AF 447 Thread No. 9
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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.
Lyman:
Lyman, have you taken a look at where the avionics are located in an A330? I refer to the heat producing items.
A fan motor might, but which one are you referring to? A vent fan?
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???
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.
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?
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)?
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
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???
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.
Last edited by Lonewolf_50; 17th Jul 2012 at 19:45.
buffet, buzz and "touch"
@ 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.
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.
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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!!!
"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!!!
Last edited by rgbrock1; 17th Jul 2012 at 19:49.
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Stories
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.
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.
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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".
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".
Last edited by jcjeant; 17th Jul 2012 at 20:26.
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.
That "very short time" was two hours.
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.
Possibly. Maybe it goes even deeper, down to flight schools and "Principles of flight" lessons.
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.
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.
Actually, I was mistaken. It was ten times as much.
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.
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.
IMHO, magenta line on real fig 64 (report in French) makes one of the most depressing reads in the report.
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 TAT has warmed from -42°C to -38.8°C over a very short time.
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.
Originally Posted by Lonewolf 50
The PF was task saturated.
Originally Posted by Lonewolf 50
Training issue, and possibly an Airbus and Air France Indoctrination Issue. Education and training go hand in hand with indoctrination.
Originally Posted by gums
For those that have not flown a FBW system
Originally Posted by gums
And now, Airbus shows us that the jet DOES HAVE a point on the pitch coefficient curve that is "neutral".
Originally Posted by gums
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.
Originally Posted by gums
The high-speed indications for sub-sonic designs usually involve a high frequency "buzz" or vibration.
Originally Posted by 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?
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Cost Benefit Analyses
Lonewolf50
I have known some of the 
'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.
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 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).
'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.
FBW laws and history
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:
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.
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.
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.
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.
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.
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.
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.
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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.
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.
Last edited by Lyman; 18th Jul 2012 at 00:25.
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Originally Posted by Lonewolf_50
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).
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 ?
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Originally Posted by 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.
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
, but we will never know.
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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"...
Last edited by Lyman; 18th Jul 2012 at 02:42.
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!
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!
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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...
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Relevant
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.
(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.
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Thread Starter
Ref post 506 ..
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 ..
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 ..
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RetiredF4
When pitch is established (lets sáy 10°) and the aircraft is decelerating, the body would feel a descending sensation even if still climbing.
When pitch is established (lets sáy 10°) and the aircraft is decelerating, the body would feel a descending sensation even if still climbing.
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.
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.
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".
The thing is programmed to hold a gee!
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.