AF447 wreckage found
Boy there is some crap in here!!
Now read my lips:- In Alternate Law the aircraft flies basically like normal BUT without most protections. It doesn't use pitch trim for pitch!!
ALTERNATE 1. You can barrel roll the beast
ALTERNATE 2. You can barrell roll AND loop the beast.
( I may have these two backwards!! )
I've tried my Garmin GPS in the cockpit of the 330 and the 777 and it takes along time to log on to the satellites and drops out easily. This is most likely due to the thick gold lined heated windows and all the RF interference in the cockpit.
Now I don't mean to be disrespectful of the deceased but there has been enough information from Airbus and Boeing concerning these type of events for these guys to have learned from the past and prepared themselves accordingly. They either didn't know how to revert to "basics" or they were just slack....( ie they weren't famiar with their QRH )
Now read my lips:- In Alternate Law the aircraft flies basically like normal BUT without most protections. It doesn't use pitch trim for pitch!!
ALTERNATE 1. You can barrel roll the beast
ALTERNATE 2. You can barrell roll AND loop the beast.
( I may have these two backwards!! )
I've tried my Garmin GPS in the cockpit of the 330 and the 777 and it takes along time to log on to the satellites and drops out easily. This is most likely due to the thick gold lined heated windows and all the RF interference in the cockpit.
Now I don't mean to be disrespectful of the deceased but there has been enough information from Airbus and Boeing concerning these type of events for these guys to have learned from the past and prepared themselves accordingly. They either didn't know how to revert to "basics" or they were just slack....( ie they weren't famiar with their QRH )
Last edited by nitpicker330; 29th May 2011 at 04:07.
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Well, the three pilots are all dead and cannot defend themselves. What we have are mere recordings which all the anal retentive techies think are infallible data telling the whole story. Well the recordings might have been correct but from erroneous instrumentations! Next, we have to consider how the erroneous readings and data were presented in the cockpit at the time of the accident.
Then let's consider the effects of continuous training in the sim year after year factored in the f/os' reaction to the confusing data presented in the cockpit. You will find training mainly focussed on windshear recovery, CFIT recovery and even stall recovery which calls for minimum loss of altitude in the sim nowadays. Their lack of experience or lack of presence of mind when faced with the confusing situation somehow regressed them to the reactions when faced with windshear as per their sim training year after year.
Then let's consider the effects of continuous training in the sim year after year factored in the f/os' reaction to the confusing data presented in the cockpit. You will find training mainly focussed on windshear recovery, CFIT recovery and even stall recovery which calls for minimum loss of altitude in the sim nowadays. Their lack of experience or lack of presence of mind when faced with the confusing situation somehow regressed them to the reactions when faced with windshear as per their sim training year after year.
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I think by now we know the FO flying totally screwed up. Pulling the nose up in a stall is opposite of any other stall recovery procedure. You always lower the nose and add power. We learned that in the Cessna 150. It works for all Boeings also. Airbus came up with this concept that you could just pull back the control and the computer wouldn't let you stall. Well, what if the computer fails? It obviously failed this time and over 200 people died for no reason. When will Airbus give up on the automatic airplane and pilots can be stupid and still fly it approach. Maybe they need to hire qualified pilots and let the 250 hr wonders pay their dues and do something doing actually flying for a while before they get in the right seat.
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Among the many differences between flying a small airplane and a big airliner, especially one with the Airbus's "fly by wire" control system, is that in some circumstances the right response in an Airbus can be to raise the nose. Please don't mention a Cessna. Regardless, if they had lost all their instruments, and with no visible horizon, even an exceptionally well trained and experienced professional pilot would have lost situational awareness and would not have been able to discern the pitch attitude of the aircraft.
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Two words describe best the action of the pilots and in particular the captain who thought it a good idea to take a break in the middle of the worst area of weather: criminal negligence.
Plastic PPRuNer
I think it must have been very confusing to rapidly transition from a quiet cockpit to one with multiple distracting flashing and aural alarms, simultaneous contradictory loud annunciations and inconsistent instrument readings.
In the face of all drummed-in belief in the peerless automations, to discard all these, go to Direct or Mechanical Law, zero the trim and fly a standard EPR, uncage and follow the standby Attitude Indicator & Altimeter and all this very quickly would demand a special kind of cool and experience.
In the face of all drummed-in belief in the peerless automations, to discard all these, go to Direct or Mechanical Law, zero the trim and fly a standard EPR, uncage and follow the standby Attitude Indicator & Altimeter and all this very quickly would demand a special kind of cool and experience.
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mac the knife,
Is this supposed to be some kind of defense?
These highly paid pilots are expected to be able to handle such situations with ease. Ok so wow, they had to fly in the middle of the night, over the ocean, it was no doubt cold outside and windy and perhaps the seats were so comfortable that they felt sleepy and staring out of a window for hours at blackness is boring. Oh and we must sympathize that flashing lights are just too damn distracting.
Hello? They are supposed to be professionals. If they can't do their duty because of the above factors then they have no place in a cockpit. If i pay 500 euros for a flight i damn well expect the pilots do be competent enough to handle whatever inconveniences or distractions that might occur during their duty. Over 200 lives were lost because it seems the pilots didn't know what to do once the autopilot stopped flying the plane.
Anyone with a little bit of training on simulators can fly an airbus using the autopilot for 99% of the flight including ILS landing. But these pilots are paid for when the **** hits the fan and for their expertise, skills and judgement in those rare situations when the plane doesn't just fly itself for you.
Given what we know thus far, i expect trials will find the pilots criminally negligent and there will be huge compensation for the families.
Is this supposed to be some kind of defense?
These highly paid pilots are expected to be able to handle such situations with ease. Ok so wow, they had to fly in the middle of the night, over the ocean, it was no doubt cold outside and windy and perhaps the seats were so comfortable that they felt sleepy and staring out of a window for hours at blackness is boring. Oh and we must sympathize that flashing lights are just too damn distracting.
Hello? They are supposed to be professionals. If they can't do their duty because of the above factors then they have no place in a cockpit. If i pay 500 euros for a flight i damn well expect the pilots do be competent enough to handle whatever inconveniences or distractions that might occur during their duty. Over 200 lives were lost because it seems the pilots didn't know what to do once the autopilot stopped flying the plane.
Anyone with a little bit of training on simulators can fly an airbus using the autopilot for 99% of the flight including ILS landing. But these pilots are paid for when the **** hits the fan and for their expertise, skills and judgement in those rare situations when the plane doesn't just fly itself for you.
Given what we know thus far, i expect trials will find the pilots criminally negligent and there will be huge compensation for the families.
Last edited by wafelbolletjes; 29th May 2011 at 07:07.
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Stabilizer or De-Stabilizer? It's Becoming a Focus of the AF447 inability to recover
As some technical "niceties" about the auto-trim system starts to emerge, it's beginning to sound as if the vagaries of the auto-trim system in respect of Airbus Law Change philosophy were instrumental in the inability of the AF447 crew to recover from the type of stall that they'd entered. i.e. they may have been victims of the circumstances of their stall entry scenario. To explain:
a. During the zoom climb to FL380 (in Alternate Law) the auto-trim transitioned from 3 deg N/up to 13 degs n/up (near to, if not max nose-up THS trim for the type).
b. Upon entering the stall ballistically and starting its "deep"-stalled descent, the aircraft would have been (and remained) in Abnormal Law, with the auto-trim inop and the trimmable horizontal stabilizer (THS) therefore locked at 13 degs nose-up..... unless it was to be manually changed by the pilot (and we now know that it was not).
c. The engines were at TOGA at this stage, so we have the pitch-up effect of TOGA power plus the THS "stuck" (i.e. de-automated) at 13 degs nose up.... both tending to pitch-up and support a stall continuance..... no matter what the pilots did (unless they were to change the acft configuration somehow - aerodynamically or CofG wise).
d. Airline pilot exposure to stalling tends to concentrate upon the approach to the stall and recovery (i.e. avoidance) with minimum altitude loss. In that stock standard scenario, one of the primary and persistent preliminaries in the incipient stall experience is the airframe buffeting and stick-shaker progression. This is de rigeur in a standardised level 1kt/sec deceleration towards a level 1g stall and is the cue for the trainee to take recovery action. However, if one enters a stall ballistically at high altitude, will there be any buffeting? The AoA system will issue a stall warning but is this against a distracting background medley of other aural alarms? Stall recognition and realisation then becomes an obscurity of the first order.
So the question now becomes: "What would be required to un-stall this aircraft (now in Abnormal Law) if there is insufficient elevator authority at 13 degs nose-up THS to get the nose down (and thus air over and across the wings and tail), during a stall locked in at 40 degs AoA (as predicated by their entry config)?" One answer might be: "Idle the power" (and this was done soon after the captain re-entered the flight-deck, possibly because he'd just misinterpreted their predicament as a L.o.C., based upon a quick scan). Another might be: "Manually run the trim" (i.e. not something that comes naturally to an Airbus pilot - particularly not if he's unclued and quite unaware that the 13 deg nose-up THS is now his basic problem). A pilot's normal cueing to adjust trim is that the airplane is "out-of-trim" and tending to deviate from a chosen flight-path i.e. not a player in this deep-stall scenario.
Three questions: 1. "Will the pilot be aware that he's in abnormal Law? (and the portents of that)" The answer might well be: "Probably not" (there's nothing to promote awareness of this being the case i.e. no aural annunciation - and thus we arrive at: what now needs to be done that's essential for recovery?)
2. "Does the elevator alone have sufficient authority to unstall the wings at max power or at idle?" The answer is probably not, at least not while the superior trim authority of the THS at 13 degs n/up holds sway.... and particularly not whilst at TOGA power.
3. "Why doesn't the elevator have sufficient authority to unstall?" The whole design premise of the THS is to reduce trim drag and allow the elevator to become more of an active trim and less of a primary flight control. This ideation works well 99.99% of the time and it's used in all models of airliners to some degree. They need the capability of coping with large CofG ranges to accommodate loading, fuel burn-off and configuration changes. Some aircraft augment this capability with tail-located fuel trim-tanks. However this minimalistic elevator design feature in the A330 apparently won't "work" in the progression of events that AF447 underwent.
So are Airbus elevator throws and areas (i.e. authority) an under-design or does the THS have undue authority? That becomes the question here as we switch our attention to not blaming the pilots but agonizing over possible Airbus design deficiencies. But before we look into that, we need to pose the question: "Were the AF447 pilots aware that they were locked in an aerodynamic stall?" I'd suggest that they were NOT..... mainly because of the circumstances of their entry being wholly unfamiliar..... and that medley of aural alarms mentioned earlier that had overloaded their capacity to assimilate transient info. It's called cognitive disequilibrium, an idiosyncratic need to ignore or de-prioritize - a close relative of cognitive dissonance (a tendency to rigorously deny or disbelieve), two behavioral paradigms to which professional pilots are prone. One final thought, centering upon human factors. When the captain entered the cockpit and tried to take it all in at a glance one of the things he would've missed, because of its positioning, is what the pilot's input was on his sidestick. With a yoke (thinking of Egyptair MS990 here) it's visually apparent that what's afoot is directly related to pilot action. Food for thought.
Are there any precedents in the Airbus incident and accident annals? There's the Air New Zealand A320 test-flight crash and the Tarom Airbus near accident on ILS finals at CDG..... that spring to mind.
It's worth citing an extract from the Tarom incident: "Under the aerodynamic effect of this THS deflection (of 13 degs) and under the mechanical effect of thrust, the aircraft was thus subjected to a nose-up force that could not be controlled by elevators. It rapidly assumed an extreme pitch attitude and angle of attack.
There may be others. The 1994 crash on go-round of a (non-FBW) A300 at Nagoya? (link). Para 4.2.b of this link lists 6 Airbus incidents and one B747 involving pitch-trim anomalies. An extract from that Nagoya narrative might help emphasize the sometimes inordinate power of a THS in some circumstances: After the PF inadvertently pressed TOGA on finals,
"The autopilot automatically went into GA mode, and this would have shown on the primary flight display (a very vague alert really). The aircraft was flying 18 degrees nose-up, normal for a go-around, but the FO was pushing heavily on the yoke to get the nose down. He was meeting heavy resistance, a design indication on almost all airplanes that that his manual commands were in conflict with the autopilot. For nearly 20 seconds, as he applied down-elevator, the autopilot moved the trimmable horizontal stabilizer (THS) in the opposite direction to keep the nose up. At T+30, THS reached maximum nose-up; at T+42, the autopilots were disengaged. Pilot C asked for autothrottles engaged and took control, increasing down elevator to full deflection as the aircraft began climbing. Alpha-floor (an Airbus automatic protection mode) triggered at T+50 from excessive AOA. Alpha-floor triggered maximum thrust for climb-out, but that added thrust in fact increased the nose-up attitude to 52.6 degrees (one may surmise that the thrust centerline is below the rotational center of the airplane, and at low speed there is not much aerodynamic force to maintain resistance to this rotation). (52.6 degrees is very steep. A high-friction granite rock face of this angle would nevertheless be considered a technical rock climb.) C disengaged alpha-floor by retarding thrust and tried to get the nose down again with trim. Airspeed had dropped to 78 kt., the aircraft stalled at 1,800 ft, and control was not regained before it hit the ground."
If the BEA Inquiry into AF447 heads down this well-trammeled path towards THS excess authority and control law anomalies in stalls, Airbus is going to have to do the old quickstep that they've always done so well - in order to avoid changing physical design. No doubt it will take the form of a circuitous software patch to the control laws and/or yet another aural alarm and cautionary bulletin.
Edited to add:
However, despite all of the above, there is no denying that “no clear-cut stall recognition and persistent warning” is the apparent deficiency that put AF447 into the Atlantic. Recognizing that the overwhelmed pilot can become clueless in a time of great stress, perhaps aural alarms should become aural admonitions: as in “Stall Warning. Reduce angle-of-attack and trim nose-down for recovery”
a. During the zoom climb to FL380 (in Alternate Law) the auto-trim transitioned from 3 deg N/up to 13 degs n/up (near to, if not max nose-up THS trim for the type).
b. Upon entering the stall ballistically and starting its "deep"-stalled descent, the aircraft would have been (and remained) in Abnormal Law, with the auto-trim inop and the trimmable horizontal stabilizer (THS) therefore locked at 13 degs nose-up..... unless it was to be manually changed by the pilot (and we now know that it was not).
c. The engines were at TOGA at this stage, so we have the pitch-up effect of TOGA power plus the THS "stuck" (i.e. de-automated) at 13 degs nose up.... both tending to pitch-up and support a stall continuance..... no matter what the pilots did (unless they were to change the acft configuration somehow - aerodynamically or CofG wise).
d. Airline pilot exposure to stalling tends to concentrate upon the approach to the stall and recovery (i.e. avoidance) with minimum altitude loss. In that stock standard scenario, one of the primary and persistent preliminaries in the incipient stall experience is the airframe buffeting and stick-shaker progression. This is de rigeur in a standardised level 1kt/sec deceleration towards a level 1g stall and is the cue for the trainee to take recovery action. However, if one enters a stall ballistically at high altitude, will there be any buffeting? The AoA system will issue a stall warning but is this against a distracting background medley of other aural alarms? Stall recognition and realisation then becomes an obscurity of the first order.
So the question now becomes: "What would be required to un-stall this aircraft (now in Abnormal Law) if there is insufficient elevator authority at 13 degs nose-up THS to get the nose down (and thus air over and across the wings and tail), during a stall locked in at 40 degs AoA (as predicated by their entry config)?" One answer might be: "Idle the power" (and this was done soon after the captain re-entered the flight-deck, possibly because he'd just misinterpreted their predicament as a L.o.C., based upon a quick scan). Another might be: "Manually run the trim" (i.e. not something that comes naturally to an Airbus pilot - particularly not if he's unclued and quite unaware that the 13 deg nose-up THS is now his basic problem). A pilot's normal cueing to adjust trim is that the airplane is "out-of-trim" and tending to deviate from a chosen flight-path i.e. not a player in this deep-stall scenario.
Three questions: 1. "Will the pilot be aware that he's in abnormal Law? (and the portents of that)" The answer might well be: "Probably not" (there's nothing to promote awareness of this being the case i.e. no aural annunciation - and thus we arrive at: what now needs to be done that's essential for recovery?)
2. "Does the elevator alone have sufficient authority to unstall the wings at max power or at idle?" The answer is probably not, at least not while the superior trim authority of the THS at 13 degs n/up holds sway.... and particularly not whilst at TOGA power.
3. "Why doesn't the elevator have sufficient authority to unstall?" The whole design premise of the THS is to reduce trim drag and allow the elevator to become more of an active trim and less of a primary flight control. This ideation works well 99.99% of the time and it's used in all models of airliners to some degree. They need the capability of coping with large CofG ranges to accommodate loading, fuel burn-off and configuration changes. Some aircraft augment this capability with tail-located fuel trim-tanks. However this minimalistic elevator design feature in the A330 apparently won't "work" in the progression of events that AF447 underwent.
So are Airbus elevator throws and areas (i.e. authority) an under-design or does the THS have undue authority? That becomes the question here as we switch our attention to not blaming the pilots but agonizing over possible Airbus design deficiencies. But before we look into that, we need to pose the question: "Were the AF447 pilots aware that they were locked in an aerodynamic stall?" I'd suggest that they were NOT..... mainly because of the circumstances of their entry being wholly unfamiliar..... and that medley of aural alarms mentioned earlier that had overloaded their capacity to assimilate transient info. It's called cognitive disequilibrium, an idiosyncratic need to ignore or de-prioritize - a close relative of cognitive dissonance (a tendency to rigorously deny or disbelieve), two behavioral paradigms to which professional pilots are prone. One final thought, centering upon human factors. When the captain entered the cockpit and tried to take it all in at a glance one of the things he would've missed, because of its positioning, is what the pilot's input was on his sidestick. With a yoke (thinking of Egyptair MS990 here) it's visually apparent that what's afoot is directly related to pilot action. Food for thought.
Are there any precedents in the Airbus incident and accident annals? There's the Air New Zealand A320 test-flight crash and the Tarom Airbus near accident on ILS finals at CDG..... that spring to mind.
It's worth citing an extract from the Tarom incident: "Under the aerodynamic effect of this THS deflection (of 13 degs) and under the mechanical effect of thrust, the aircraft was thus subjected to a nose-up force that could not be controlled by elevators. It rapidly assumed an extreme pitch attitude and angle of attack.
There may be others. The 1994 crash on go-round of a (non-FBW) A300 at Nagoya? (link). Para 4.2.b of this link lists 6 Airbus incidents and one B747 involving pitch-trim anomalies. An extract from that Nagoya narrative might help emphasize the sometimes inordinate power of a THS in some circumstances: After the PF inadvertently pressed TOGA on finals,
"The autopilot automatically went into GA mode, and this would have shown on the primary flight display (a very vague alert really). The aircraft was flying 18 degrees nose-up, normal for a go-around, but the FO was pushing heavily on the yoke to get the nose down. He was meeting heavy resistance, a design indication on almost all airplanes that that his manual commands were in conflict with the autopilot. For nearly 20 seconds, as he applied down-elevator, the autopilot moved the trimmable horizontal stabilizer (THS) in the opposite direction to keep the nose up. At T+30, THS reached maximum nose-up; at T+42, the autopilots were disengaged. Pilot C asked for autothrottles engaged and took control, increasing down elevator to full deflection as the aircraft began climbing. Alpha-floor (an Airbus automatic protection mode) triggered at T+50 from excessive AOA. Alpha-floor triggered maximum thrust for climb-out, but that added thrust in fact increased the nose-up attitude to 52.6 degrees (one may surmise that the thrust centerline is below the rotational center of the airplane, and at low speed there is not much aerodynamic force to maintain resistance to this rotation). (52.6 degrees is very steep. A high-friction granite rock face of this angle would nevertheless be considered a technical rock climb.) C disengaged alpha-floor by retarding thrust and tried to get the nose down again with trim. Airspeed had dropped to 78 kt., the aircraft stalled at 1,800 ft, and control was not regained before it hit the ground."
If the BEA Inquiry into AF447 heads down this well-trammeled path towards THS excess authority and control law anomalies in stalls, Airbus is going to have to do the old quickstep that they've always done so well - in order to avoid changing physical design. No doubt it will take the form of a circuitous software patch to the control laws and/or yet another aural alarm and cautionary bulletin.
Edited to add:
However, despite all of the above, there is no denying that “no clear-cut stall recognition and persistent warning” is the apparent deficiency that put AF447 into the Atlantic. Recognizing that the overwhelmed pilot can become clueless in a time of great stress, perhaps aural alarms should become aural admonitions: as in “Stall Warning. Reduce angle-of-attack and trim nose-down for recovery”
Last edited by TheShadow; 29th May 2011 at 07:35.
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Originally Posted by wafelbolletjes
Two words describe best the action of the pilots and in particular the captain who thought it a good idea to take a break in the middle of the worst area of weather: criminal negligence.
. Do come back later once you know what you are talking about. In the meantime stop wasting my time reading such crap.
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Maybe they need to hire qualified pilots and let the 250 hr wonders pay their dues and do something doing actually flying for a while before they get in the right seat.
A newbie 250 hour wonder probably would have had better CRM, more recent and genned up on the flight control systems.
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Excellent analysis from The Shadow.Frightening though.I looked at this accident from the POV of a pilot of a real plane that does what you ask and never does things subtly without you knowing only to leave you unprotected at the worst moment possible.My mistake.So auto trim is not so cool after all.I wont comment further because it will be bad for my blood pressure.I see the pilot's predicament in a new light though after the Shadow's post and I think it is definitely mitigating.
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While TheShadow's points may be valid, they don't excuse the pilots for not even trying to point the plane's nose downwards (for the last 3 minutes). It also doesn't excuse the pilots for not realizing that the plane was in fact stalled. If it's going down at 10k fpm with nose up attitude and full throttle then, duh, it must be stalled.
If the pilots had however been pushing forward on the sidesticks and screaming about how the plane was stalled on the CVR then we can solely lay the blame on airbus design flaws. But that's not the case. I won't comment again because it is clear the pilots here will never lay the blame on fellow pilots. I'll no doubt be labelled an idiot but at least i am not an idiot responsible for the death of over 200 innocent adults and children.
If the pilots had however been pushing forward on the sidesticks and screaming about how the plane was stalled on the CVR then we can solely lay the blame on airbus design flaws. But that's not the case. I won't comment again because it is clear the pilots here will never lay the blame on fellow pilots. I'll no doubt be labelled an idiot but at least i am not an idiot responsible for the death of over 200 innocent adults and children.
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ZBMAN
Fully agree with you.
WaffelPlease go back to your Flightsim and enjoy.The problem is this is an open forum and then we waste time reading loads of crap here.
It's tiring, boring to try to explain the basics to people like you, sorry.
BTW, congrats on the brilliant post "The Shadow"! You counterbalance at least ten of the b****ters.
Keep up the good job.
WaffelPlease go back to your Flightsim and enjoy.The problem is this is an open forum and then we waste time reading loads of crap here.
It's tiring, boring to try to explain the basics to people like you, sorry.
BTW, congrats on the brilliant post "The Shadow"! You counterbalance at least ten of the b****ters.
Keep up the good job.
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Will the pilot be aware that he's in abnormal Law? (and the portents of that)" The answer might well be:[COLOR=SlateGray][I] "Probably not" (there's nothing to promote awareness of this being the case i.e. no aural annunciation - and thus we arrive at: what now needs to be done that's essential for recovery?)
AH no??? The PF announces Alternate Law when he takes manual control of the aircraft. It is in one of the first lines in the BEA communication !!!
2. "Does the elevator alone have sufficient authority to unstall the wings at max power or at idle?" The answer is probably not, at least not while the superior trim authority of the THS at 13 degs n/up holds sway.... and particularly not whilst at TOGA power.
In ALT LAW with AP an AT off there is virtually no Stall protection left. The THS goes where the pilot wants it to go. It simply responded to the pitch-up inputs by the pilot to 'help' him go where he wants. Had he made pitch-down inputs afterwards it would simply have gone in the other way, although it would take a continuous pitch-down input for some time.
AH no??? The PF announces Alternate Law when he takes manual control of the aircraft. It is in one of the first lines in the BEA communication !!!
2. "Does the elevator alone have sufficient authority to unstall the wings at max power or at idle?" The answer is probably not, at least not while the superior trim authority of the THS at 13 degs n/up holds sway.... and particularly not whilst at TOGA power.
In ALT LAW with AP an AT off there is virtually no Stall protection left. The THS goes where the pilot wants it to go. It simply responded to the pitch-up inputs by the pilot to 'help' him go where he wants. Had he made pitch-down inputs afterwards it would simply have gone in the other way, although it would take a continuous pitch-down input for some time.
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anyone else feel that this post is totally pointless ???
Everyone posting their own take on the situation then using it to back their own particular hobby-horse (AB, Boeing, manual flying, anti-French, conspiracy theorists, etc etc ) and then slaggong off everyone else
really depressing TBH
Everyone posting their own take on the situation then using it to back their own particular hobby-horse (AB, Boeing, manual flying, anti-French, conspiracy theorists, etc etc ) and then slaggong off everyone else
really depressing TBH
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To TheShadow:
As the voice recorder proofs, they knew very well, see the report.
The PF didn't try to use the elevator to unstall, their input was "nose up", see the report.
A much more realistic explanation is http://www.pprune.org/rumours-news/4...ml#post6479529.
Three questions: 1. "Will the pilot be aware that he's in abnormal Law? (and the portents of that)" The answer might well be: "Probably not" (there's nothing to promote awareness of this being the case i.e. no aural annunciation - and thus we arrive at: what now needs to be done that's essential for recovery?)
2. "Does the elevator alone have sufficient authority to unstall the wings at max power or at idle?" The answer is probably not, at least not while the superior trim authority of the THS at 13 degs n/up holds sway.... and particularly not whilst at TOGA power.
3. "Why doesn't the elevator have sufficient authority to unstall?" The whole design premise of the THS is to reduce trim drag and allow the elevator to become more of an active trim and less of a primary flight control. This ideation works well 99.99% of the time and it's used in all models of airliners to some degree. They need the capability of coping with large CofG ranges to accommodate loading, fuel burn-off and configuration changes. Some aircraft augment this capability with tail-located fuel trim-tanks. However this minimalistic elevator design feature in the A330 apparently won't "work" in the progression of events that AF447 underwent.
3. "Why doesn't the elevator have sufficient authority to unstall?" The whole design premise of the THS is to reduce trim drag and allow the elevator to become more of an active trim and less of a primary flight control. This ideation works well 99.99% of the time and it's used in all models of airliners to some degree. They need the capability of coping with large CofG ranges to accommodate loading, fuel burn-off and configuration changes. Some aircraft augment this capability with tail-located fuel trim-tanks. However this minimalistic elevator design feature in the A330 apparently won't "work" in the progression of events that AF447 underwent.
A much more realistic explanation is http://www.pprune.org/rumours-news/4...ml#post6479529.
Perhaps they reacted to windshear, rather than stall.
Full back stick and TOGA, then hold both until the aircraft flies out of the problem.
Full back stick and TOGA, then hold both until the aircraft flies out of the problem.
I know I'll be told that one can't get the sort of low level windshear that demands such aggressive response at altitude, but once the mindset has been made, and all sorts of confusing information is being thrown at one, then I can see the scenario that occurred being played out.
I'm glad I wasn't there.