t fly that aircraft, but i doubt that all pilots are familiar with the consequences of all the different laws, as graceful as they may be (gums i´m with you on that one).

Edit:
It would be interesing to know, if the law Alt2b changed intermittently when the speeds came back on line or the above limited protections reactivated itermittently.

[HazelNuts39]

Would you be so kind as to "translate" what impact will a different 'a' value have (in AF447 scenario, and/or in general)?
Again my understanding, and I may be wrong. With stick free the Nz law tends to maintain essentially the current trajectory at approximately 1 g (nz=0). If that trajectory is such that the airplane decelerates, it will have to pitch up to maintain approximately 1 g at decreasing airspeed. The pitch rate q depends on the rate of deceleration dV/dt. It will not quite maintain 1g but it will settle for nz = - q/a, i.e. an incremental load factor that is slightly negative, depending on the value of 'a'.

P.S.
For example, at FL350, M.6, 205t and decelerating at 2 kCAS/second, the pitch rate maintaining 1g is 0.27 degrees/second.

[jcjeant]

So why it is missing here,quite unusual.
The answer at your question is in the BEA meeting with the press (the day they released the final report)
One journalist asked same question as yours..
Answer BEA:
They made researches about what made the crew in Rio
They find nothing interesting or related to the crash ..... so nothing of value to put in the final report ......

[Rockhound]

Lyman,
What I said about the C chord generator burning out was tongue-in-cheek. I know nothing about how it functions. As I said, does it really matter?
JCJ,
Regarding the meaning of the captain's "prends ça", Otelli wrote that it is difficult to know what he was referring to but the BEA investigators favoured the idea that it was the FPV.
Why do you call Otelli's book "useless"? Not only does it contain the entire CVR transcript but the transcript is an improvement on the bare-bones version released by the BEA in that the reader gains an impression of the tone of voice used (exclamation, question, etc.). Also, Otelli has filled in some of the blanks in the BEA release (whether that's accurate or not is another matter, of course). Finally, Otelli has keyed the CVR to the FDR and thus provides background to at least some of the crew's statements and actions.
Clearly the key to the tragedy of AF447 is the CVR transcipt. For those of us who possessed a copy of Otelli's book (published in late 2011), the release of the BEA final report was very much an anti-climax.

[rgbrock1]

jcjeant and philip2412:

Gruess di'.

In the final BEA report it is written that the investigation was not able to ascertain what the 3 pilots were doing for the 72 hours they were in Rio. PF did have his wife on board AF447 and she spent his layover time with him in Rio.

What else the three crew members did was not able to be determined.

[Lyman]

Hi Rockhound...

Tongue likewise in cheek in my question...

Is it important? Yes, and no. To a technical person, whose specialty is ergonomics, perception, sensories, etc. But to you? Perhaps not. The take away from the report is that it is minimalistic. In its brevity, BEA allows popular comment and perception to remain in the discussion, rather than exhausting all reasonable questions. An exquisitely important CVR artifact, the comments re: ambient temp in cockpit could have several causes, where is this addressed in the report. Where is the elimination of possibilities, and in the elimination, the establishment of a probable cause? The cause is allowed to be dictated by PPRuNe, evidently, incompetent pilotage....

[jcjeant]

Clearly the key to the tragedy of AF447 is the CVR transcipt.If as you think the transcript is the key to the accident of AF447 ... I'm certainly not going to consider the writings of Otelli but instead .. will consider the BEA transcript
In addition to his writings about the transcript is not accurate .. thus we have seen in the transcripts appearing in the final report
We have many "Otelli" in this forum (or at least able to write a book like Otelli) .. they can write it .. this will not change a ounce about what happened and what is engraved in stone in the BEA final report ...
The only place where the final report can be .. (maybe) challenged .. is the judicial court ...
And be sure that Otelli will not spoke a word there

[Organfreak]

The cause is allowed to be dictated by PPRuNe, evidently...

I'm sorry, sir, but....
Whaddaya, NUTZ????

:yuk:

[gums]

Don't know if someone else posted this link, but seems relevant.

Airbus reviews instrument logic in aftermath of AF447 (http://www.flightglobal.com/news/articles/airbus-reviews-instrument-logic-in-aftermath-of-af447-374484/)

What I don't understand is why the flight directors don't just display last attitude or maybe a benign pitch attitude when the air data goes to la-la land.

Then there's all the audio warnings and AoA issue.

Decent article, IMHO.

[roulishollandais]

@Gums,
Thank you for the three ref.
About FD, I can find no correlation between the pilot action and the parts of FD displayed. Does anybody ?
The problem was C* as you pointed it with retiredF4, and now the BEA final report. Thanks !

@ChisN,
Thank you for the strange attractor (of course !) it is such one effectively, but not for the famous Lorenz system but A330 ! (to compute!) It is an important concept for stability of non linear dynamic systems.

[OK465]

from post #392, clandestino, (a few days ago)

Seems that FCS gives up restoring itself back to normal law after it detects long lasting ADR disagreement, however AFCS keeps checking indefinitely and will restore itself as soon as two ADCs agree, not necessarily at correct value. Page 86 of the report refers.

(my bold)

It appears the 'magic' agree number is ANY two ADR's <20 knots difference, no matter how 'off the wall' the actual values are as long as they meet other engagement criteria. [Of interest, this can be the two PFD displayed values OR one of the displayed and the other not selected ADR value (i.e. the other displayed PFD >20 knots difference with both 'agreeable' ones).]

This appears to also be the point at which the FD's return.

Pardon if this figure has been provided before in other threads, I may be late for dinner here, but does anyone have a reference for confirmation of this value, if in fact it is correct? A33Zab?

@A33Zab: With ALT2(B?) 'latched', the SPD LIM flags displayed and no characteristic speeds displayed (including no VLS), and no FMGEC VLS (dashes), the A/P pb latching appears to depend only on 2 ADR's within 20 knots, not FMGEC VLS. The A/P pb apparently latches with the 2 values in 'agreement' below actual VLS. Is there a reference somewhere? Once again, apologies if it has already been provided previously.

It would be interesing to know, if the law Alt2b changed intermittently when the speeds came back on line or the above limited protections reactivated itermittently.

@RF4: The report states that ALT2B was 'latched' so I would assume there were never any intermittently available speed stability functions, but I erroneously thought the same of the A/P pushbutton. :}

[Lonewolf_50]

If the FD was intermittently on and off, working and not working, I may have a better guess at the answer to my old question regarding the PF: what was he seeing?

If what I guess is close to right, then I begin to understand another factor in his confusion and frustration, particularly if his habitual instrument scan relied heavily on the "bird."

Mind you, this is guessing. Maybe a puzzle piece that fits better than others, maybe not.

[rgbrock1]

Perhaps, Lonewolf, the PF did not comprehend what he was seeing. He probably never saw things on that flight deck that night, before in his entire career.

This possibility, together with sensory overload, preoccupation with weather, ignoring of various "bells and whistles", the so called startle effect, his losing focus on the task at hand (fly the damn plane), little communication with the PNF, piss-poor CRM (including the Captain), total lack of situational awareness and a host of other issues and is it any wonder he was pulling back the entire time? To this non aviator it would seem the guy was scared ****less and had no idea what the hell was going on around him.

When the **** hits the fan, as I learned several moons ago, it's fight or flight. He went the latter path. He didn't choose it though. It overwhelmed him.

[Lyman]

rgbrock1. You have spent a paragraph focused on PF and what he felt, how he may have felt it, and what he may have seen and done. That is perfectly ok. There is a lot of it, and a lot of repetitive opinions on feelings, startle, fatigue, experience, what they did prior to launch, ad nauseous, again ok.

"What is that smell?". "it's hot.." "Yes it is gotten hot in here..."

"Ozone"....". (end of). Re: the increase in cabin temp? Nothin'......

STALLSTALLcricket... What is that? ( no answer, no answer, no answer)

BEA "probably his reaction to STALL WARN" fine, case closed, end of...

No answer to cabin calls, none... No problem? end of......

Constant and vigorous speculation on the pilots, mostly about things that will never be known,,,,, Mechanical issues? Not so much...

[DozyWannabe]

Because the physical evidence recovered does not correlate with mechanical or electrical problems (aside from the pitot tubes), and no amount of wishing will make it so.

Remember, just because it's not in the final report doesn't mean it wasn't investigated.

I ask again - what makes it so tough for you to believe?

[john_tullamarine]

Ref this post (http://www.pprune.org/7303635-post575.html).

The aircraft is only statically neutral with the aid of the FBW computers. In Direct Law (stick deflection proportional to control surface deflection) they are (beautifully) dynamically stable.

This is the bit with which I'm having difficulty although my reading of the various links (and thanks to those who PMd/emailed other suggestions) may answer my questions ..

Neutral static stability infers a more aft CG than "normal". The box then can give the pilot an impression of stability (and, at the end of the day, it is this impression that is required). If, now, the box departs controlled operation .. the aircraft CG is still where it was (until it can be moved) and the pilot potentially now is stuck with neutral static stability .. OK if you recognise it and know what to do .. but, otherwise, a recipe for rapid disaster ...

[mm43]

@OK465;The A/P pb apparently latches with the 2 values in 'agreement' below actual VLS.If you can follow the [/URL]logic schematic (http://www.pprune.org/tech-log/489774-af-447-thread-no-9-a-19.html#post7295037) posted by A33Zab, you will note there are a number of variables that must meet specified values before the p/b can be effectual.

The latching of ALT 2B was a result of diverging ADR speeds. ADR2 was nominated the "median" value and when speeds hadn't returned to within 50KTS of the median in 10 secs, law reversion to ALT 2B occurred and remained for the rest of the flight.

A33Zab has previously pointed out that the FD may be engaged on the ground in V/S mode, and on AF447 the A/P was inhibited due to CAS < VLS from 02:10:08.

[U]AP Engage is inhibited:
if abs(φ) > 40°,
or θ < -10°, or θ > +22°,
or CAS < VLS,
or CAS >(VMO/MMO or VLE/VFE)

In respect of the FD Bars, they do appear to have been available when 2 ADRs (also 2 IRs) agreed within 20 KTS. The same agreement is also a provision of A/P engagement, plus FMGEC, FCPC (also no breakout by SS or pedals), plus the φ, θ and CAS conditions being met per the schematic.

[bubbers44]

John, I agree, neutral stability means the CG is at it's aft limit area to save fuel but it needs a computer to keep it stable. A pilot would have a hard time to keep it at a constant altitude. I guess a good pilot could still fly it by hand but it would be difficult. They would probably with no autopilot transfer fuel forward to make it easier to fly.

[john_tullamarine]

neutral stability means the CG is at it's aft limit area to save fuel but it needs a computer to keep it stable

Not quite right. For a conventional aircraft (and I presume this is what the Airbus becomes in the event that ALL computers roll over and die), the aft CG limit may (amongst other requirements) be limited to give an acceptable positive static stability .. neutral stability would be a fail and require either a further constraint of the aft limit or another flight test engineering fix.

It follows that, if the CG is sufficiently far aft to result in neutral stability, then it wouldn't be certificatable or, perhaps, the probability of box failure demonstrated at certification is sufficiently low to be acceptable.

However, this latter consideration may be tied in with the present mishap - inextricably. Are we not all concerned with the possibility that this crash may have been involved with events so out of left field (but only because of presumptions regarding training and competence standards) that the original certification program may not have considered them at all ?

I don't know what the certification story was for the Airbus FBW machines but would sure be interested to find out ..

A pilot would have a hard time to keep it at a constant altitude

True, but that's only a part of the problem. The typical pilot, faced with a sudden deterioration in the stability he/she feels/sees is more likely to rip the wings/tail off while trying to figure out what might be going on ..

a good pilot could still fly it by hand but it would be difficult

More a case of needing to recognise the problem and then be aware of/trained in the changed techniques required to fly the aeroplane. TPs cover this during their training course and there are documented cases of the occasional TP having to drag a statically unstable aircraft around the patch to get it back onto the ground .. but for Captain Average Joe Pilot .. the story, in all probability, is going to have an unhappy ending.

[bubbers44]

We did the fuel transfer thing to the aft tank in the 70's in a Lear jet. You get level at FL410, set power for .82 mach, transfer fuel aft and bring back the power to maintain speed as speed increases, FREE SPEED.

Aft CG as everybody knows means the horizontal stabilizer doesn't have to push down as much because of the forward fuel.

[john_tullamarine]

.. but, I suggest, with the aft tank loaded .. the aeroplane was still statically stable (ie still had an acceptable stick force gradient) for certification ?

[bubbers44]

John, that is why I said the area of the aft CG limit, not at it. All aircraft have to be certified to meet requirements.

[john_tullamarine]

Confused a tad by your comment. Presumably, with aft tank loaded you still were within the aft CG AFM limit ? At the published aft limit, one would still expect to see acceptable LSS.

[gums]

I'll go out on my normal limb and tell all that the FBW system on the 'bus can't provide "simulated" or "apparent" static stability. The jet is either stable or not, and it is not like that little thing I flew long ago which was actually unstable until 0.95 M and depended upon HAL to keep the pointy end forward.

If we are talking about little or no speed stability because HAL is trimming for a gee versus an AoA ( just like the Viper), then you may think you have "neutral" static stability, but you don't. The 'bus has positive static stability throughout a good combination of cee gee versus center of aero pressure, but never has inherent aerodynamic negative static stability.

I agree with those here stating that it would never have been certified within any realm on the charts indicating negative static stability. Even AF447 showed positive static stability at 40 degrees AoA or whatever the exact value was. Push forward and eventually recover. What we DID SEE was an AoA and cee gee that allowed it to remain fairly stable while stalled, courtesy of HAL, which was constantly commanding nose up and trimming the THS to reach the nominal one gee command, hands on or hands off. Only forward stick and maybe manual THS trimming could have enabled a recovery.

God, but I would love to get some of you in my old jet and show you the differences between the older jets and one with a FBW system with all the "limits"/"protections" and fly it to the limits. Knowing a lot more about the 'bus now than two years ago, I would relish the oppo to do the same thing in the beast. As Doze is fond of reminding me, our jet was designed with different goals/missions. Nevertheless, it was the first one with FBW, no mechanical back up, and we all became test pilots for a year or two, even after 4 or 5 years of development and testing at Edwards.
out,

[OK465]

In respect of the FD Bars, they do appear to have been available when 2 ADRs (also 2 IRs) agreed within 20 KTS.

@MM43:

When ALT2'something' latches as a result of multiple 'ADR disagree', I can count down 1 knot at a time and when the difference between the 'median' ADR and the next closest reaches 19 knots, the FD's return and the AP 1+2 inop status is removed, regardless of the magnitude of the remaining ADR discrepancy. The A/P pb can then be engaged, even though ACTUAL speed (CAS) is below ACTUAL VLS. VLS is neither displayed nor indicated on the FMGEC landing phase PERF page. It is dashed and appears not to be computed.

As soon as I take the speed discrepancy back to 20 knots or above, the FD's go away and the A/P pb cannot be engaged.

Either I'm not really in ALT2B, which, on the surface, is problematic to determine, or there is a potential Level D problem, always a possibility, or 20 IS the magic number.

This is what I'm trying to determine. :confused:

[Linktrained]

C of G

There was quite a lot about C of G about a year ago in Thread 5 #394 ...etc. Some of it IIRC implied that fuel was transferred " in chunks" forward for use in flight whilst keeping the C of G within the normal "in flight limits" by some margin. I would guess that during the transfer of each "chunk" the aircraft would respond to the change of C of G with a change of speed or F/L , normally adjusted by A/T and A/P - but if these are not available then manual control would seem more sensitive.

( On a York hand flown, it could feel as though the passengers were playing cabin football, with a goal at each end of the cabin !)

[bubbers44]

John, yes I meant within aft CG limits if that was what you were asking.The LSS thing isn't familiar to me but it must have something to do with stability and CG. Us yanks use different terms so help us out.

[Turbine D]

CG at time of event:

CG is the red dot representing 28.7% Prior to TO it was 23.3%


http://i1166.photobucket.com/albums/q609/DaveK72/cg.jpg

[john_tullamarine]

God, but I would love to get some of you in my old jet

Yes, please. Only FJ I've been in was an RAAF ARDU Mirage in the early 70s and that was good fun.


The LSS thing isn't familiar to me

Apologies. (Longitudinal) Static Stability. Basic thing for (required) positive stability is

(a) maintaining slower than trimmed speed requires the pilot to pull
(b) maintaining faster than trimmed speed requires the pilot to push

[bubbers44]

Thanks John, I never encountered that way of approaching it before.

[john_tullamarine]

That's the way the testing and measuring is approached ..

The typical pilot training thing about strange balls in teacups is useful if explained appropriately but, near invariably, it is a case of the blind leading the blind and the explanations tend to be more fanciful than useful.

Stick force for positive static stability can be thought of in terms of "if I relax the load, the aircraft initially would seek to return to the trim speed".

In terms of balls and cups .. the analogy is "if I let the ball go .. its initial movement would be in the direction of the bottom of the cup".

Either way static stability is to do with the aeroplane's being at a fixed off trim attitude and looking at what it might want to do if you were to let go of the stick/ease off the stick load .. dynamic stability looks at what it actually does.

[mm43]

@OK465; The A/P pb can then be engaged, even though ACTUAL speed (CAS) is below ACTUAL VLS. VLS is neither displayed nor indicated on the FMGEC landing phase PERF page.Agreed!:ok:

But there is one more set of variables (includes CAS > VLS) to be confirmed before the A/P will actually engage, and that is not met. The logic presented by A33Zab clearly shows that with regard to the A/P the CAS/Pitch/Roll condition is the final inhibition - irrespective of FMGEC, other than when Pitch Angle Protection is active in Normal Law.

[CONF iture]

Regarding the meaning of the captain's "prends ça", Otelli wrote that it is difficult to know what he was referring to but the BEA investigators favoured the idea that it was the FPV
The BEA did retract on that but did not propose any other possible explanation ... ?
In a 6 seconds period, the captain said it once and the PNF twice - I cannot figure out what they were talking about ... ?
That's a period of time when the PF was full back stick !
BTW that part of the CVR has changed since the third Interim Report ...

Also, as mentioned earlier by Lyman, why the captain is telling "AP OFF" at time 2:13:53 ?
What is that 'bruit de selecteur' ... an AP that is selected would make such a 'bruit' ...

That BEA is really not curious, at least publicly.

Another point is that total confusion related to the vertical speed indications or possible intermittent lack of it.
The comments made by the crew suggest how that information was erratic when displayed ... How were behaving the altimeters ... ?

Otelli's book ?
I should read it before commenting further but have no intention to pay for that ... Any link for the CVR part ?

[gums]

Thanks for the chart, Turbine, it's the one I used making my assertion that the jet was well within the cee gee envelope.

To JT, I tink you have to further explain about LSS. So if I am below the trimmed AoA, the plane noses up to get there all by itself if I let go. And vice versa. So trimmed for 80 knots in my Cessna and I am zooming along at 100 knots without re-trimming, then the thing pulls up if I relax the wheel/yoke/stick. U.S. nasal radiators like 'bird are very familiar with this, as it was the way they made their approach to the deck - they trimmed for AoA and used power to control rate of descent.

For the 'bus drivers here. you could try this in the sim, but the control laws would fight you. Normal law is not heavily biased for AoA, and the auto-throttle would thwart you. But I guess ya gotta play the cards that you are dealt.

[john_tullamarine]

So if I am below the trimmed AoA, (ie motoring along the aerial freeway faster than trim speed) the plane noses up to get (back) there (somewhere near trim speed - within a reasonable tolerance) all by itself if I let go (strictly, if you ease off the stick load gradually). And vice versa. So trimmed for 80 knots in my Cessna and I am zooming along at 100 knots without re-trimming (but holding a pretty decent push stick force as you descend - test normally would be for a fixed thrust setting), then the thing pulls up if I relax the wheel/yoke/stick. U.S. nasal radiators like 'bird are very familiar with this, as it was the way they made their approach to the deck - they trimmed for AoA and used power to control rate of descent.

[My red additions above for additional wordiology confusion].

The current test procedure for FAR 25 is given in the FTG AC 25-7B (http://www.faa.gov/documentLibrary/media/Advisory_Circular/25-7B.pdf) starting at page 109.

Similarly, for Part 23, the FTG is at AC 23-8C (http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC%2023-8C.pdf) starting at page 78. (be warned - 14MB)

[RetiredF4]

Imho some of you are on the wrong path concerning the stability issue.

Fact is, that BEA brings in the "neutral stability" issue and they wouldn´t have done it for no reason.

This neutral stability is not a built in by design into the airframe or caused by shift of CG (trimtank), it is done by managing the position of aerodynamic pressure by the computers with the elevators in the short term and the THS in the long term. Therefore i did use the term "natural" and "artificial".

Gums described it in his words.

Gums
If we are talking about little or no speed stability because HAL is trimming for a gee versus an AoA ( just like the Viper), then you may think you have "neutral" static stability, but you don't. The 'bus has positive static stability throughout a good combination of cee gee versus center of aero pressure, but never has inherent aerodynamic negative static stability.

While the new generation of combat jets are "natural unstable" and are made stable by the computers, it is quite different in the A330. It is natural stable with positive static stability (See the graph posted by TurbineD) even when computers change CG a bit by transfering fuel to or from the trimtank. With the automatic THS trim besides the elevators the computers have a formidable tool to change the aerodynamic pressure, hence the airframe is kept in neutral stability all the time.

In a conventional aircraft it is the same situation when you have the aircraft perfectly trimmed, with one big difference. The trimmed conventional aircraft is speed stable and will return to equilibrium if disturbed out of that trim condition, the discussed A330 is not speed stable but flightpath stable within limits defined by the built in flight envelope protections.

JT
However, this latter consideration may be tied in with the present mishap - inextricably. Are we not all concerned with the possibility that this crash may have been involved with events so out of left field (but only because of presumptions regarding training and competence standards) that the original certification program may not have considered them at all ?

At least BEA mentions this neutral stability, wether as excuse for the problems the crew faced, as a hint to the manufacturer that the reversion sequence and the documentation needs a look up, or as a hint to better training and understanding of the resulting flight behaviour when vital inputs are lost? Or any other reason we can think of.

JT
neutral stability means the CG is at it's aft limit area to save fuel but it needs a computer to keep it stable

As described, here with the A330 it´s vice versa. The aircraft has a natural positive stability, it needs the computers to keep it in the neutral region.


JT
However, some of the posts appear to be suggesting that the degradation can extend to nil box assistance and a statically unstable aeroplane.. that's my problem at the moment.

Imho the "Nil Box Assistance" is not the problem, as the aircraft would then (with manual THS trim) be a natural positiv stable airframe.

The problem here is, that with all protections except load factor protection lost the aircraft was kept in this neutral stability by the computers and the crew could not cope with the responsiblity to keep the aircraft within the flight envelope.

See RR´s post below.

rudderrudderrat
The aircraft is only statically neutral with the aid of the FBW computers. In Direct Law (stick deflection proportional to control surface deflection) they are (beautifully) dynamically stable.
Exactly

JT
This is the bit with which I'm having difficulty although my reading of the various links (and thanks to those who PMd/emailed other suggestions) may answer my questions ..

Neutral static stability infers a more aft CG than "normal". The box then can give the pilot an impression of stability (and, at the end of the day, it is this impression that is required).

Imho not necessarily, as explained before. The aft CG helps in saving fuel, but is not necessary for creating the neutral stability. The continuous autotrim is creating this permanent neutral stability with the help of the box.


If, now, the box departs controlled operation .. the aircraft CG is still where it was (until it can be moved) and the pilot potentially now is stuck with neutral static stability .. OK if you recognise it and know what to do .. but, otherwise, a recipe for rapid disaster ...


The CG doesn´t change except for the fuel in the fin, the location of the center of aerodynamic pressure is constantly changing and keeps the aircraft in neutral stability until the degradation drops into direct law. Then you might have an aircraft completely out of trim, but it is basically now an aircraft with positive static stability. As in direct law only the trim wheel is available for longitudonal control, you wind it where it needs to be and the aircraft would be no longer flightpath stable, but speed stable.

Whereas in ALt law2 the aircraft was still kept in neutral stability by the box and was flightpath stable, but the necessary protections to make such a system safe (including the backup system "aircrew" ) were not working, thus leading to the flight-envelope excursion.

Bubbers44
John, I agree, neutral stability means the CG is at it's aft limit area to save fuel but it needs a computer to keep it stable. A pilot would have a hard time to keep it at a constant altitude.

True for a conventional aircraft, ts different here.

I hope Owain Glyndwr can cut in and correct where i´m wrong or to add where necessary.

[rudderrudderrat]

Hi JT,
Ref your post 594

I've confused you with the wrong terms.
The aircraft feels like it is neutrally dynamically stable in normal law, and slightly positively stable in ALT law.
The only time we feel Direct Law is after the gear is down. I've never handled it at aft c o g in direct law, but presumably the gear drag couple would help.

[john_tullamarine]

Franzl,

I am uncomfortable with your thoughts regarding neutral stability although I have no problem with the Airbus's maintaining a constant flight path hands off.

Indeed, one of our PPRuNe number was in the Regulator's FT chair when the A320 was introduced to AN in Australia and he was quite ecstatic about the aircraft's capabilities at the time of Australian certification.

However, I acknowledge that my FBW knowledge is limited so I guess I will have to dig into the books and read up some more on FBW bits and pieces ...

[RetiredF4]

John T,

there are differences between the A320 and the A330, also concerning the reversion of laws.

I´m not sure wether i should be uncomfortable about the system itself or about the general knowledge about those systems and the asociated training by some operators including their crews.

[john_tullamarine]

Franzl,

The general dumbing down of things piloting is an extreme worry to most of us. If the systems design folks could guarantee that they get it all correct (which, of course, they can't .. and don't) it might be a different matter .. but, until they can, the folks up front are the last ditch defence and if they don't know much beyond "light A ON .. button B PRESS" we are better off going fishing.

The beancounting fraternity has a lot to answer for I suggest.

[Thanks for the PM offer]

[Lonewolf_50]

Understanding "speed stable" versus "flight path stable"

If the driving concern is "flight path stable" then I'd gather that the system makes small speed corrections, or small corrections that manifest themselves in small airspeed changes, continuously. These changes would dampen until they reached vitrually zero when we reach desired altitude and mach/speed for a given sector of the flight. This would include automated and minor corrections of the power setting as part of this flight path seeking method.

Do I understand your explanation correctly, or am I simply confusing myself?

To whomever posted flight global article (http://www.flightglobal.com/news/articles/airbus-reviews-instrument-logic-in-aftermath-of-af447-374484/): thanks! :ok:

This provides me with a very nice explanation points for some of the laymen I know who are curious about this accident.

[slats11]

The general dumbing down of things piloting is an extreme worry to most of us. If the systems design folks could guarantee that they get it all correct (which, of course, they can't .. and don't) it might be a different matter ..

You know, this is a broader cultural issue. We are seeing the exact same paradox in medicine. Everything is being reduced to autopilot with clinical pathways and guidelines. This approach inevitably de-emphasizes critical thinking, and clinical decision making skills are being lost as a result.

This approach standardizes care and produces better outcomes - most of the time. And so risk managers and administrators and legal departments love this stuff.

But (and there is always a but), if the patient gets misdiagnosed and put on the wrong pathway, or if the pathway does not address an uncommon set of circumstances particular to an individual patient, the physician is left with nothing to fall back on.

The physician blames the author of the pathway for not anticipating an unusual scenario, the managers blame the physician for not recognising s/he was out of his depth. The solution is to invariably to revise the guideline - because that is the only component of the system amenable to change.

And so it will be with AF447. Some improvements will be made to the automation. And they will be an improvement. But the underlying problem will be papered over.

[jcjeant]

EYbsIJO6MjA

[Lyman]

In the building business, a similar 'pathway' process is utilized. The concept is called the critical path, and sounds similar to the approach in medicine. It is applied in each project, drives scheduling and assessment, and must be monitored constantly by process (project) managers.

If applied (very) loosely to 447, one starts to appreciate the British expression: "losing the plot". I hope the comparison to construction does not offend, in Medicine, as in Aviation, lives are on the line moment to moment, and generally, losing the critical path does not cost lives.....

But in investigation, the critical path is apt, and perhaps could be used to better results if it were applied....

It depends wholly on the mission.

[A33Zab]

When ALT2'something' latches as a result of multiple 'ADR disagree', I can count down 1 knot at a time and when the difference between the 'median' ADR and the next closest reaches 19 knots, the FD's return and the AP 1+2 inop status is removed, regardless of the magnitude of the remaining ADR discrepancy. The A/P pb can then be engaged, even though ACTUAL speed (CAS) is below ACTUAL VLS. VLS is neither displayed nor indicated on the FMGEC landing phase PERF page. It is dashed and appears not to be computed.





AMM 22-11-00 PB 001 AUTOPILOT/FLIGHT DIRECTOR (AP/FD) ENGAGEMENT D/O.

Par. 2.C:

(2) AP engagement inhibition and disengagement logics
(a) Pitch and roll angle limits
- Roll angle

AP engagement is inhibited when abs(phi) > 40°
AP is automatically disengaged when abs(phi) > 45°.
- Pitch angle

AP engagement is inhibited when theta < -10° or theta > +22°
AP is automatically disengaged when theta < -13° or theta > 25°.
(b) AP engagement is inhibited in flight when CAS < VLS or CAS > (VMO/MMO or VLE/VFE).

(c) AP engagement is inhibited when the FMGEC receives the "pitch angle protection active" information from the FCPC.

[PJ2]

slats11;
You know, this is a broader cultural issue. We are seeing the exact same paradox in medicine. Everything is being reduced to autopilot with clinical pathways and guidelines. This approach inevitably de-emphasizes critical thinking, and clinical decision making skills are being lost as a result.

This approach standardizes care and produces better outcomes - most of the time. And so risk managers and administrators and legal departments love this stuff.
Yes, a very good observation indeed. Medicine and aviation have a great deal in common when it comes to "passenger/patient" care.

We could say it is cultural but I think of it also as a political economy which has been developing since the early 70's, sometimes loosely known as "neo-liberalism" - the notion that privatization, de-regulation, and "free enterprise" will provide "market solutions" for all problems including the ones you have just outlined.

Nothing could be further from the truth and further from what is needed.

Like all social/economic phenomenon it's not all bad but recognition of the worst effects of a neoliberal political economy in the areas under discussion is only now taking hold.

If the regulators of the western world are not tuned into these notions, massive safety initiatives like SMS could be the de-regulation of safety rather than an enhancement of safety using modern data technologies and new knowledge regarding psychology and human factors in high risk enterprises.

The notion of "ethics" has all but evaporated in this fundamentally-instrumental economy. It is a shame that the term "business ethics" is often joked about as an oxymoron. However there are encouraging signs of change, beginning first with awareness that untoward outcomes in high-risk endeavours do not favour high profit or shareholder satisfaction nor do such events sustain the viability of an organization which normalizes deviance for short-term solutions.

A "prescriptive" approach where responses are patterned, quietly assumes that given sufficient rules and flow-charts for programmed diagnoses and actions, that anyone with a bit of bread-and-butter training, (MCPLs...), can be plugged into a sophisticated system even within a high-risk environment, and succeed.

The notion of automation is a social phenomenon, not a technical description.

A flow-chart process works for ordinary cases, as you say and it does save time, money, guessing and lives.

But the regulators often hearken to, and follow, private enterprises' ways, and, assuming that prescriptive approaches actually work, download expensive responsibilities which are the rightful pervue of government, onto profit-centered organizations, assuming that they will willingly and effectively monitor themselves and act in safety's best interests. Further, none of this requires experience but mere adherence to policy and procedures. An audit by the regulator sometimes seems more focussed on process and documents than it does on "smelling the health" of the place.

A lot of people really believe that this approach works but try telling a VP of Flight Ops who's knocked around aviation for a lifetime and knows his or her stuff, that kind of nonsense. It is an aid for quick reference, not a replacement for knowledge, training and experience, none of which are valued nearly as highly today as a nice, organized shelf of perfect documents in everyone's office.

This isn't to denigrate the changes - I think in many ways they're better now. But addiction to paper and process without watching and knowing what's actually being done and not just written or said, makes the difference.

I think, as the saying goes, that those chickens are coming home to roost, but private enterprise, with government's assistance through and relative absence in the past, (it seems to be changing...but how?), and the elixir of short term profit, have taught the travelling public that airlines can fly people safely for $59 one way and that complaint is legitimate when airfares differ or increase by the cost of a McDonald's happy meal. Such standards are going to be extremely difficult to alter when the factors we are seeing against the background noise become stark.

I wrote the following on automation and pilots earlier this year:

Standards, the notion of professionalism and the career and the job of “Airline Pilot” all have changed since de-regulation, even more so since the 90’s, almost singularly through the hands of non-aviation, finance people.

These changes were likely well-meaning, intending to come to terms with economic challenges in an increasingly deregulated, speculative political economy. But the effects must be examined for what they are, not what was intended.

The present environment makes it very difficult for airline executives to plan and finance an industry which by its nature requires very heavy capital investments over long periods of time as well as investor patience.

Downward pressures on costs, wages, benefits and pensions remain significant on those areas of an airline’s operation which remain most “flexible”, in terms of reducing costs. The most “flexible” of all tend to be its labour force. The effect is now familiar to all employees, known as ‘the race to the bottom’. The relationship to fares and fare structures, outsourcing, reduced regulatory oversight and other factors is complex and well beyond examination here.

From a flight safety point of view, the effects of wholesale cost reductions in a high-risk enterprise usually do not show themselves right away and so they appear to be justified because “nothing happened”. The immediate rewards are, costs were ‘successfully’ reduced and the department manager looked good and met his or her quarterly reductions.

Quarterly Reports may be important to the life of the corporation but only convey a financial snapshot. Other systems reflect the health of the organization but they are rarely “attached” to the organization’s fiscal statements.

The effects and the results of a fiscal “cutting to the bone” on flight operations may only emerge years later. Changing trends in incident or accident rates are thus disconnected from their origin. Solutions may thus be incorrectly informed.

Is “automation” the problem?

Many observers, including pilots, have already stated that automation itself is not the problem. Having flown such automation for many decades I agree with this view.

Automation is just part of the kit for flight crews. The approach was always, “We fly an aircraft, we do not "manage a software platform". Just because a technology can be created to accomplish something does not mean that it should be adopted as natural or inevitable. Automation is a conscious choice made primarily by airlines and manufacturers and is essentially an economic one with flight safety benefits.

I and my colleagues were comfortable with automation because, as a colleague has stated, we flew older generation aircraft and knew how, and automation was an “add-on” which, like anything in an airplane, was always watched carefully.

We had the attitude that “the airplane was trying to kill us”; perhaps blunt but it remains an effective attitude for aviators, especially when the obvious benefits of full automation were in some minds beginning to eclipse the utility and even the definition of “pilot”.

In the seventies and eighties almost every departure and every arrival was hand-flown, sometimes to and from cruise altitude. Except for those flying versions of the B737 and MD80, nobody entering the profession today does that, nor is it emphasized anymore.

Encouragement to hand-fly and the “freedom to practice” was always offered by captains who knew the value of remaining cognitively engaged and situationally aware. However, very few took up offer, citing discomfort, especially when disconnecting the autothrust.

Automation was engaged just after takeoff and disengaged at around 400ft just before landing, just like the FCOM required.

In fact, one hand-flew the airplane at some risk should an incident have occurred while doing so. Hand-flying was, and remains, discouraged by airlines. It is not automation that is the problem – it is the absence of piloting the airplane, a physical and psychological act which creates a cognitive situational awareness that is not available otherwise.

I think a historical misunderstanding of what automation does and what automation’s capabilities are, which are quite spectacular and wonderful in my opinion, is quietly replacing a corporate understanding of what flight crews do and what their job and what their profession is. This shift in attitude towards pilots as "almost redundant to automation", has translated into a silent legitimation of what in some cases is inappropriate cost-control initiatives including the unwillingness to pay reasonably and otherwise ensure a reasonable career. It wasn't hard to imagine the outcome: Young people have taken note and are avoiding aviation as a career.

Because training is enormously expensive, (crews are non-productive during training, training itself is costly), time spent in training is focused on the one thing that is perceived to reduce costs, and that is automation.

As well, automation is viewed by the industry as a fatigue-management tool, (“the airplane flies itself” thinking), and therefore justifies reductions in both augmented crew requirements (in terms of how many) and the qualifications of those doing the augmentation, (in terms of experience and training). In fact automation is a superb fatigue-management tool, used appropriately but it is not “the third (or fourth) crew member”.

Because of inherent accuracies and predictability, ATC accepts and views automation as a flow-control and accuracy tool and, to accommodate greater traffic demands (in both time and space), design SIDS and STARS which have tighter tolerances for altitude, speed and route control, requiring the use of automation to ensure accuracy.

Automation’s complexity and training costs (crews are non-productive while in-training), requires that most recurrent training time in the simulator is spent in automatic flight. It is extremely rare to be given a hand-flown, raw-data, manual thrust ILS to limits. Hand-flying at altitude is simply never done; even the Emergency Descent (after a depressurization or verified bomb threat), is done on the autoflight system.

There is no time formally set aside for hand-flying and practicing one’s instrument scan. The expectation is that professional crews will develop this skill for themselves. The failure in such thinking is, there is no opportunity afforded to do so, not, at least, without risk should an incident occur.

The almost-complete absence of hand-flying has led to a state of affairs not discussed in the industry or by the regulator until AF447. While airline pilots flying international overseas routes might “fly” 700hrs per year, 99% of the air time (excluding takeoffs and landings) is under automation and actual manual stick time is only about 3 to 5 hours per year.

There are about two to five minutes during takeoff and initial climb in which the airplane may be hand-flown, (on autothrust), and between 40 seconds and two minutes during the approach and landing.

On international routes that would be done twice, perhaps three times per month. Domestic flights do more flight legs per month, but I cannot speak to how much manual flying is done.

An RP, (Relief Pilot) will fly manually even less because of the nature of the job and the qualifications, (Air France’s RPs are trained to take off and land. In Canada, the Relief Pilot is not legally permitted to sit in the front seats below cruise altitude. Therefore, a Canadian Relief Pilot receives no training in takeoffs or landings except in initial training. In one operation I am familiar with the Relief Pilot is trained to do the Emergency Descent from the left seat when relieving the captain.

Flying an airplane, either under autoflight or in manual flight, are cognitive and physical skills which must be practiced, but we have an industry which continuously is reducing the opportunity and the legality of hand-flying.

Automation as non-paid labour – the “third pilot” syndrome

The perception is largely held by non-aviation people who manage the business of aviation that "these airplanes fly themselves" and that the computer got passengers to their destination, safely.

This perception subtly opens the door to cost-saving notions justified on the basis of utility and safety. The matter is far more complex. There is risk in portraying this state of affairs as an industrial and an economic issue. It is such a matter but only in part.

The notion that ‘automation reduces the need for pilots’ has slowly translated into legitimation of changed (lowered) hiring standards, lowered wages and, importantly, a loss of those financially intangible but psychologically-critical factors such as professionalism and its associated sense of “the apprenticeship” when bringing new pilots along.

This process has become self-justifying and is now self-sustaining. In fact the goal of papers like this from many people who do this work is to intervene in this recursive process by answering the question about why the character of accidents is changing.

Another side of this is awareness is, the career, (and the industry itself), has become especially unattractive to young people who find they can do far better elsewhere. Captain Sullenberger spoke eloquently of this in his February 2009 presentation before Congress.

In speaking with senior executives in the business (major carrier) who regularly visit the flying schools and universities from which airline pilot candidates come, I hear that they are seeing a significant dwindling of pilot entrants. Young people are not coming into the profession.

Those visiting the schools say that the passion for aviation has been lost. They know that such passion has been taken advantage of and young people now know how corporate values degrade the profession. As a result they are going to more rewarding jobs, careers or professions to earn their living. This is not necessarily about capability and talent; it is as much about attitude as anything.

Downward pressures on regional carrier pilot wages are significant. We know that the First Officer on the Colgan Q400 was earning US$16,000/year. She was living at home with her Mom and Dad near Seattle while commuting to fly out of Newark. These circumstances have been unfolding over the last thirty years and are not the result of recent events. These circumstances and low wages are common in the commercial aviation industry.

There is another factor in the development of a professional pilot which has been lost and that is the notion of “apprenticeship”.

With regard to the Colgan accident, there was no one within this organization teaching their young First Officer how to be a professional pilot. This lack is not unique to one airline.

There was no one, including her captain, who was teaching her, for example, that texting during taxiing was unprofessional.

Should she have known it was unprofessional? Young and old are endlessly texting and talking on cell phones, while driving cars, operating trains, ships and heavy equipment. Today in our culture it is “normal”. We must ask, Wither “professionalism?”

Defined in law, the Colgan First Officer was “qualified” and passed flight tests but that is where her professional development stopped. I have deep empathy for this First Officer and all new entrants to our profession.

The changes required are not ours alone to make, and they are not all merely “technical”.

B-Schools and an MBA degree do not teach business leaders about the principles of aviation, perhaps nor should they. But those entering aviation at the executive level do not innately possess an understanding of how high-risk enterprises are made safe and they need to to be able to provide leadership in non-finance areas of an aviation operation.

What is good for shareholders and what looks good on quarterly reports often does not present a full picture. The notion of “risk”, if broached at all in such reports, is only framed in the fiscal discourse.

The nature of aviation accidents has been changing. We know that there is an increase in loss-of-control accidents. We are starting to see why this is so but the question requires a change in perspective. Automation is neither servant nor master; automation is kit.

Sorry for the length slats11- these issues beg to be discussed, perhaps in other forum threads but I wanted to echo your concerns as part of the discussion on AF447 because I believe there is a relationship.

[Organfreak]

Absolutely brilliant article, PJ2! I humbly suggest that you submit it for publication. Your political/corporate analysis is astute.

This is the true cause of this awful crash, and likely more to come.
(At last I reveal my stripes.)

[Owain Glyndwr]

I hope Owain Glyndwr can cut in and correct where i´m wrong or to add where necessary.

Franzl,

There is not a lot I can add to your remarks, but I can't resist an invitation ;)

The BEA wording is rather loose, but I think the context indicates that they are concerned with static "speed stability" rather than classical short period mode.

It is fundamental that you can change/control either speed or flight path by the use of elevator alone, but not both at the same time.

So JT's description of "pull to reduce speed, push to increase it" is fine for classical airplanes or the A330 in direct law, but it rather loses meaning when stick movement commands a flight path change. Even more so when the implied pilot's command on releasing the stick is "Hold this flight path". With the flight path being held by the FCS any pitching moments are taken care of by the automatics so the CG to aerodynamic centre moment arm isn't really a great concern for speed control. For what it's worth, the aircraft would have to be statically stable in pitch to get certification. Moreover (and I am not sure of my ground here) I think they might have had to show that it was flyable for extended periods in failed states to get EROPS clearance.

Speed stability on the A330 in normal or alternate laws is therefore a rather different animal to what we were all brought up to understand.

As I said previously, it looks as if the aircraft under normal or alternate laws would be more or less neutrally speed stable over a fair range of airspeed - say from 200 kts to 260 kts - and increasingly speed stable above that (Mach 'tuck' effects excepted - but they seem to be modest and it doesn't affect AF447 anyway). Below about 200 kts the aircraft would be increasingly speed unstable because it would be flying up the back side of the drag curve.

The problem, as I see it, is that if the FCS is trying to maintain 1g flight when the airspeed is falling it will apply NU pitch. But even though the aircraft is descending rapidly the measured 'g' (without pilot input) may not be all that far away from 1.0 so that NU command may not be all that big (I'm not specifically relating to AF447 here because there was considerable pilot input on those traces). In such a case the attitude might not change much even though the airplane was decelerating and the AoA increasing rapidly due to the increasingly negative flight path angle. I think this is what the BEA are getting at.

[llagonne66]

Right on the spot PJ2 !

What we are witnessing in the aerospace industry today with deregulation and enforcement of regulations by those that have all kind of incentives to watch the other way is also SOP in others high risk industries such as oil, nuclear power and banking.
In the end, the golden rule of neo-liberalism is always applied : privatize profits and socialize losses !

Back to the thread, the recent discussions about "stability" are much more interesting than the senseless ramblings about BEA / Airbus / AF / French State hiding the thruth from the unsuspecting public. Thanks to all for these knowledgeable inputs on that matter !

[hetfield]

Back to the thread, the recent discussions about "stability" are much more interesting than the senseless ramblings about BEA / Airbus / AF / French State hiding the thruth from the unsuspecting public.

Why should that be "senseless" ?

I'm afraid it would make sense for all mentioned parties to hide the truth or at least some aspects.

[llagonne66]

Hetfield,

Because against tremendous odds (A/C lost at night, in the middle of an ocean and in deep water), BEA / Airbus / AF / French State spent months and millions of bucks to find the wreckage. And they found it ... just for the sake of hiding the truth :ugh:

A330/340 A/C have flown more than 30 000 000 hours since their entry into service. No doubt that BEA / Airbus / AF / French State need to hide the fact that it is poorly designed and full of traps for unsuspecting pilots !

[mm43]

@A33Zab;AP engagement is inhibited when the FMGEC receives the "pitch angle protection active" information from the FCPC.Though PAP is "lost" in ALT and DIRECT Laws?

So your logic schematic is still correct for all conditions.

[gums]

Thank you, OG, for your contribution.

There's one helluva difference between speed stability and longitudinal static/dynamic stability in the FBW jets that emphasize gee compared to what many of us learned back when the Earth was still cooling.

The 'bus does not change the center of aero pressure using the control surfaces or the FBW system. The crew can change the cee gee by transferring fuel or having all the SLF's run back and forth, but the aero remains the same. Maybe the F-111. F-14 and Tornado could actually change the center of aero.

The big deal is that one can reduce the downward lift from the elevators/THS in order to gain fuel efficiency and such by moving the cee gee aft. The jet does not come anywhere close to the tiny one I flew in the dark ages of FBW. As an example, we manually transferred fuel once the deep stall phenomena was verified. This gave us a forward cee gee and supposedly help keep us outta test pilot land. Unfortunately, we would forget to re-position the fuel transfer switch back to "normal" when coming home after initially placing it in "aft fuel transfer". Hell, we were joining up and changing IFF codes and all that stuff. The procedure was not in our checklists, either. So we would have an unbelieveable aft cee gee. I only weighed about 135 - 140 pounds naked, and maybe 150 pounds with survival gear on. Our nose gear WOW would intermittently disconnect our nose wheel steering. So one day I stepped off the ladder and the jet started to tilt back on the engine exhaust nozzles!!! Crew chief and I grabbed the nose and I stepped back on the boarding ladder!!! Still laugh about that. But my point is that no jet ever built could have been flown with that combination of cee gee and center of aero pressure.

Gotta go, and some good discussion here. I'll address PJ's point paper later, maybe a separate thread.

[TTex600]

We could say it is cultural but I think of it also as a political economy which has been developing since the early 70's, sometimes loosely known as "neo-liberalism" - the notion that privatization, de-regulation, and "free enterprise" will provide "market solutions" for all problems including the ones you have just outlined.

I will counter with this.

A market solution has never been tried.

A market solution would exclude government "oversight" in all ways and safety would be dictated by the customers. In such an environment, airline X could sell tickets based entirely on price and airline Y could sell tickets on properly maintained birds - properly trained pilots - adequate fuel loads, etc.

I'm not necessarily endorsing such a solution, but it certainly has not been tried up to now.

[mm43]

Originally posted by TTex600 ...
A market solution would exclude government "oversight" in all ways and safety would be dictated by the customers. In such an environment, airline X could sell tickets based entirely on price and airline Y could sell tickets on properly maintained birds - properly trained pilots - adequate fuel loads, etc.The premiums required by the insurance industry in this X versus Y scenario would IMO work very rapidly to restoring something close to the status quo.

[jcjeant]

BEA / Airbus / AF / French State spent months and millions of bucks to find the wreckageEstimated price of all searches is 18 million Euros
A330-200 factory list price (2010) is 191.4 million dollars
Everything is relative ...
The price of research is not very high for the sake of (maybe) increase the safety of flights

[DozyWannabe]

I'm afraid it would make sense for all mentioned parties to hide the truth or at least some aspects.

Not really. The fallout of the DC-10 "Gentlemens' Agreement" proved that if you try to deal with problems surreptitiously, it *will* come back and bite you in the empennage.

Though PAP is "lost" in ALT and DIRECT Laws?

I think by "active" it means "engaged and working" rather than merely "armed and ready". This makes sense because you don't want autopilot commands muddying the waters when you're in that situation.

I only weighed about 135 - 140 pounds naked

You rode the F-16 bareback? Duuuude! ;)

A market solution has never been tried.

To all intents and purposes it has, and the result was the Great Depression.

A market solution would exclude government "oversight" in all ways and safety would be dictated by the customers. In such an environment, airline X could sell tickets based entirely on price and airline Y could sell tickets on properly maintained birds - properly trained pilots - adequate fuel loads, etc.

Except that's not how it works though. What would in all likelihood happen is that your hypothetical "Airline X" would undercut the hypothetical (safe) "Airline Y", and because of the technological and safety advances, X would get away with shaving safety margins for some time - probably long enough for Y to go out of business, with X taking over the routes and heading towards a monopoly. By the time something catastrophic happens to X, either it will have become a monopoly (meaning the choice is X or nothing), or the only remaining competing airlines will also be price-driven - meaning if the accident puts X out of business, the only remaining players are much the same.

The problem with all these modern "free-market" theories is that they don't take human capriciousness into account.

@PJ2 : :ok:

[OK465]

(b) AP engagement is inhibited in flight when CAS < VLS or CAS > (VMO/MMO or VLE/VFE).

A33Zab:

I understand what you're saying and I thank you for the info.

However, it's not what I'm seeing, and it leads me to question either the fidelity of the simulation, or the 'applicability' of the guidance in 'all' circumstances.

In the interest of quality simulation I'm not quite willing to accept either one or the other just yet. :)

[chrisN]

Dozy, I think that if the legal liability, and hence the insurance costs, are included in the “market” place for airline X, X may not be cheapest after all. This would depend upon somebody persuading the insurers of the x-type risks, and providing enough quantitative data for actuaries or assessors to put a price on it, but insurers are a conservative lot and price highly for unknown elements.

(Edited to add – In fact, when the legal costs are finally added up for Air France, I would not be at all surprised if the savings in training with no manual flying at cruise altitude, lack of UAS comprehension, poor CRM etc. are exceeded by the costs.)

[TTex600]

A market solution has never been tried.
To all intents and purposes it has, and the result was the Great Depression.

I somehow doubt that the mods want this to turn into politics. My argument was micro, not macro and we're talking about aviation not world economies.

[wozzo]

A market solution would exclude government "oversight" in all ways and safety would be dictated by the customers. In such an environment, airline X could sell tickets based entirely on price and airline Y could sell tickets on properly maintained birds - properly trained pilots - adequate fuel loads, etc.
This market solution, how is it working out for all the people who live, walk, loiter or posses land and property under the flight and potential crash paths? Will the airlines have to get individual permission from each of these people, pay life insurance for them and compensate individually for noise and other emissions? Who owns the air the airlines obviously need for their business, who "rents" it out to them, at what price, who sets the conditions?

[slats11]

The problem is that RPT air travel is so safe that most carriers ( with a few notorious exceptions) look much the same regarding safety to the average person. The inflight experience is much the same. The schedules are much the same. This has left price as a key discriminator for a large section of the market.

In this environment airlines must compete on price. The growth in LCC is evidence of this. Legacy airlines are cutting costs where they can. Using offshore cabin crew, offshoring maintenance and eroding existing terms and conditions are examples of this.

I suspect some managers are concerned about degraded pilot skills. But they are between a rock and a hard place. There is no point being safe if you are out of business. Other managers do not understand and will not listen.

And so everyone is playing the odds. Air travel is still pretty safe even with a few corners cut. The planes and the wider system are safer than before. And hopefully this will be enough. And it almost always is.

In the event of a disaster, various conventions will serve to limit liability. And the causes will be sufficiently complex that the blame and costs will be shared. That's how the risk managers and lawyers view it.

Market forces at predicated on an informed market. This is not the case here.

It would be great if the insurers sent a price signal. They likely do up to a point, but only up to a point. Insurance is most efficient with a frequent number of smal claims ( auto accidents or heart attacks). The high frequency allows accurate determination of risk. That is not the case with infrequent catastrophic claims. Insurers manage these through exclusions (acts of God, war etc) and also through reinsurance.

With airlines, crashes are rare and so insurers have difficulty determiniing the risk to apply. AF however may have now had a sufficiently bad run that the insurers will see hem as high risk.

If premiums really offset savings from corners cut, then LCC wouldn't be growing as they are.

[A33Zab]

mm43:


AP engagement is inhibited when the FMGEC receives the "pitch angle protection active" information from the FCPC.


IMO they mean: activated (in NORMAL LAW θ <-15° or θ >25/30°)
This is outside APs own Operational Conditions θ >10° and θ <22° which are also valid in ALTERNATE.

OK465:

In the interest of quality simulation I'm not quite willing to accept either one or the other just yet. http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/smile.gif

Text is from AMM, but you have reason to question this based on your sim experience.

Are you able to verify this in NORMAL LAW condition in the sim?
AP & A/THR off,
NORMAL Law (to make sure VLS available),
fly CAS<VLS-5 and then try to engage AP....?

[mm43]

A33Zab;IMO they mean: activated (in NORMAL LAW θ <-15° or θ >25/30°)
This is outside APs own Operational Conditions θ >10° and θ <22° which are also valid in ALTERNATE.Yes, I agree with that, and thanks.

I think OK465 is looking very carefully at "all" the other combinations to ensure that what is being said here actually matches the sim. Will be interesting if a difference is found.

[BWV 988]

PJ2 wrote at 20th Jul 2012 18:27

The changes required are not ours alone to make, and they are not all merely “technical”.

B-Schools and an MBA degree do not teach business leaders about the principles of aviation, perhaps nor should they. But those entering aviation at the executive level do not innately possess an understanding of how high-risk enterprises are made safe and they need to to be able to provide leadership in non-finance areas of an aviation operation.

Your comments are spot on, and relevant in medicine as well. Remember Monty Python's machine-that-goes-ping?

Monty Python - Hospital Sketch - YouTube

At least doctors and pilots should know better than relying completely on error-prone gizmos.

When executives don't understand the field they're in, it's limbo based on short-term profits. To those guys, AF447 will hopefully be an indication how the bar can't go lower wrt pilot training.

[DozyWannabe]

Estimated price of all searches is 18 million Euros
A330-200 factory list price (2010) is 191.4 million dollars
Everything is relative ...

That sounds like a large discrepancy, but what's the all-up manufacturing cost of an A330-200 (including development) per unit sold?

Dozy, I think that if the legal liability, and hence the insurance costs, are included in the “market” place for airline X

The problem is that in an entirely unregulated economy, the judiciary would be as up for sale as any corporation - hell, we even have that now! Say a crash killed 300 families and they were able to donate an average of, say, $3,000* to the legal fund - a large corporation would still be able to outspend them.

(Edited to add – In fact, when the legal costs are finally added up for Air France, I would not be at all surprised if the savings in training with no manual flying at cruise altitude, lack of UAS comprehension, poor CRM etc. are exceeded by the costs.)

True, but the peculiarity of the Continental legal system as well as the social democratic system of government means that AF and Airbus have to fight criminal as well as civil proceedings as a matter of course. In a deregulated economy, they'd be able to buy their way out of trouble.

[* - Comrade Dozy uses imperialist denomination for ease of reference... ;) ]

[jcjeant]

That sounds like a large discrepancy, but what's the all-up manufacturing cost of an A330-200 (including development) per unit sold?
I do not know and it does not matter
What I know is that Air France (and also the French government) can buying many A330 disregard of the high price .. and Airbus .. have the expected benefits as required
So the expenditure of 18 million Euros for research is a small amount of money for all concerned
Although on a purely economic point of view it is an investment without direct profitability ... this must be considered an investment that can improve safety .. and therefore can generate income in the future

[HazelNuts39]

(deleted ...)

[jcjeant]

Measures to prevent stall probably provide a better 'return on investment'.
Indeed .. and we know it was a stall thank's to the good end result of he researches

[roulishollandais]

You probably have a lot of automation in your car, but the manufacturer doesn't explain in detail how it works.

It remains your responsibility to not to drive it negligently into the trees, killing your passengers.

"To drive it negligently into the trees, killing your passengers" ?

You are crazy ? I only fly my bicycle !:ok: Sky and birds over my head, and not destroying flowers, insects, trees ! Better for pleasure, for health, for money, for safety, for ecology, for confort : turn-and-bank indicator always OK!:)

And I never found a car able to take-off reaching some speed !:p

I have always been very estonished to see my friends not understanding the automation on their car... :{and almost all former cockpit colleagues unable and not having curiosity :rolleyes: to understand the systems of their aircraft ! (French civil aviation)

[roulishollandais]

It is fashionable to analyze aviation and all events in the light of the economy. It needs to be tried, but this seems to me erroneous :

1 Aviation has NEVER been a source of profit for airlines.:}
2. But a lot of money circulates, and attracts gangsters, who use all their dishonesty up to recover.:E
3. The economy itself is now completely distorted by incompetent financers, and finance is unrepresentative of reality.:yuk:
4. The civilian and military aviation is primarily strategic, leading politics and managers to denigrate the laws of physics, and to sacrifice justice for her :suspect::cool: and sometimes AF447...

[Rockhound]

CONF iture,
Re the "prends ça" exclamations: Otelli attributes the ones at 2:11:55 and 2:11:57 to the captain, whereas the BEA attributes them to the PNF. I would think the BEA version is correct.
Otelli writes that, from 2:11:57 on, the instrument readings alternated between valid and invalid (intermittent "Non Computed Data" condition) "when the AOA increased or decreased below 41 degrees....depending on whether the copilot pulled back or relaxed his grip on the joystick".
When, at 2:12:04.3, Bonin thought they were doing a "crazy speed" and started to deploy the speed brakes, they were actually doing 90 knots. Robert, who was PF, disabused him of this idea in short order. At that moment, according to Otelli, they were just below FL300 and descending at 15300 ft/min.
At 2:12:17 and FL250, Bonin took over the controls. From 2:12:27.4 to 2:12:32.4 there was a period of confusion as to whether they were climbing or descending.
Judging by Otelli's account, the pilots seemed to be aware of their altitude at least most of the time (and certainly below FL100), although at 2:12:45 Bonin asks what the altitude is. Robert responds, "What do you mean?". No reply from Bonin. They were at or just below FL200.
Lastly, I don't know of any link to the AF447 CVR part of Otelli's book. The chapter on AF447 occupies about 1/3 of the book. The rest of the book deals with Air India Express 212 and 812, Spanair JKK 5022, Vladivostok Avia 352 (Tu-154), and Korean 804.

[PJ2]

roulishollandais;
Re, "It is fashionable to analyze aviation and all events in the light of the economy. It needs to be tried, but this seems to me erroneous :

"1 Aviation has NEVER been a source of profit for airlines.http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/badteeth.gif"

I certainly agree with that!

"2. But a lot of money circulates, and attracts gangsters, who use all their dishonesty up to recover.http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/evil.gif "

It depends upon one's definition of what and who a "gangster" is. If we're talking organized crime and money laundering, perhaps, but the influence of such activity upon industry decision-making and priorities would be minor compared to those processes in place to maintain high levels of safety. Depends upon the country. If we are talking "banksters" however, then, apropos your #3 comment, I would obviously agree.

"3. The economy itself is now completely distorted by incompetent financers, and finance is unrepresentative of reality.http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/pukey.gif"

"4. The civilian and military aviation is primarily strategic, leading politics and managers to denigrate the laws of physics, and to sacrifice justice for her http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/cwm13.gifhttp://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/cool.gif and sometimes AF447..."

Yes, agree; that's roughly the point I'm making.

Clearly my post is not entirely a Tech topic so I won't pursue it other than in the context of the original post. Thanks for your response though.

[OK465]

A33Zab & MM43:
Are you able to verify this in NORMAL LAW condition in the sim?
AP & A/THR off,
NORMAL Law (to make sure VLS available),
fly CAS<VLS-5 and then try to engage AP....?

The system functions as expected in Normal Law.

It is in ALTERNATE Law as a result of ADR disagreement, with no characteristic speed info displayed on the PFD's (SPD LIM) and at least 2 ADR's within <20 knots that the A/P pb will engage below the same VLS value checked in NORMAL Law. CAS<VLS (not displayed).

It is still possibly a sim anomaly however.

I was just curious, as were others, about this functionality as a result of the Captain's comment late in the CVR transcript. The question does not specifically address that comment of course.

That said however, the A/P would have been the last thing on my mind at that point.

[CONF iture]

P87
The reappearance of the flight directors on the PFD when two airspeeds are calculated as similar may prompt the crew to promptly engage an autopilot. However, although the magnitude of these speeds may be the same, they may be erroneous and low, and could cause the autopilot to command flight control surface movements that are incompatible with the aircraft’s actual speed.
Is it any different if it's coming from the sidestick ?

[CONF iture]

Rockhound,
Please, would you quote as it appears in the Otelli's book, the comment made by the captain some 90 minutes before the end when he's mentioning the cumulonimbus clouds ?

[CONF iture]

THS is not even mentioned only once in the all ANALYSIS chapter ...

[RR_NDB]

Hi,

How non trained pilots could do better? (http://www.pprune.org/rumours-news/489790-af-447-report-out-23.html#post7308402)

:{

[A33Zab]

It is still possibly a sim anomaly however.



Reviewing the 'AIR CARAIBES MEMO' they had the same experience as you did.
The available manuals/documentation however don't mention this behaviour.

The manuals mention the FE part of FMGEC needs only 1 valid ADR to calculate the characteristic speeds and 2 valid ADRs for the FG functions of FMGEC.

(to calculate VLS, FE needs Vs1g from PCPC which was in ALT2B)

XTRAIT DU RAPPORT DIFFUSE PAR AIR CARAÏBES ATLANTIQUE
A 22H24 et 41S, « l’AP2 » est réengagé.
---
A 22H50 et 22H53 on enregistre respectivement les alarmes « AUTO FLT FM1(2) FAULT ».
Ces alarmes résultent des « RESET » des deux « FMGEC » lesquels visent l’élimination du « SPD LIM » « RED FLAG » et la récupération des informations « VLS » sur les deux « PFD ».

[Rockhound]

CONF,
According to Otelli, at 00:44:49 the captain says:
On va pas se laisser emmerder par des cunimbs...This differs from the BEA final report transcript:
On n'a pas été emmerdé par les cunimb hein
Personally, use of the past tense in the latter doesn't make sense to me. Otelli's version seems to me more likely.
Otelli prefaces the quote with the comment that the forecast of prominent, laterally extensive but broken cunim lasting several hours seemed not to trouble the captain very much.
Just after the captain spoke, a flight attendant enters the cockpit and enquires about the temperature in the hold. Apparently she has some perishables (a ham) in her suitcase and would like to have the temperature lowered a little. Bonin agrees to do so.

[jcjeant]

CONF,
According to Otelli, at 00:44:49 the captain says:
On va pas se laisser emmerder par des cunimbs...This differs from the BEA final report transcript:
On n'a pas été emmerdé par les cunimb heinI have already posted about those famous words of the Captain Dubois
http://www.pprune.org/tech-log/489774-af-447-thread-no-9-a-10.html#post7285724
Any answers about the meteo ? :)

[CONF iture]

On n'a pas été emmerdé par les cunimb hein
Personally, use of the past tense in the latter doesn't make sense to me. Otelli's version seems to me more likely.
OK then would you pretend the BEA is 'editing' the data ... ?
The Captain Dubois' family could maybe 'question' ... Mr Otelli to know who is really editing anything ?
Who has provided data to Mr Otelli ?
Were they accurate or already edited ... ?
By whom ?
For what purpose ?

Or is the BEA really playing with the data ?

[CONF iture]

IMO it is very likely some attempts were made during the 4 minutes period to reengage an AP especially as FD commands were available at times and no one seemed to know what has to be done with the controls.
Only the constant deflection of one sidestick may have prevented the AP to engage.
But obviously the AP would not have done anything better.

[jcjeant]

Who has provided data to Mr Otelli ?AFAIK .. Mr Otelli is not a journalist .. he is a writer
Also .. if a family is suing him in court for the fact of false or misleading writing .. he can not take refuge behind the law protecting journalists' sources
But .. maybe .. his source is a journalist :)
That's all .....

[DozyWannabe]

Is it any different if it's coming from the sidestick ?

Or the yoke for that matter - remember that modern airliners have been using airspeed data as a factor in force/deflection interpretation for several decades now.

[Rockhound]

According to the blurb on the back of Erreurs de Pilotage 5, Otelli is a demonstration pilot, with 14000 hours total time, leads an aerobatic team, is an instructor in aerobatics, and has written a number of books on aviation safety.
The CVR transcript from AF447 in his book is essentially identical with that published in the BEA final report. Clearly it was leaked to him not long after the CVR was read, probably by someone within the BEA.
I presume any differences between the transcript in the book and that in the BEA report arise from different interpretations of the audio.

[jcjeant]

I presume any differences between the transcript in the book and that in the BEA report arise from different interpretations of the audio. 1 On va pas se laisser emmerder par des cunimbs (black)
2 On n'a pas été emmerdé par les cunimb hein (white)
This is not interpretable := .. it's black or white
Also in the context of this accident .. this sentence was certainly important for those who were investigating the human side (human factors group)
The trick is knowing which one of them told (write) the truth :)
In the context of the accident ... the sentence N°2 is weird .. but must be true as it's from the BEA (who was not the only official body to hear the VCR .. provided other international investigators were fluent in french :rolleyes: )
http://www.pprune.org/tech-log/489774-af-447-thread-no-9-a-10.html#post7285724
About other investigators present (International ... NTSB .. etc. ..) the final report does not say a word .. and feature no comments from them
Which probably means they are no disagreement between them and the BEA ...

[Rockhound]

I checked back to read JCJ's earlier post (#185) concerning what the captain is supposed to have said about cunims.
Otelli writes that the weather and visibility since takeoff from Rio have been excellent and continue to be so in the vicinity of Natal, the lights of which the crew can see ahead at 00:44:45. Beyond Natal, of course, is the South Atlantic.
Otelli concludes that the captain's comment on cunim must refer to the ITCZ ahead, particularly as, four minutes earlier, the captain and Bonin were discussing the outside air temperature during the crossing of the zone.

[Rockhound]

Hi JCJ,
Just read your last post.
I confess I know nothing about playback of a CVR tape. I just naively assumed that if the audio quality is not the best, different interpretations may result.
Otelli's version of what the captain said makes sense IF what he wrote earlier is correct whereas the BEA version seems out of context.
It would be interesting to find out which version is correct.

[jcjeant]

Otelli concludes that the captain's comment on cunim must refer to the ITCZ aheadAnd the sentence in the BEA report means exactly the contrary :)
The captain sentence (BEA) indicates a past event .. and that of Otelli .. an event to come :ugh:
It would be interesting to find out which version is correct.It was a bunch of specialists in the "human factors group" .. so I suppose they were enough smart ( better than Otelli and co )to outline (sort) the best from the CVR sentences ? no ?
Weird .. ?

[mm43]

The captain sentence (BEA) indicates a past event .. and that of Otelli .. an event to comeJust to recap, there was light turbulence during the climb to FL350 which was reached at 23:00 and the turbulence then gradually dies away over the next 45 minutes. So at the time these remarks were made, there had been some turb and the ride since had been smooth for the last hour.

[Zeroninesevenone]

I've been following the AF447 case from the beginning.
PPRuNe has been very valuable to get deeper understanding of what has happened.
Very knowledegable and professional people, and I wish to say thank you.

After reading the final report of BEA, mixing it with the nine or more threads of PPRunE, I still have some question marks in my head.

First of all, if I have understood correctly, if the pilots did not do anything, all this could have not happened. If so, what was the reason the pilots started to, IMHO, degenerate the situation with bad "moves". The plane was stable and weather was not really that bad.

Was there something in the displays the saw that made them to decide to make "corrective" measures? I can understand that many ECAM messages, AP/ATHR disengagement can be disturbing but usually doing nothing is a must until you understand the situation. The pilots seemed not to understand what was happening and still they started to react. Nose up? What indicator or information would warrant a pilot to do that? The only indication of trouble I have read was UAS with some detail low level "nonsense" messages.

Which leads me to the second point. It seems that the pilots (PF, PNF) did not understand that they have a UAS situation. The plane did really nothing to help them to get understand what was really the trouble (non working pitot tube) and instead sent out a load of different low level information that the pilots could not digest in that, for them "critical" situation. Now, when the situation is confusing, the last thing you need is more details. The plane "knew" what was wrong (ADR disagree -> UAS) but did not inform the pilots in a quick, clear manner. It would have been the planes job to analyze those lower level detail problems and to build up a better message to the pilots "One pitot is malfunctioning. Apply UAS/ADR disagree procedure". Now it was left to the pilots to build up that info, from all the confusion and other ECAM messages. Also the messages are quite cryptic, with lot of acronyms and ohter things that puts pilots brains in even more pressure in a situation where the brains are already overloaded. I don't understand, from the engineering point, what is the reason, if not economical, to raise the level of the information in the planes for more easier diagnosis.

Just my humble opinion.

[TTex600]

Which leads me to the second point. It seems that the pilots (PF, PNF) did not understand that they have a UAS situation. The plane did really nothing to help them to get understand what was really the trouble (non working pitot tube) and instead sent out a load of different low level information that the pilots could not digest in that, for them "critical" situation. Now, when the situation is confusing, the last thing you need is more details. The plane "knew" what was wrong (ADR disagree -> UAS) but did not inform the pilots in a quick, clear manner. It would have been the planes job to analyze those lower level detail problems and to build up a better message to the pilots "One pitot is malfunctioning. Apply UAS/ADR disagree procedure". Now it was left to the pilots to build up that info, from all the confusion and other ECAM messages. Also the messages are quite cryptic, with lot of acronyms and ohter things that puts pilots brains in even more pressure in a situation where the brains are already overloaded. I don't understand, from the engineering point, what is the reason, if not economical, to raise the level of the information in the planes for more easier diagnosis.

Just my humble opinion.

ZeroNine

You want to know why the aircraft failed to pass along information that it's logic knew? I'll say this, then duck for incoming from certain persons who take years to design something that I the pilot have seconds to deal with.

The aircraft doesn't tell everything because there would be liability in doing so. Every part of this Godforsaken industry hides behind the pilot. No matter what, the pilot is legally responsible, which leads to manufacturers making statements to the effect that pilots are expected to follow procedure and understand situation before they act. If they produce a product that an attorney could represent in court as being infallible, they would then be responsible for the fallibility of that product. It's far easier to leave all final responsibility on the shoulders of those of us who veins carry a slightly more substantial mixture of guts and ice water.

Edit: and one more thing. Pilots are also guilty of the same mindset. This business eats its young in a non discriminatory manner.

[mary meagher]

Been thinking about PJ2's analysis of the effect of reliance on automation to replace experienced pilots, which has resulted in at least two aviation disasters. AF, and Colgan. He emphasises that automation is a tool, which enables pilots with experience and judgement to fly even more safely complex aircraft accurately, further enabling air traffic to shoehorn even more aircraft safely into ever busier airspace.

Beancounters love it because new pilots can now fly hands off and brains disengaged, while the automation delivers the cargo/SL or otherwise, safely to the destination on time. Most of the time.

Except that even the finest designs are surprised by events as simple as ice in the pitot tubes, and the responsible guys with the four stripes are suddenly asking "What is it doing now!" and the FO without experience in a panic does exactly the wrong thing. And the design of the sidesticks ensures that the others don't realise he is pulling when he ought to be pushing....meanwhile all the bells, whoops, whistles, overload and distract from the simple and most important information; this aircraft is STALLED.
TOGA is not going to help.

I am sure that pilots have tried to set up this situation in a simulator; how real can it be? when you crash a simulator (I've done that, at Cranebank) the lights go out, they open the door and tell you sorry, chaps, you're dead.
How can new recruits get real stick time? how can hours - thousands of hours sitting in the pointy end letting the computer fly the plane, add up to experience? - Sullenberger was a gliding instructor, and always was thinking ahead in flying his plane, so when the geese were cooked, he was calm and ready and did the right thing, with only seconds to make the decisions. How do we make sure that future professional pilots have this quality?

[A33Zab]

The plane "knew" what was wrong (ADR disagree -> UAS) but did not inform the pilots in a quick, clear manner. It would have been the planes job to analyze those lower level detail problems and to build up a better message to the pilots "One pitot is malfunctioning. Apply UAS/ADR disagree procedure". Now it was left to the pilots to build up that info, from all the confusion and other ECAM messages. Also the messages are quite cryptic, with lot of acronyms and ohter things that puts pilots brains in even more pressure in a situation where the brains are already overloaded. I don't understand, from the engineering point, what is the reason, if not economical, to raise the level of the information in the planes for more easier diagnosis.



1// It was not only one pitot, it were all 3 and not at the same value and duration. If it had been only 1 this one was isolated and that would have been clear to both A/C as pilots.

2// Due to the difference in both values as in duration the automation could not set the ADR disagree message in the initial phase.

3// The messages are not cryptic (at least NOT to airbii insiders) they are brief and if any crew action is required it will be displayed in a cyan color and idented to distinct it from the message itself.

f.i. there was no ECAM action to select RH PFD to ADR 3, with this action they extended the duration of unreliable airspeed indication on his display.

There is no need to make an epistle with detailed information were you will forget the first part before you ever read the last part, one can select (after regaining control!) the status page for detailed information and affected (inop) systems.

@CONF iture:

But obviously the AP would not have done anything better.

That will be correct once it was already in stall condition, but the AP would have prevented itself to 'PULL' into stall.

[PJ2]

Every part of this Godforsaken industry hides behind the pilot. No matter what, the pilot is legally responsible, which leads to manufacturers making statements to the effect that pilots are expected to follow procedure and understand situation before they act.
We need to think about that statement.

First, as pilots we all know that the captain is legally responsible; that is ancient maritime and aviation law.

That said, I think it is entirely reasonable that manufacturers expect pilots to follow procedures and understand the situation before they act. That is what we do. However I believe what you may be saying is that the manufacturer may possibly hand the pilot a situation which is completely confusing for which there is no training, no information in the FCTM, poor indications of what is wrong or no industry experience with the abnormal and the crew has to make up a response. I don't think that is the case here. The failure and the correct response was well understood by June 2009, the industry had had many such events and information was out as early as 2006 on how to treat the failure when the aircraft is not at immediate risk. The question within this context is, Why didn't this crew know this and why did they respond the way they did prior to the stall?, (all bets are off once the airplane was stalled).

The notion of the "organizational accident" has been around since Perrow's work in 1984. I'm not exactly sure what is meant by the term, "industry", but despite what some corporate lawyers may argue and want because we're seen as their 50,000A fuse, many organizations in this industry cannot duck responsibility for design, process, structure, priorities etc., any more. Pick up Diane Vaughn's, "The Challenger Launch Decision" or anything by Chick Perrow or Sidney Dekker. From airline managements to airframers to systems engineers, the legal net is cast broadly in many countries though there are notable exceptions.

There are very few abnormals or even emergencies which require you, as the pilot, to deal with "in seconds". The rejected takeoff, an engine fire/failure/severe damage, rapid depressurization/emergency descent, runaway stab, aircraft stall indications, TCAS & EGPWS warnings, (by design, both require moderate, not extreme responses), loss of airspeed/altitude information at/right after takeoff and perhaps some go-arounds, (from CATII/III) all require immediate and accurate responses. Right after these, smoke of unknown origin requires an urgent but measured response using checklist/QRH. Hydraulic, electrical, landing gear and flight controls require attention but not as rapidly as the two former emergencies. Then there are numerous abnormalities associated with aircraft systems which are type-specific and may, though likely not, require an immediate response.

I wrote in June 2009 that the loss of airspeed information at cruise altitude is not an emergency and does not require immediate action. What is required immediately is calm, then a collection of thoughts to ensure cockpit discipline which means launching into standard procedures. Ensure control and stability of the flight path and navigation, call for the drill or checklist while taking the radios (if necessary) and as per training, confirm any non-reversible items before actioning them.

Nowhere is there a call for the actions that took place here. If the crew does not maintain the standard required cockpit discipline, there is no system or aircraft design that can overcome the unpredictable outcomes that may, and here did, follow.

The business is not going to hell in a handbasket, but there are indications that in specific quarters, all is not well. This accident among a few others, is in my view an indication of that fact, especially when thirty-odd other crews dealt to varying degrees of perception and action with a similar loss without major incident.

My views on automation and the industry are expressed but I am an enthusiastic supporter of automation providing we don't forget who we are or permit others to define who we are when in the cockpit and flying their airplanes. Skills, knowledge, readiness and discipline are our responsibility alone and where we deem them threatened we have to speak up, just as we are doing here, at conferences and in management meetings. Hopefully we're paying attention to our safety reporting system and FOQA data as well.

[jcjeant]

The failure and the correct response was well understood by June 2009, the industry had had many such events and information was out as early as 2006 on how to treat the failure when the aircraft is not at immediate riskIndeed ...
But some reports readings indicate the contrary ..
Why didn't this crew know this and why did they respond the way they did prior to the stallHow many (in the UAS incidents before AF447) crew applied the correct procedure in force at date ?

[TTex600]

Skills, knowledge, readiness and discipline are our responsibility alone and where we deem them threatened we have to speak up, just as we are doing here, at conferences and in management meetings.

PJ, you are informed, articulate, well spoken, etc, but the quoted statement is part of the problem. It's true, but that doesn't matter. The pilot being "responsible" does nothing to bring back 228 dead people. The pilot being "responsible" does nothing when he/she is responsible for a system that has outgrown his capability. Allowing the pilot to take "responsibility" for failures in training, checking, regulation, oversight, design and design philosophy will accomplish nothing in our quest to remain safe.

I suspect you are either a senior Check Pilot or other instructor for a legacy carrier. Come down a bit lower in the ranks and you might see what I see - new hire pilots that go straight from the right seat of a B1900 to the right seat of a CRJ to the right seat of an A321. I know of exactly that background pilot today flying left seat of international ops A320's. They've never had an hour of instruction in high altitude, high speed ops. They have somewhere around 100 hours flying pitch and power with no Flight Director. I can go on, but I'll sum it up with this. As previously posted, sometimes you don't know what you don't know. I believe a significant portion of the younger generation is in exactly that state. They don't know what they don't know, and very few airlines are willing to spend the money to inform them.

So it's nice that they are "responsible" but we all better hope they have some luck to go along with it.

[Lyman]

Hi Tex...

"Come down a bit lower in the ranks and you might see what I see - new hire pilots that go straight from the right seat of a B1900 to the right seat of a CRJ to the right seat of an A321."

That is striking re: flight time, but erm, where does command experience come from?

[PJ2]

but the quoted statement is part of the problem.
I realize that after I re-read it. I wasn't clear on my meaning but I touch on the matter in my response.

Clearly we don't run the show at an airline and are at the beck-and-call of our airline's training program, scripting and the regulator's requirements. If those requirements or training regimes don't cover sufficient territory to ensure the kinds of skills that were missing in this accident then the training program, the airline and the regulator need to be examined as to why. My point was, a loss of airspeed information should not have "outgrown a pilot's capability" - it's not unknown territory. Now we both know that training regimes and sim time are jammed to the hilt already, so covering everything is not possible. I don't have the answer to that.
I suspect you are either a senior Check Pilot or other instructor for a legacy carrier. Come down a bit lower in the ranks and you might see what I see - new hire pilots that go straight from the right seat of a B1900 to the right seat of a CRJ to the right seat of an A321
As my public profile says, I'm now retired, so yes, I am "senior" http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/infopop/icons/icon7.gif . I instructed in line indoctrination, (A320) but I was never management and never a check pilot. I worked in our pilots' union for a number of years. I was down in the ranks as an ordinary line pilot from Day One in 1973 to the last in 2007. I am not an engineer nor do I have such a background but I like to learn as much as I can from those who are and who do that wonderful work. I am a flight data analysis specialist so I see many of the things under discussion.

I find this profession and industry deeply fascinating and love discussing it, especially human factors and flight safety work. In terms of A vs B or whatever, I have no favourite types but pushed, it would be the L1011-500.

That's the only "place" all this comes from and here on PPRuNe is about the only online site where a good dialogue can get going and be sustained with those from whom one can really learn stuff.

I don't mean to appear to be in a level which I should "come down from" to see the ranks - that's where I was for 35 years. But I have seen a lot of sides of this business and while I don't mean to push it, I think as broad a view of what we do/did for a living is important and valuable and I sincerely believe that such an attitude is good for those getting into this industry, and so is constant reading and learning. That's what defines a professional, I think.
I know of exactly that background pilot today flying left seat of international ops A320's. They've never had an hour of instruction in high altitude, high speed ops. They have somewhere around 100 hours flying pitch and power with no Flight Director. I can go on, but I'll sum it up with this. As previously posted, sometimes you don't know what you don't know. I believe a significant portion of the younger generation is in exactly that state. They don't know what they don't know, and very few airlines are willing to spend the money to inform them.
I watched how priorities, knowledge and skills changed over the years too. We're on precisely the same page.

[bubbers44]

Mary, you are absolutely right. Soon and even to a degree now experienced pilots are going away with retirements. Some of the new people have not learned hand flying as in the past. AF proved it and we just have to wait a while for the next one.

If the autopilot failed it used to be a non event in the past, now it is an event. We probably will only get entry level pilots now but at least if they increase the FO requirements as they plan or did maybe that will help a little. Flying automatic airplanes doesn't make you an experienced pilot, just a monitor of an autopilot.

[RR_NDB]

In terms of A vs B or whatever, I have no favourite types but pushed, it would be the L1011-500. (http://www.pprune.org/tech-log/489774-af-447-thread-no-9-a-34.html#post7311564)

:ok:

Despite RB211 delays, etc.

[CONF iture]

That will be correct once it was already in stall condition, but the AP would have prevented itself to 'PULL' into stall.
No Sir, the AP would have done exactly what the PF actually did : Follow the FD to 'PULL' the aircraft into stall.

[Zeroninesevenone]

TTex600:

You want to know why the aircraft failed to pass along information that it's logic knew? I'll say this, then duck for incoming from certain persons who take years to design something that I the pilot have seconds to deal with.

Thanks.

The aircraft doesn't tell everything because there would be liability in doing so.

I was expecting this, but as liability goes, it is very volatile matter. Incredible to think that better diagnosis by the plane would get the manufacturers even in deeper trouble.

Every part of this Godforsaken industry hides behind the pilot. No matter what, the pilot is legally responsible, which leads to manufacturers making statements to the effect that pilots are expected to follow procedure and understand situation before they act.

What I have read, I cannot but agree.

[Zeroninesevenone]

1// It was not only one pitot, it were all 3 and not at the same value and duration. If it had been only 1 this one was isolated and that would have been clear to both A/C as pilots.

You are right. My mistake after remembering the page 96 of the final report.

2// Due to the difference in both values as in duration the automation could not set the ADR disagree message in the initial phase.

Agreed. But in 40 seconds period it could have, generating a better diagnostics. As the final report says on page 176: "the ECAM displays no information that is likely to point to a speed indication problem". But the AP disconnected exactly because of this.." .. "It should be noted that the reconfiguration to alternate law occurred because of the triggering of specific monitoring that is designed to react to events like icing of several Pitot probes, However, no explicit indication that could allow a rapid and accurate disgnosis was presented to the crew".
The plane knew something it did not "bother" to say.

3// The messages are not cryptic (at least NOT to airbii insiders) they are brief and if any crew action is required it will be displayed in a cyan color and idented to distinct it from the message itself.

I am sure they are quite familiar to AB pilots. Still I think that the briefness of the messages can add to the congnitive stress situations more than ease it. Many times acronyms can speed up reading, but under stress it can be deteriorating.

"Between 2 h 10 min 18 and 2 h 10 min 25, the PNF read out the ECAM messages in a disorganized manner"

Surely there could be a better way to get the messages out and understood.


f.i. there was no ECAM action to select RH PFD to ADR 3, with this action they extended the duration of unreliable airspeed indication on his display.

Maybe a step to identify the problem by exclusion. They had the info at that point, at 2.11.06.


Still I cannot help to think that there was something, in the displays, indicators or anywhere that made quite experienced pilots to start moving the plane before understanding the situation.
And even when it seems they started to get the understanding, they did not apply anymore.

Thanks!

[PJ2]

Still I think that the briefness of the messages can add to the congnitive stress situations more than ease it. Many times acronyms can speed up reading, but under stress it can be deteriorating.

"Between 2 h 10 min 18 and 2 h 10 min 25, the PNF read out the ECAM messages in a disorganized manner"

Surely there could be a better way to get the messages out and understood.
Under stress perceptions do change but that's what training, training, training, (and continuous study and learning as part of one's profession) is for. Such responses cannot be eliminated but they can be reduced by familiarity.

The QANTAS A380 event shows how complex the ECAM can be but that system is extremely well designed and works providing it is followed to completion.

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 popular notion of "startle effect" has some place in this discussion because responses are always going to be influenced by the immediacy of an event. However, these trained responses are absolutely standard and what recurrent simulator sessions are all about and are intended in part to reduce the effects of surprise.

You might google "CRM" as that is the way cockpit communications are conducted when an emergency/abnormality occurs, ensuring a) all crew members are aware of the problem, b) everyone is prepared for what's next and c) awareness is followed by a plan of action and resolution of the problem. The process is about "what, not who", so anyone who senses/sees a problem speaks up and the matter must be resolved to everyone's satisfaction. It isn't a democracy, it is a way of communicating information so that everyone is aware. The captain always has the final word.
Still I cannot help to think that there was something, in the displays, indicators or anywhere that made quite experienced pilots to start moving the plane before understanding the situation.
The barometric altitude reduced slightly and it has been theorized that this was a reason for the immediate, strong pull-up by the PF.

While that may be an explanation for the instant pull on the stick, it does not explain the continued pitch-up and climb in which SOPs and cockpit discipline were entirely absent. As I have said many times, even given the pull to stop what may have been perceived as a descent, the airplane settled down quickly and if the PF had done nothing but maintained pitch and power while calling for ECAM Actions while ensuring stable flight, (and 10 to 12deg pitch is NOT stable flight at cruise altitudes!), we wouldnt' be discussing an accident here.

[Lonewolf_50]

For Zeroninesevenone:

Tex's response makes sense to me, but I'd like to restate something that has been a point of discussion over the past three years: The aircraft senses AoA, but does not display it on the instrument panel. IIRC, it takes six or seven key strokes (based on what I've been told, I've never done this in an A330, so I don't know) to get to the page that displays AoA.

Would an AoA gage, or an AoA reading imbedded in a corner of the display have given the crew a better sense of what they were looking at, what their wing was doing, or make the stall warning alarm more compelling to them?

We don't know. Based on what is available to analyze, the scan breakdown (possibly due to training? Possibly due to over reliance on the bird? Possibly due to few reps in sims? We don't know) was a critical part of the upset, and a CRM breakdown contributed no small amount.

We don't know what we don't know,

I understand why some do not think an AoA gage is needed, in the idea of a pound of prevention being worth a pound of cure.

You typically take steps to NOT fly near the edge of stall, as a matter of policy, good airmanship, and for the sake of your passengers.

That doesn't change the fact that the aircraft has AoA probes, you fly the wing, and if you don't know what your aircraft is doing you can make a fundemantal mistake.

AoA is a critical metric that tells you whether or not you are flying, or falling.

I conrfess, I learned to fly on small aircraft with no AoA gage.

Varga 2150a Kachina Aircraft history performance and specifications (http://www.pilotfriend.com/aircraft%20performance/varga.htm)

I also knew well enough not to stall, but that little plane had a very easy to recognize buffet. Also, where I flew that little plane, icing up the pitot tubes wasn't an issue: I didn't fly in bad weather.

I later taught flying in the Navy in a trainer that had AoA gage. My cockpit awareness, once I learned how to use it, increased significantly.

What I had to do versus what professional pilots, who fly pax each day, have to do differs considerably. I realize the arguments against, but the data is already being fed into the cockpit.

How about making it available? Yes, 99.99 percent of the time, you don't need it. Upon that 0.01% occurrence, it might help save your chili.

[Lyman]

My friend John flew the A320 for ten years before he flew the T7. He loved the Bus, and he was in Normal Law his entire ten years, the aircraft did not even hiccup, not once. I asked him about 447, he allowed that he felt for the crew, saying they got in over their head, and weren't able to find their way out.

Now John is a premier pilot, respected by all, and I listen to him. I asked what he thought his chances would be had he been flying the Sister, 330, that fateful night. He said: "Bill, not good. We get complacent, skills deteriorate, and I could not say I would do better. I like to think I would, but there was a great deal going on for those guys."

I venture to say that training is important, even paramount, but there are other things that work against success when confronted with the dicey realities of life.

Staying cool under pressure comes to mind, and having the ability to clear one's mind in the face of real danger is critical. As the possibility of danger retreats into the land of near impossibility, there, there be dragons.

Since teaching flying has deteriorated into the state it is in, and standards are almost non existent re skill, why not start looking for the psychologically prepared candidate first and foremost? The other boxes have been checked.....

Courage? Grace, under pressure.

[mm43]

Between 2 h 10 min 18 and 2 h 10 min 25, the PNF read out the ECAM messages in a disorganized mannerThat is a critical statement from the BEA, but somehow they have decided that what the PNF conveyed by speech to the PF in respect of the ECAM messages had no bearing on the conduct of the flight. That could be right, but in the circumstances, how those messages were conveyed is important in trying to understand their reception by the PF.

The "eagles" will be circling over that omission.

[OK465]

I think the report alludes to the less than optimum task load for the PNF, to the point of being difficult and frustrating to function as a dedicated, ECAM actions deciphering PNF, when you're trying to get your buddy to push the nose down.

[mm43]

So you suspect that the disorganized relay of the ECAM messages was due to the PNF's other preoccupation - keeping an eye on the PF. Strikes me that it may have been useful to know just what was said and when, and if the PF ever acknowledged any of it.

[OK465]

It's like the FD thing, educated conjecture on the surface, but certainly ringing true in the context of what goes on in crewed aircraft when the PNF's confidence level is impacted.

When I flew as an instructor during type rating training in the aircraft, it was also my job to provide all the necessary support to the trainee that he could expect to receive from a dedicated, disciplined first officer.

As the instructor, however, I was a terrible co-pilot when I could see a potential compromise of aircraft control.

[PJ2]

So you suspect that the disorganized relay of the ECAM messages was due to the PNF's other preoccupation - keeping an eye on the PF.
Yes, that certainly makes sense to me. The PNF was left without leadership but knew something had to be done regarding the ECAM and so tried to do his job but the PF had already launched on his own course of action which left the PNF in a position of not knowing how the PF was receiving the communication. The effort would be halting and interrupted by what the PF was doing with the airplane, leaving the PNF in the lurch about how, where and when to pick up the ECAM discipline and get the operation on the proper track. He had about 40 seconds to do so before the more serious problems occurred and there was no turning back after that point in terms of SOPs.

The appropriate intervention by the PNF in the face of such non-standard actions on the part of the PF would be to hold his own Takeover Priority button down longer than 30 to 40 seconds, (forgotten exactly how long) which locks out the right sidestick in order to fly the airplane uninterrupted and maintain stable flight. Surely some sense of how unstable the airplane was going to get must have entered the PNF's mind.

The PNF then becomes the PF so he could recover the airplane. Once things had calmed down he and the captain could settle the disagreement, but he likely didn't know where it was going until it was too late.

[mm43]

OK465, PJ2;

Thanks to both of you for your feedback.
Surely some sense of how unstable the airplane was going to get must have entered the PNF's mind.Demonstrated by the PNF's desire to get the Captain back, and yet apparently too timid to be assertive and take control.

The BEA's HF group must have reviewed the missing part of the CVR we are discussing and considered the relevance of the exchange, or lack of, and could draw nothing of significance from it. I am left wondering if others would.

No doubt it will be "picked over" further down the track.

[gums]

No doubt the questionable CRM is critical to this accident. Then there's a FBW system that could be improved, but that comes later in the post.

I was struck by the "brief" briefing when the aircraft commander left for a break. I heard no clear assignment of who was really in charge and who was simply flying at the time. Could be an AF standard procedure and such, I don't know. But I would prefer to have the duties and such clearly briefed.

I also heard/read on the CVR transcript the PNF say something to the effect that he had three indications of a climb and advise the PF to stop climbing. Did I get that wrong?

As most here know, I am disappointed in the lack of AoA inputs to the system when airspeed is unreliable. I shall not debate the issue of an AoA display any longer if the rank and file of the transport pilots here can't handle it or don't want it or don't think it would have helped.

OTOH, a FBW system advertising all the "protections" should certainly rank AoA very high. Airspeed inputs play a large role on the "gains" ( control surface deflections to achieve the commanded Nz or roll rate), but body rates are there by default and help a lot.

If the system designers do not use AoA sensor inputs ( cones or vanes) once speed is deemed unreliable, then why not use the obvious AoA available from the inertial system and attitude reference ( derived from inertial or a separate gyro)?

Subtract inertial flight path vector from pitch attitude and you get AoA - voila!. Then use that for stall warning, but mainly to provide the "protections" the drivers are expecting. Of all the "protections", the two that seem to be paramount are total Nz and AoA. The others in the myriad of laws/ reversions seem nice, but not as critical to basic aircraft control.

From the crew reactions, including the aircraft commander's, I cannot help but think they thot that the AoA "protections" were still in effect. "You can't stall this airplane".

that's all I'll say for now, and may comment about corporate mentality and such later.

[bubbers44]

Surely some sense of how unstable the airplane was going to get must have entered the PNF's mind.

Demonstrated by the PNF's desire to get the Captain back, and yet apparently too timid to be assertive and take control.

The BEA's HF group must have reviewed the missing part of the CVR we are discussing and considered the relevance of the exchange, or lack of, and could draw nothing of significance from it. I am left wondering if others would.

No doubt it will be "picked over" further down the track.



This is very hard to understand. He knew the PF was out of control but elected to call the captain back instead of assuming control. When the captain got back to the cockpit it was too late.

[Machinbird]

This is very hard to understand. He knew the PF was out of control but elected to call the captain back instead of assuming control. When the captain got back to the cockpit it was too late.

IMO, PM (Robert) was still suffering some effects of sleep inertia and he knew it. He just didn't trust himself. He had been awakened only a few minutes before. If he had been fully alert, it might well have been different.:suspect:

[scrubba]

Displaying alpha is only truly useful when the applicable limits are also displayed. Stall alpha at altitude is much less than at sea level, best seen by observing the slow march of the "feet" (low and high speed buffet boundaries) towards each other as you climb.

The MD 11 (and the B717) displayed a useful alpha indication by virtue of the permanent display of PLIs (pitch limit indicators) on the PFD. At all times during flight, the pilots had a clear indication of how much alpha was available - I say alpha rather than pitch, because the PLIs tended to 'float away' from the pitch attitude at low level more so than at high level. That came about for two reasons: first, the difference in the alpha envelope and, second, reflecting the difference in dynamic predictions and steady state alpha with altitude.

I can no longer remember whether there were circumstances such that the PLIs may have been inaccurate, although clearly it is possible. Certainly it would be affected by the altitude (static) input, but I don't think it was influenced by the speed (pitot) input. :ok:

But to use it, you had to look at the PFD and see the attitude - something that unfortunately seems to have disappeared from the skill set of our younger pilots, to be replaced by "magenta fixation" - whether it is the FD or the track display! :ugh: :ugh: :ugh:

[slats11]

I was struck by the "brief" briefing when the aircraft commander left for a break. I heard no clear assignment of who was really in charge and who was simply flying at the time. Could be an AF standard procedure and such, I don't know. But I would prefer to have the duties and such clearly briefed.

Thanks Gums. I had wondered about that before. A 40 second handover (between PNF entering and Captain leaving) seemed extraordinarily brief. Especially in view of weather and recent discussion about max altitude.

I am also curious about this extract from the CVR
0 h 58 min 07
Captain Try maybe to sleep twenty minutes when he comes back or before if you want
PF Yeah ok that’s kind, for the moment I don’t feel like it but if I do feel like it yeah
Is Dubois really saying he was happy for PF to have a doze while Dubois was having his rest period? Surely I am misunderstanding this.

[slats11]

IMO, PM (Robert) was still suffering some effects of sleep inertia and he knew it. He just didn't trust himself. He had been awakened only a few minutes before. If he had been fully alert, it might well have been different.

He had left the deck just 10 or so minutes earlier. Barely time to lie down. Let alone get into the deeper stages of sleep associated with sleep inertia.

[BOAC]

slats - you are confusing PM with the Captain?

While 'sleep inertia' (ie 'waking up') is a known event, I would wager that adrenalin would be a great stimulant.

[slats11]

Sorry BOAC. You are right.

Robert claimed he had not really slept well (his words were "so so"), and so was unlikely to be suffering sleep inertia.Even if he had been, he should have been coming good 15 minutes later.

The Captain had only been absent for 10 or so minutes, and so sleep inertia was unlikely the explanation for his actions when he returned.

[mm43]

bubbers44;This is very hard to understand. He knew the PF was out of control but elected to call the captain back instead of assuming control. When the captain got back to the cockpit it was too late. Poor CRM? I don't doubt for a moment. The real question is why a relatively simple loss of air data lead to such a monumental "cock up".

Is the "startle factor" excuse a cop out for poor training endemic throughout the airline, or is this event a "one out of the box" horror story? :\ The average soul could be forgiven for believing it is the latter.

Strange as it may seem, I have a suspicion that the same event could have happened in a similar fashion to more than 10% of rostered crews, but the odds have luckily worked against it happening.

The industry deserves better than a lottery style "chance" draw.

[rudderrudderrat]

Hi mm43,
Is the "startle factor" excuse a cop out for poor training endemic throughout the airline, or is this event a "one out of the box" horror story?
I think the "startle factor" is something we need to address. Normally all training is pre-briefed, so when the event happens in the simulator, there is no "surprise".

Please see the startle effect mentioned in Incident: Air France A343 near Guadeloupe on Jul 22nd 2011, rapid climb and approach to stall in upset (http://avherald.com/h?article=44280b2a):
"The flight data recorder revealed that the pilot monitoring pressed the autopilot disconnect button, no aural alert sounded, and pulled the side stick about 75% of its travel back for about 6 seconds. The aircraft subsequently rolled right and left indicative that the pilot not flying was not aware of his actions....The pitch attitude in the meantime increased from 3 to 9 degrees in 5 seconds, .... The crew reported later they did not hear the altitude alerter that sounds upon deviating 200 feet from the assigned altitude, .... the pitch angle reached 12 degrees nose up, the mach decreases.... the aircraft still climbs, the vertical speed increases through 5700 feet per minute, the crew does not notice the excessive climb rate, engine N1 is at 100%, the pilot flying switches his navigation display to a range of 160nm."

Does it sound very similar?
In the future, will we be bursting paper bags or firing starting pistols in the sim to produce the "startle factor"?

[Linktrained]

When "new to type" a briefing by an " Uncle" type trainer on the sim may be helpful. (A " Talk around the Circuit.") A Check ride might be better with a "harder" personality... Even the same person with hat turned around can create the shock of the unexpected, the " Startle factor"which may happen, even when not sitting on the edge of ones seat.

I assume that is some way to indicate to one or the other do the " Pilot Dropped Dead Drill"

AF343's pilots might have benefited from noticing that the hands of "my old sensitive altimeter" were now "showing the wrong time"!

[BOAC]

In the future, will we be bursting paper bags or firing starting pistols in the sim to produce the "startle factor"? - back to my 'Zut Alors' boxing glove in the panel?

[OK465]

The only way you're going to get the 'startle factor' in a simulator is to simulate being startled.

(One possible exception to this would be the real world sim motion base system going out of control. This has occurred. It is of limited operational training value however. :eek:)

[Lyman]

An alert pilot is not startled, surprised maybe, but not 'startled'.

However, it makes no difference the circumstances of cognition: if a pilot is confronted with a situation he/she has never experienced, the foundation for recovery is in a part of the brain that is not wired for a solution. I do not include simulation as training...

This is the foundation of the negligence exhibited by Airbus! And Air France.

UAS cannot be merely discussed, and passed along to pilots who have not flown it.

[rgbrock1]

As a non-aviator I would like to offer a real-world scenario, which I myself experienced in the hope that, perhaps, the so called 'startle factor' can be more readily appreciated.

25 Oct 1983. I was an infantryman stationed at Hunter Army Airfield near Savannah, Georgia with the 1st Ranger Battalion. (Now the 1st Ranger Bn 75 Infantry Regiment) Leading up to this date, Ronald Reagan was whining on about some unholy airstrip being constructed by Cubans, Russians and assorted other "bad guys" from Eastern Europe on the Caribbean island of Grenada. (He neglected to tell anyone that the airstrip was designed and supported by the Brits.)

Anyway, on 25 Oct 1983 the 1st Ranger Bn. embarked on C-130 and C-141 aircraft for an unannounced and most unwelcome trip down to the Caribbean. Intelligence at the time indicated that the airstrip would not be defended and the aircraft we were on could simply land on the airfield (Point Salines, Grenada) and we Rangers would simply disembark and take the airfield. However, the Cuban defenders decided to welcome us to the airstrip via small arms and anti-aircraft fire. On approach to the airfield, all our aircraft began receiving this most unexpected ground fire. The PF of our aircraft did an abrupt pull back on the stick and got our aircraft out of harms way. Even as we were hearing the pings of rounds on the fuselage.

Although as Rangers we had trained extensively for combat (train as you fight) this was a most "startling" turn of events. Which caused us to discard our planned method of ingress (landing on the airstrip) and opt for rigging our chutes and jumping from 500' onto the airstrip environs.

However, and this is the point I'm trying to impart here, there were several Rangers in my company who, after being "startled" by the ground fire, refused to jump out of the aircraft. This in the face of all the multi-hours of training we had done over the course of time. They simply sat down and refused to jump. (Well, at least until the jumpmaster kicked their collective asses out the back of the plane!) Basically, these couple of soldiers froze: training be damned. Had we landed on the airstrip as originally planned I'm quite certain they would have disembarked without being forced to.

In essence: they were "startled" into inaction. (Scared ****less as well perhaps.)

I see correlations, somewhat, between the above and the inaction, almost catatonic state, exhibited by the PF of AF447.
Perhaps this correlation is not appropriate and I'm sure I'll be called out if it is. But, me thinks it is indeed appropriate.

[OK465]

I do not include simulation as training...

A bit harsh and patently incorrect. :)

Having trained pilots in an all aircraft program, and a combination aircraft and simulation program, there was no doubt which program provided the best preparation for ALL aspects of operating the aircraft.

[Lyman]

Ok465

Perhaps some explanation. Just as Stalls must be experienced to familiarize the student with the feel of the a/c, so too must the a/c response to partial or no panel, and loss of various instrumentation be experienced.

I did Not mean to marginalize the crucial contribution of sim experience. Some AB initio must include actual flight in these domains.

Aren't we talking about lack of experiential hand flight? Try to teach a child to ride the bicycle with a sim. Never having experienced the actuals, to learn muscle memory, an adult with a PhD in Bicycle riding acquired in a simulator will not get how to ride.

Two critical cues needed to suss STALL in the A330 Are Buffet and Nose drop. Are these included in the type rating? In the aircraft?

If only to experience the docility of UAS in the air, this must be done on the natch. One cannot rue the loss of manual flight experience, and also say it is not crucial to experience it in abnormals?

If sim UAS is acceptable for the rating, perhaps an AoA gauge, Approach to STALL at altitude, and some other minimum considerations should be added to the platform?

[PJ2]

Lyman;

There's "startled", "surprised" and then being merely spring-loaded.

I can appreciate and even understand being startled over an engine failure, (loud bang, big yaw swing, vibration, bevy of cockpit warnings), but really...full-blown "negligence" when the airplane had not suffered a catastrophic engine or structural failure and was in, and could have remained in controlled flight but for its crews' actions? I think some perspective is in order.

rgbrock, good story. I can appreciate your example because being shot at has a clearly-defined possibility.

Honestly though?...I think perhaps a connection between refusing to leave the airplane when bullets await one outside, and being unable to respond as per training when faced with an aircraft abnormality because one is "startled", is a bit of a stretch.

Consider the QANTAS A380 crew, their A330 crew, their B747 crew; the QATAR Airways A310 crew, the BOAC B747 crew that lost all engines - Startled, scared, wide-eyed, shaking a bit...yes. But completely unable to function rationally and as per training and experience? No, quite the opposite.

"Startled" is an invented, psychobabble notion created by non-pilots/non-aviation people in an industry that has been dealing with transport emergencies and abnormals and improving on checklist design, system design and crew performance for same, for over fifty years. Why suddenly does the notion of being "startled" in an airliner cockpit have the currency that it does instead of being examined for what it is actually saying?

Is the trend towards relatively low cockpit experience with commensurate reducing skill standards in combination with highly-automated aircraft technologies where a pilot can now be overwhelmed by anything just beyond training and experience, finding new expressions in terms like "startled"?

Pulling the stick back and achieving such pitch attitudes because someone was "startled"?

What should have startled, no, scared this crew into action was getting to such a pitch attitude in the first place.

If "startled" is the new metric when examining human factors in aircraft accidents then there are some serious questions to be asked of those processes upstream from putting crews into transport cockpits who can handle the profession and the job.

[Lyman]

The landscape of the cognitive brain can get real empty when startled. If the pathways to a solution are blocked by both lack of thinking, and no muscle memory, if only for a few seconds, the pilot can step into the unknown and unadvisable, never to regain a starting point.

Surprise should not be fatal in and of itself. If the brain is engaged in activity that is related to the context of the environment, he is in the game. This accident is full of overstimulation post event. Without the presence of mind and the muscle memory, bad things happened. The muscle memory this pilot exhibited started out arguably on the right track, but degraded evidently into some sort of rigid 'affirmation response'.

[PJ2]

Yes, understand what you're saying and agree on how it works.

Let us compare a concert pianist, who's muscle memory is equisitely nuanced and, with extremely rare exceptions, not subject to lapse regardless of "surprise".

While not in the same class of training, (it's neither possible nor necessary) as a concert pianist, it is in the same category.

I do not agree and do not grant that minds and muscles go blank in a manner that is, as in the case of pianists, other than extremely rare. While all is not amenable to rational analysis or thought, the probability that a transport crew is going to lose the picture at the first sign of abnormality, is not a basis for explanation. There are too many counter-examples.

The one thing I think is reasonable to accept is, there is no training in actually dealing with surprise, fright, panic etc. I have in the past expressed two reasons for this: Training-training-training and SOPs are intended as both predictive tools for crew coordination, and preventative measures to counter surprise, fear and inappropriate responses. Demonstrably, this works. But we are, after all, humans.

What I am unwilling to broach without substantive evidence is a shift in the characterization of crew responses into another industry which sets aside the old-fashioned notion of competency and how such is achieved.

[rgbrock1]

Ah, but was it surprise or "startle" which affected the PF, or was it abject fear? Was he so preoccupied with the weather that in pulling back and keeping it there (fright response) he thought he was getting out of the cloud layer and into blue skies? And in so focusing on his fright response in obtaining blue skies, he paid absolutely no heed to everything else going on around him?

[OK465]

Two critical cues needed to suss STALL in the A330 Are Buffet and Nose drop. Are these included in the type rating? In the aircraft?

As Perry Mason would say to Hamilton Burger:

"You're on a fishing expedition." :}

[PJ2]

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.

[Organfreak]

rgbrock1:

Ah, but was it surprise or "startle" which affected the PF, or was it abject fear? Was he so preoccupied with the weather that in pulling back and keeping it there (fright response) he thought he was getting out of the cloud layer and into blue skies? And in so focusing on his fright response in obtaining blue skies, he paid absolutely no heed to everything else going on around him?

Of course, we'll never know. But, when it comes to good guesses, I completely agree.

"Scared senseless."

[Linktrained]

"Scared, Surprised, Shocked, Scared-:mad:, Spring-loaded, Shaking, Scared-senseless..."

By chance these are describing in the last few posts how various contributors think that PF may ( or may not) have felt when he used the SS at cruising altitude.

I do not know how often or when last he had done so.

RVSM is mandatory... WHY.... ? ALWAYS....? EVERYWHERE...?

Traffic is dense. We all want the same flight levels ( that was the case before pressurisation too - we all cruised just below 10,000 ft. with quadrantal separation, 500 ft. from crossing aircraft)

Communications are vastly better. Here in my armchair even I can see the radar tracks of many aircraft around the world. There are times and areas where there may be NO other (civil) aircraft anywhere for 100 + miles.

Surely it cannot be beyond a human brain to think of a suitable R/T phrase to allow individual aircraft to fly, released from RVSM, for a finite period.

[Lyman]

Linktrained...

"MAYDAY"? ("m'aider" in French)

[Linktrained]

Lyman,

Legally you must be correct with "Mayday".

I am sorry, I ought to have made it clear that this intended release from RVSM MUST ( not should ) come from Air Traffic Control.

To make this clear, from the ground rather than from the air.

Can you think of a suitable phrase ? Understood by all, as far as you can....

[Lyman]

"conflict"? Doesn't TCAS do this? Certainly, if the altitude alerter fires, it is a/c generated, but TCAS alerts the common comm? if the authority comes down hard on RVSM busts, they can't then refuse the a/c a 7700? In Atlantico, Comms seem problematic on top of everything else? Consider that TCAS is simply a ground installed and remote ATC presence?

[Lonewolf_50]

Lyman to Linktrained.
"MAYDAY"? ("m'aider" in French)

I'll suggest he said merde at least once.

[Lyman]

Merde Jour.......

[bubbers44]

Something like this saying Mayday accomplishes absolutly nothing. I would only say Mayday or declare an emergency if I would get preferential handling, not because my wing fell off and nobody could help me anyway. What's the point?

[Lyman]

bubbers44 Something like this saying Mayday accomplishes absolutly nothing. I would only say Mayday or declare an emergency if I would get preferential handling, not because my wing fell off and nobody could help me anyway. What's the point?

Well, that's you, bub, and they may have considered a MAYDAY "not relevant to the flight", just like BEA may have, and that may be why we do not see it reported. There were several flights in the area, and they had radio access to these crews, to report trouble. If their radios worked. We see almost nothing of what adds up to an absolutely bizarre absence of acknowledgement of their situation. Whether the astonishing lack of chatter in the cockpit, the lack of radio, and the lack of TCAS, something is not adding up.

Take stock of all that is missing, and remember that BEA have purposely and admittedly omitted data. How much? Unknown. What type? Unknown. Initially the BEA stated the RHS was not recorded on the FDR, yet later we see A//P 2 trace, and stick, etc. What about radios, and the initial MEL re comms2? Cockpit heating, wipers, cargo hold temp, RHS NAV/RADAR 2, and FD2 traces? Which Buss carries RHS data to FDR? How did it not get recorded, then simply appear?
Plus all other parameters. What is up with that? The report claims AP2 was recorded, does that mean 'NOT engaged'? Or OFF? Because Captain told us it was selected ON...it may not matter re: flight path, and at the time, recovery was not possible. What it shows is a couple of disconnects in the report?

[Organfreak]

Something like this saying Mayday accomplishes absolutly nothing. I would only say Mayday or declare an emergency if I would get preferential handling, not because my wing fell off and nobody could help me anyway. What's the point?

Well, how about a lengthened version in that case? :
"CAUTION. Flying debris coming to a flight level near you!"? :eek:

[DozyWannabe]

Initially the BEA stated the RHS was not recorded on the FDR, yet later we see A//P 2 trace, and stick, etc.

You misinterpreted the statement. It was the RHS *display* that was not recorded, not the RHS information as a whole.

I'd be prepared to wager a considerable amount that the only data not in the report is the data considered irrelevant. Given that there's a plethora of data available in the report (certainly more than I've seen in previous reports from the NTSB, AAIB and - indeed - earlier BEA reports), I can't see why you're convinced something's being hidden.

[Lyman]

" I can't see why you're convinced something's being hidden."

But much is "hidden", Doze. I propose that much of it is appropriately invisible, but it is a matter of conjecture what relevance it may have.

You are mistaken about the displays being not recorded. The Captain is recorded telling us the AUTOPILOT annunciator is on the screen....Everything was not recorded does not mean the panel was compromised, or replete with dangerous and erroneous data. It simply "was not recorded"

You don't think like I do, Doze, but you may want to count yourself well off in that regard. I spent a year working for the Government, investigating....the Government. I am a trusting and forgiving person at heart, but if I sniff bull ****, and the presence of said bs is meant to fool people, I get right nosy, and persistent.

[DozyWannabe]

The Captain is recorded telling us the AUTOPILOT annunciator is on the screen...

Really? I must have missed that - I read he was heard to confirm and make sure it was off, but maybe you have different data to me.

[EDIT : Confirmed - FDR shows both AP off from initial disengagement to impact.]

[Lyman]

Except for the sound of the selector on the CAM.

[Lyman]

A sister ship to the 330 had an electrical short circuit in flight, and the crew lost half of their ECAM, lost Navigation, had cockpit cabin communication failure, and lost effective control of the stick, along with autopilot.

Any of this sound familiar?

Would you like to read the serious incident report?

[DozyWannabe]

At that point it was just belt-and-braces to make sure it's off. Unlike the FD there is a distinct and specific FDR trace for AP disengagement and it remains OFF throughout the sequence.

It's possible that the Captain had fallen back to a mental mode where he was attempting checklists by rote and simply double-checking all of the points he could remember. Perhaps he was disorientated and misidentified the selector.

In any case as far as the aircraft systems were concerned, the AP was OFF and stayed off.

As to your other points, AF is not a state airline and Airbus is not a state institution. They are both commercial entities in which the French government has a stake - nothing more, nothing less. Hiding problems will always be a self-defeating action - McDonnell Douglas learned that lesson the hard way, and you can bet the French government took notice because the tragedy that brought the secrecy to light happened on their soil. All claims of cover-up and skullduggery on the part of the French regarding Airbus can be traced directly to a single incident where lawyers acting for a defendant in the case leaked unsubstantiated scuttlebutt to the press, who repeated it unchallenged.

A sister ship to the 330 had an electrical short circuit in flight, and the crew lost half of their ECAM, lost Navigation, had cockpit cabin communication failure, and lost effective control of the stick, along with autopilot.

But here we have hard evidence that at least one display was functioning correctly, and no instrumentation other than airspeed was lost. You're trying to draw a false equivalency.

[bubbers44]

I don't think flight 447 was concerned about a mayday call to warn flights below them at that moment. Would you? Mayday will give you priority but over the Atlantic what does it accomplish, nothing.

[Lyman]

Notifying adjacent traffic would accomplish reporting at least, You might be right, they had their hands full, and they may well have decided to remain anonymous. Screwing the Poodle is embarrassing for the French?

[CONF iture]

As I have said many times, even given the pull to stop what may have been perceived as a descent, the airplane settled down quickly and if the PF had done nothing but maintained pitch and power while calling for ECAM Actions while ensuring stable flight, (and 10 to 12deg pitch is NOT stable flight at cruise altitudes!), we wouldnt' be discussing an accident here.
I do agree on that.
That being said, the 12 degrees of pitch was absolutely undesirable, but was not fatal. Some 40 sec after AP disc the situation was borderline but had stopped to deteriorate ... until the FD reappeared and the PF got the bad reflex to follow them. That's when everything took the wrong turn and STALL2 arrived.

Now, that's also the precise moment the trim started to roll ...
It is absolutely unprofessional for the BEA to have omitted to include the full analysis on that matter in their final report.

No misplaced autotrim, and 'we wouldnt' be discussing an accident here'.

[HazelNuts39]

No misplaced autotrim, and 'we wouldnt' be discussing an accident here'. Without autotrim, the PF would have pulled more to follow the FD, or to maintain 15°, or 12.5° pitch, or to arrest the V/S.

[DozyWannabe]

Without autotrim, the PF would have pulled more to follow the FD, or to maintain 15°, or 12.5° pitch, or to arrest the V/S.

Not to mention that the autotrim does not and did not move of its own volition, but moved in response to the consistent and excessive (for the conditions) backpressure on the stick from the PF.

The fact that the A320 seems to have a hard limit on autotrim in Alternate whereas the A330 does not is an interesting line of discussion, but it's not really a subject within the scope of the report.

[rudderrudderrat]

Hi DozyWannabe,
Not to mention that the autotrim does not and did not move of its own volition autotrim will move the stabiliser without any input from PF. If the speed of the aircraft changes, then the trim will run to help the elevator.

Once PF had commanded a pitch attitude which resulted in a real (not just spuriously indicated) speed decay - even if he didn't touch the side stick again - the FBW computers would attempt to maintain that trajectory by moving the elevators and hence the stab trim.

[HazelNuts39]

the FBW computers would attempt to maintain that trajectory by moving the elevators and hence the stab trim. Agreed. But the culprit is not autotrim, without it the airplane would still have stalled.

[RetiredF4]

DW
Not to mention that the autotrim does not and did not move of its own volition, but moved in response to the consistent and excessive (for the conditions) backpressure on the stick from the PF.That´s DozyW´s Oozlum bird. Either you don´t understand the system in the respective Alt2 Law or you don´t want to know.

Without autotrim only the elevators (already in full NU position by the FCS in an attempt to maintain the trajectory while airspeed decaying) would have been available for SS inputs. Then a further nose up command wouldn´t have changed anything. Although there are no data available (as BEA didn´t discuss that matter in the report) it must be assumed, that the pullup would have been terminated earlier with a higher speed. Without autotrim the mentioned neutral stability (mentioned by BEA) could have not be maintained and a significant nosedrop would have been present.

We still don´t know if it would have saved the day though.
ruderruderrat
the FBW computers would attempt to maintain that trajectory by moving the elevators and hence the stab trim. HazelNuts39
Agreed. But the culprit is not autotrim, without it the airplane would still have stalled. If talking about culprit then the law reversion logic comes into my mind. Unlimited Autotrim in ALT2b in conjunction with only BIO-protection seems not a clever idea. Why was the limit of the autotrim in Alt law out-designed in the A330/340 and not retained like in the 320 series? What kind of situation would necessitate an full up THS when careful handling due to the law degradation is necessary?

For BEA the case looks like lost after the aircraft departed the flight envelope. Does that mean, that there was no chance of recovery or that they didn´t look into that matter? THS position and autotrim would play a role when looking into that phase of the flight.

[HazelNuts39]

For BEA the case looks like lost after the aircraft departed the flight envelope.The movement of the elevator and THS in response to sidestick commands is defined by the system and was determined until the end of the flight. The aerodynamic response of the airplane can only be simulated with any confidence within the known flight envelope.

[Lyman]

HazelNuts39

Yes, the aircraft would have Stalled without Autotrim full up. But without the THS authority to keep the Nose Up at STALL, the aircraft's nose may have fallen through, instead of being maintained in the Mush...

No?

( sorry Franzl, missed your post, but it bears repeating, imo)

[HazelNuts39]

the aircraft's nose may have fallen through,Maybe slightly but, IMHO, with full nose-up elevator maintained, not enough to unstall the airplane. I don't expect the airplane to have the straight-wing characteristic of a nose drop that can't be arrested.

[Lyman]

Who would know re: neutral airframe, with the Autotrim busting a gut to keep the flight Path, ?

I don't think the A330 was tested at STALL with full nose up trim? Who would have the balls to do that? And if the a/c can get to STALL by having the flight path seeking it, why isn't the a/c in DIRECT at this point?

If AUTO STALL is available, let's test it in the certs. And at least consider that some additional cue might be helpful...

[Lonewolf_50]

Lyman, I'd like to revisit a fundamental task drilled into pilots from formative days, formative hours. This is in reference to the "mayday call" idea and what raises or lowers the nose.

The fundamental? Aviate. Navigate. Communicate. Given the trouble with the first, any pretense that the last -- calling Mayday or whatever -- has any importance is incorrect.

Aviate.

Pilots are (or should) control the aircraft. If it does X, and X isn't what should be happening, the pilot, using the systems at his disposal, makes it do something else. That is the premise of "controlled flight" versus "uncontrolled flight" or even "passenger in the very front seat."

While the THS certainly helps find a pitch attitude commanded by the system, there is a certain monotony to repeating again and again that the pilots inputs are part of the system. Based on what the FDR data found, the input from the SS was not cut out leaving the pilot at the mercy of the robot.

Why the pilot at the controls kept the nose up is in part (in my mind) explained by the idea that he latched onto the FD as a primary scan item, rather than flying a more primative scan based upon attitude indicator (artificial horizon if you like) compared to other instruments, which takes us back to opinions rendered here on PPRuNe while the BEA were still trying to find the wreckage site deep in the Atlantic Ocean: the Pitch and Power chorus will once again seranade us, since pitch and power comprise fundamental concerns of the fundamental number 1 noted above.

Aviate. Why that broke down seems to have a far heavier HF component (culture, training, and more) than mechanical component, though the complaints on how nuanced the control laws can become in the variety of degraded modes seems to have some merit.

[Lyman]

At four thousand feet, descending at 120 knots, I might consider a last will and testament, though a short one, an aural one, with a keyed mic.

Lonewolf. From the outset of the report of the loss of this a/c, I suspected the pilots were betrayed by the aircraft. I did not necessarily conclude they were without blame, but something did not add up. One of my hundred or so theories early on was that the crew followed the 'bird' into the drink. If ADR can fail, my mindset would be to fly, and trouble shoot. ANC is swell, but sometimes they get rearranged, and there was no teamwork here. I frankly did not suspect any, Teamwork is disincentivised when troubleshooting is trained to be snail paced, and recovering the flight path is URGENT.

Get out the freaking BOOK?

."what raises or lowers the nose."

You forget, the NOSE is secondary. What raises and lowers the tail is the deal.
My instructor told me to be aware of the cause, not the result. Looking at the nose instead of thinking about the tail?

[DozyWannabe]

autotrim will move the stabiliser without any input from PF. If the speed of the aircraft changes, then the trim will run to help the elevator.

Agreed.

Once PF had commanded a pitch attitude which resulted in a real (not just spuriously indicated) speed decay - even if he didn't touch the side stick again - the FBW computers would attempt to maintain that trajectory by moving the elevators and hence the stab trim.

Which was the point I was making. Autotrim was trying to compensate for the simultaneous fall-off in airspeed *and* the commanded nose-up attitude, both of which were directly attributable to the PF's backstick commands.

@franzl - If I had to guess, I'd say that the autotrim limitation might have been dropped for the widebodies due to criticism from some pilots over not having full authority through the PFCs in Alternate Law.

[Lyman]

Quote:
Once PF had commanded a pitch attitude which resulted in a real (not just spuriously indicated) speed decay - even if he didn't touch the side stick again - the FBW computers would attempt to maintain that trajectory by moving the elevators and hence the stab trim.

Even if the pilot had let go the stick following his first input of NU, the a/c would have flown into STALL. This means the pilot is constantly responsible for Pitch, but cannot relax the stick either, setting up a lethal and terminal misunderstanding of flight path in an upset a/c. Peachy.

Alternate Law in upset is absurd. And deadly.

[Machinbird]

Lyman
You forget, the NOSE is secondary. What raises and lowers the tail is the deal.Come on. Which end of the teeter totter is going up? Completely irrelevant point IMO.

[Lyman]

Bear with me Commander, my teacher had an angle, and it served me well. Step back, and see if you do not agree. Airbus and aviation are dumbing down the pilot pool.

Jim G was a Naval Aviator. Corsairs. The ones with propellers. He taught me to constantly assess what the aircraft was doing, and the controls part in it. He may have said something like, " if you think something is wrong, it is. Otherwise you don't understand your airplane." He taught feel. If he hadn't flown his Baron into that building, he'd be all over this case.

(get home- itis.)

[gums]

Here's the snip from the FCOM I have been given from one of the pilots here:

http://www.sluf.org/misc_pages/a330_flight_mode.jpg

I can't find any clear reference to "auto-trim" until "Direct Law".

Note that the THS seems to follow pilot inputs except when AoA "protection" is active, and in our case HAL decided AoA was irrelevant. GASP!

Maybe A33Z can help here.

So I'll throw my vote in with several here that the THS auto-trim feature did not help the situation, and may have contributed to the stall entry and remaining in the stall unless the pilot commanded nose down/lower gee than "one".

I continue to iterate that the 'bus system is not an "attitude" command but a gee command. Because HAL corrects for pitch attitude, the basic one gee command is "corrected". So you think the jet is trying to maintain an attitude, but that's just a result of the corrected gee comand. Additionally, without auto-throttle, the only speed stability is when drag equals thrust, and it is not what we old dinosaurs were used to when the plane tried to achieve the trimmed AoA ( and resulting drag versus lift properties).

So way I read things, the plane would have trimmed for one gee corrected for 10 or 12 degrees pitch even if the pilot let go of the stick. The THS eventually reaches max and.........

[Clandestino]

Issue with BEA investigators is they had expert help at hand, they correctly understand how Airbus FBW works and are fully aware what "acceptable by certification authorities" means.

PPRuNers have no such resources readily available, therefore I find it unsurprising that some only slightly wrong theories about how Airbus FBW works resulted in quite flawed assumptions being passed as facts, leading to another oozlumistic round of suspicious glances being cast towards BEA, DGAC and Airbus.

Let's get to basics of aircraft stability: conventional certification rules state that no passenger transport aircraft will get certified unless she displays adequate static and dynamic stability in pitch. Static stability means aeroplane, when disturbed from trimmed speed, will return to it stick-free. Dynamic stability means it will do so in acceptable number of convergent oscillations. Stability is not just a matter of aerodynamics; control forces, controls architecture and power all affect it so it can be (and mostly is) significantly modified by FBW. FBW Airbi can not demonstrate hands-off stability in normal and alternate laws as due specific settings of their FBW they will not make an attempt to return to trimmed speed after the stick is released.

As for how Airbus FBW works, lets first start with how it doesn't. It was said it maintains 1g. It was said it maintains pitch. It was said it maintains alpha. In normal operation, none of this is true. It might maintain all three of it but not because it pursues them actively but only as a consequence of trying to maintain constant flightpath when stick is pitch neutral.

So how it works for the pilot? First we'll assume steady, level manual flight with ATHR in SPEED mode (to digress a bit: most of the world flies this way while my company was pretty adamant: manual flight - manual thrust, no matter if it is Boeing or Airbus or whatever). If there's moderate pull or push and then release to neutral, FBW will maintain new flightpath, autothrust will compensate with thrust change, aeroplane will feel pitch neutral. So far so good.

Now let's assume ATHR is off, aeroplane is flying straight&level and a couple of degrees of pitch up are introduced while thrust remains constant. Aeroplane tries to maintain the flightpath but as some power now has to be used to climb, drag causes the aeroplane to decelerate. As it decelerates, it needs more AoA to keep the fligtpath so FCS introduces a little more pitchup on its own. Aeroplane feels slightly unstable but if power and pitch are reasonable, equilibrium point where the new flightpath can be maintained without further increase in alpha is met. Still good.

If we take extreme case, where aeroplane is flying straight & level and TLs are moved to idle, aeroplane indeed starts to pitch up on her own as the speed is bled off. How long does it pitch-up? Until alpha prot activates in normal law, low speed stability kicks in in alternate1 and introduces pitch-down or it stalls in alternate2.

So why is it all so seemingly complicated? Simples. To make life easier for mister pilot and provide him with perfectly conventional control response within the envelope. There is absolutely no need to think about flightpath or trim. Stick forward moves nose down. Stick backward moves nose up. Stick left rolls the aeroplane left. No points for guessing what does stick right. Many a claim was made on this rumour network that oh-so-complicated-Airbus-took-the-controls-away-from-me-when-it-shouldn't-have. None of them were substantiated except St.Johns and Bilbao - that's fixed now.

While the nomenclature between SA and TA Airbi is different, principles of protections are pretty similar. We didn't call it ALT1 and ALT2 when I was on 319. Their rough equivalents are "alternate with reduced protections" and "alternate without protections" (nitpickers, welcome).

How do I know AF447 wasn't deep-stalled? Well, I started by paying attention in high school science classes, which helped me to understand aerodynamics lessons during my flight training. One of them involved deep stall and I learnt it has specific meaning: it is stall which cannot be recovered by conventional means such as actions on elevator, stabilizer or power. While AF447 never fully recovered, mere reduction of power or just moving the elevators towards the neutral (while never reaching it) abruptly decreased its AoA - which is incompatible with deep stall as we know it. Now if your goal is to be taken seriously in discussion, you won't go a long way if you take well established terms and start assigning them just your own definitions.

Alternate Law in upset is absurd. And deadly. If it were true, then dr. Evil Genius who invented should be stripped off of his PhD! He has less than three percent success in catching the crews in his trap!

Seriously, these unsubstantiated claims are so repetitive I can't even find them humorous anymore.

This means the pilot is constantly responsible for PitchIs it news for anyone else? :hmm:

At four thousand feet, descending at 120 knots, I might consider a last will and testament, though a short one, an aural one, with a keyed mic.Hollywood's bravo sierra. In their minds, crew was fighting for their lives until the end, there was no time for pathetic farewells. That they completely misunderstood their enemy and eventually committed the suicide by incompetence is tragic, not stupid.

I suspected the pilots were betrayed by the aircraft.Harsh words, but if we assume they're true then so were others. Difference is they choose more appropriate response, even if it meant doing nothing at all while been confused about what is happening.

I don't think the A330 was tested at STALL with full nose up trim? Who would have the balls to do that? Using brain instead of balls tends to produce better outcomes. Like not even trying what was computed to be fairly suicidal.

Does that mean, that there was no chance of recovery or that they didn´t look into that matter? Looking into that matter could turn out to be very expensive... not just in Euros but also in lives.

A sister ship to the 330 had an electrical short circuit in flight, and the crew lost half of their ECAM, lost Navigation, had cockpit cabin communication failure, and lost effective control of the stick, along with autopilot.

Any of this sound familiar?No. Reference, please.

Normally all training is pre-briefed, so when the event happens in the simulator, there is no "surprise".Glad I work for abnormal outfit.

The real question is why a relatively simple loss of air data lead to such a monumental "cock up". Panic.

I am sure they are quite familiar to AB pilots. Still I think that the briefness of the messages can add to the congnitive stress situations more than ease it. When ECAM works as designed and is faced with simple faults, it covers everything you need to know and do. No more, no less. No point putting "pretty please with sugar on top" on ECAM lines.

I think the report alludes to the less than optimum task load for the PNFYup. Proper flightpath control was never achieved and that always takes precedence over ECAM actions.

Perhaps this correlation is not appropriate and I'm sure I'll be called out if it is. But, me thinks it is indeed appropriate. I suppose it is even more appropriate than you assume it is.

Perhaps it is leftover in our DNA from the times our ancestors were preyed upon by cave hyenas and short-faced bears but there are two main types of panicky reaction: getting frozen (maybe the hunter won't spot you if you don't move) or running away in whatever direction (this might help confuse the predator or make it catch someone slower). Seems to me that it was very unfortunate set of events that both pilots simultaneously fell victim to panic. CM2 was trying to run away from the danger he sensed was coming from below and had no understanding for the aeroplane's energy state while CM1 got too scared to intervene. IMHO another important aspect of your story is that your comrades, while doubtlessly well trained, were simultaneously faced with realization that they are not in training anymore, that (unlike drill sergeants who just play-pretend) folks out are there are really bent on killing them and that not everything is going according to the plan. Sudden realization of one's own mortality can easily set the atavistic instincts in motion.