Airbus crash/training flight
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Most of that 25 seconds were spent in Abnormal Attitude law, with no Autotrim.
The plane was trimmed out of pitch control range, and not by the pilots, how can you seriously claim it's the pilot's fault ?
Safety Concerns:
Exactly what I wanted to know when I asked earlier, and never got an answer to, is if there is an AoA readout in the cockpit. Before driving an airplane into a situation where accurate AoA input is essential to control of the aircraft, we should be confident that at least one of the three AoA sensors is providing good data. From your question, I must assume that there is no way to adequately assess that aspect of the congtrol system. I suggest that there should be and it should be part of the preparation for that kind of test.
Hardcore hits a home run when he says:
So how exactly ed do you determine which from the 3 serviceable systems are u/s?
Hardcore hits a home run when he says:
Can we point the finger at the pilots as the sole cause? Maybe! Do we lose the chance to isolate and identify an inherent systemic flaw. Yes
CONF iture;
No, SFLY is not correct and the situations you cite, while possible, are unlikely but none of us will know until the final report.
Regarding the Pitch Trim Wheels, the FCOM states that:
From the FCOM:
ABNORMAL ATTITUDE LAWS
The system applies an abnormal-attitude law in pitch and roll if the aircraft exceeds any of these limits in flight.
Pitch attitude > 50° nose up or 30° nose down
Bank angle > 125°
Angle of attack > 30° or < − 10° (− 15° for A319 and A321)
Speed > 440 knots or < 60 knots
Mach > 0.91 or < 0.1
The law in pitch is the alternate law with no protection except load-factor protection and without auto trim.
In roll it is a full-authority direct law with a yaw mechanical.
When the aircraft has recovered from its abnormal attitude, the flight control laws in effect are :
in pitch : alternate law without protection with autotrim.
in roll : full authority direct law with yaw alternate law.
There is no reversion to the direct law when the pilot extends the landing gear.
From the Interim Report:
At 15 h 45 min 29 s, landing gear retraction was ordered.
At 15 h 45 min 36 s, the stall warning sounded again.
At 15 h 45 min 40 s, the control law for pitch passed from direct to alternate. The bank angle reached a maximum of 59° to the left and the normal load factor dropped below 0.5 g. TheCaptains lateral input is practically at neutral, the longitudinal input is still forwards but is not constantly at the stop. The yaw damper orders were nil and remained so until the end of the flight.
At 15 h 45 min 44 s, the altitude reached a maximum of about 3,800 ft and pitch reached 57° nose up. The bank angle was about 40° to the left.
Although in alternate law 25 seconds before the end of the flight, autotrim (in pitch) may not have been available due to the 57deg pitch attitude at 15h 45m 44s, and loss of autotrim in Abnormal Attitude Laws. As the FCOM states, manual pitch trim is always available and takes priority over electrical control. Manual intervention on the THS was possible at all times, the possibility of the THS being jammed, notwithstanding.
Regarding being able to either view the FMA well enough to see the messages, (dusk, no sun in eyes at high pitch angle, etc), or the notion that the display is somehow "decluttered", I am not aware of such a process where it concerns either messages associated with manual pitch trim - both the amber and the red manual pitch trim messages on the PFD are clear and unmistakable. It would be of some interest to know whether the recorders actually record this message and if so, whether it was present or not.
SC is correct. This was a human error accident on a number of levels including, as I observed, planning and execution similarities to the Toulouse A330 accident.
DC-ATE;
You said:
Cover-up? That's going a bit far isn't it?
PJ2, I believe SFLY is correct :
25 seconds before the end, the pitch was back in alternate law, but the stabilizer position did not move (?)
There is a possibility that the stabilizer was jammed (?)
There is a possibility that the pilot tried earlier to move it with no more success than the automatic system (?)
25 seconds before the end, the pitch was back in alternate law, but the stabilizer position did not move (?)
There is a possibility that the stabilizer was jammed (?)
There is a possibility that the pilot tried earlier to move it with no more success than the automatic system (?)
Regarding the Pitch Trim Wheels, the FCOM states that:
Both pitch trim wheels provide mechanical control of the THS and have priority over electrical control.
A pilot action on the pitch trim wheel disconnects the autopilot.
From the FCOM:
ABNORMAL ATTITUDE LAWS
The system applies an abnormal-attitude law in pitch and roll if the aircraft exceeds any of these limits in flight.
Pitch attitude > 50° nose up or 30° nose down
Bank angle > 125°
Angle of attack > 30° or < − 10° (− 15° for A319 and A321)
Speed > 440 knots or < 60 knots
Mach > 0.91 or < 0.1
The law in pitch is the alternate law with no protection except load-factor protection and without auto trim.
In roll it is a full-authority direct law with a yaw mechanical.
When the aircraft has recovered from its abnormal attitude, the flight control laws in effect are :
in pitch : alternate law without protection with autotrim.
in roll : full authority direct law with yaw alternate law.
There is no reversion to the direct law when the pilot extends the landing gear.
From the Interim Report:
At 15 h 45 min 29 s, landing gear retraction was ordered.
At 15 h 45 min 36 s, the stall warning sounded again.
At 15 h 45 min 40 s, the control law for pitch passed from direct to alternate. The bank angle reached a maximum of 59° to the left and the normal load factor dropped below 0.5 g. TheCaptains lateral input is practically at neutral, the longitudinal input is still forwards but is not constantly at the stop. The yaw damper orders were nil and remained so until the end of the flight.
At 15 h 45 min 44 s, the altitude reached a maximum of about 3,800 ft and pitch reached 57° nose up. The bank angle was about 40° to the left.
Although in alternate law 25 seconds before the end of the flight, autotrim (in pitch) may not have been available due to the 57deg pitch attitude at 15h 45m 44s, and loss of autotrim in Abnormal Attitude Laws. As the FCOM states, manual pitch trim is always available and takes priority over electrical control. Manual intervention on the THS was possible at all times, the possibility of the THS being jammed, notwithstanding.
Regarding being able to either view the FMA well enough to see the messages, (dusk, no sun in eyes at high pitch angle, etc), or the notion that the display is somehow "decluttered", I am not aware of such a process where it concerns either messages associated with manual pitch trim - both the amber and the red manual pitch trim messages on the PFD are clear and unmistakable. It would be of some interest to know whether the recorders actually record this message and if so, whether it was present or not.
SC is correct. This was a human error accident on a number of levels including, as I observed, planning and execution similarities to the Toulouse A330 accident.
DC-ATE;
You said:
. . . as I told Smilin_Ed, I think we're beating a 'dead horse' here. History will tell all.....if not covered up. Let these boys play with their toys and hopefully everyone will get where they're going safely.
Last edited by PJ2; 1st Mar 2009 at 16:01.
Flight Safety:
No one here is denying that there was pilot/crew error. No one here is denying that faulty sensor (AoA or other) cannot affect the flying qualities of non-FBW aircraft. What I am saying, and I think at least some others agree, is that there was a hardware, software, or training/experience problem which aggravated the situation and inhibited the pilots' ability to recover from it. That problem, or problems, need to be aired and everyone will benefit from that. Sweeping problems under the rug benefits no one.
No one here is denying that there was pilot/crew error. No one here is denying that faulty sensor (AoA or other) cannot affect the flying qualities of non-FBW aircraft. What I am saying, and I think at least some others agree, is that there was a hardware, software, or training/experience problem which aggravated the situation and inhibited the pilots' ability to recover from it. That problem, or problems, need to be aired and everyone will benefit from that. Sweeping problems under the rug benefits no one.
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airfoilmod do you actually know what has happened here?
are you sure you have been following events?
I will make it simple as I did in post #682
There is no magic to it. You just need to read understand and quit with your biased outdated opinions. You are out of touch. Sorry but it has to be said
are you sure you have been following events?
I will make it simple as I did in post #682
this thread has got ridiculous. So AOA sensors painted over and stuck in one position (human error). A/C stalled and crew performed actions as any crew would do on any aircraft, digital or analogue but it was sadly too late because they hadn't allowed height for recovery (human error).
Now change the bloody boeing v airbus record
Now change the bloody boeing v airbus record
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Thank You
And that's the point you want to miss. FBW couldn't handle a little poly-urethane in a little hole (s). Like the B-2 that was programmed wet by ground crew and went in with a ridiculous deck angle, because electrons don't think, and when no allowance (training or disconnect) is available to the handling pilot, he's along for the very expensive and life-ending final flight. Got it?
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As Finn47 suggested a long time back in this thread, it is not entirely fair to compare accident rate of A320/330/340 with the 737.
In the first place 737 is "all series", so you are including some pretty ratty 1968 200's being operated in Africa & S America. Secondly, A320 has benefited from many other safety enhancement like EGPWS , TCAS etc which didn't exist for the first decade or two of the 737's in service life.
When all is said & done, I doubt if you compared A320/319/318/321 with 737NG ( the fairest comparison as A340/330 are of course making longer sectors hence less T/O & Ldg . . the dodgy bit, & the NG is in more "reputable" hands ) I doubt if the Airbii will be any safer, merely having different types of accidents - or at least for subtly different reasons.
More than one way to skin a cat I know, but I would rather pull 3g if I found myself pointing vertically at the Med at 1500ft & give the airframe to the EAS dinosaur collection after it's unplanned final flight (already they have plenty ) than become fish food.
Sorry but that is my take on it.
Side sticks & thrust levers that don't move ? no thanks , at least Boeing seem to have learned from Airbus's mistakes ( Oh yes mistakes, make no mistake of that ) when deciding what tactile feedback should be offered on the 777, at least some common sense prevailed there.
In the first place 737 is "all series", so you are including some pretty ratty 1968 200's being operated in Africa & S America. Secondly, A320 has benefited from many other safety enhancement like EGPWS , TCAS etc which didn't exist for the first decade or two of the 737's in service life.
When all is said & done, I doubt if you compared A320/319/318/321 with 737NG ( the fairest comparison as A340/330 are of course making longer sectors hence less T/O & Ldg . . the dodgy bit, & the NG is in more "reputable" hands ) I doubt if the Airbii will be any safer, merely having different types of accidents - or at least for subtly different reasons.
More than one way to skin a cat I know, but I would rather pull 3g if I found myself pointing vertically at the Med at 1500ft & give the airframe to the EAS dinosaur collection after it's unplanned final flight (already they have plenty ) than become fish food.
Sorry but that is my take on it.
Side sticks & thrust levers that don't move ? no thanks , at least Boeing seem to have learned from Airbus's mistakes ( Oh yes mistakes, make no mistake of that ) when deciding what tactile feedback should be offered on the 777, at least some common sense prevailed there.
airfoilmod;
If I may...
Clearly electrons don't "think" but neither do hydraulic fluid or cables/pulleys. The method by which control is executed is less important than the interventions available to the crew. I think most are agreed on this.
The intervention available to this crew was manual pitch through the THS Wheel on the pedestal. While we do not know yet whether the amber message, "Use Manual Pitch Trim" was actually displayed, it is whenever the airplane is in Direct Law. Regardless, the THS manual input is always available in Normal Law/Alternate Law. Clearly, the design concept behind elevator authority could not be expected to extend to 57deg NU pitch attitude. No transport category aircraft does this - the aircraft is out of control at this stage of flight and beyond test-pilot territory, from which recovery may or may not be possible.
I think had the THS wheel been aggressively moved towards ND, there is a possibility that the aircraft may have recovered but that is pure conjecture. The secondary stall may or may not have been prevented.
What is not conjecture is the behaviour of the airplane. In the circumstances and regimes this aircraft was placed in at the altitude it was, without timely and aggressive intervention, no transport category aircraft would have survived.
The suggestion that an approach-to-stall manoeuvre be carried out at low altitude, (3000ft ASL, approx), in Config FULL/gear down, with no prior briefings as to crew actions before/during/post test, indications to be expected, etc including an "in case of...", was made, contrary to the SA CAM (Single Aisle Customer Acceptance Manual) developed by Airbus for this manoeuvre/test.
I do not believe any of the above was heard briefed on the CVR but we haven't heard the entire record yet.
PJ2
FBW couldn't handle a little poly-urethane in a little hole (s). Like the B-2 that was programmed wet by ground crew and went in with a ridiculous deck angle, because electrons don't think, and when no allowance (training or disconnect) is available to the handling pilot, he's along for the very expensive and life-ending final flight. Got it?
Clearly electrons don't "think" but neither do hydraulic fluid or cables/pulleys. The method by which control is executed is less important than the interventions available to the crew. I think most are agreed on this.
The intervention available to this crew was manual pitch through the THS Wheel on the pedestal. While we do not know yet whether the amber message, "Use Manual Pitch Trim" was actually displayed, it is whenever the airplane is in Direct Law. Regardless, the THS manual input is always available in Normal Law/Alternate Law. Clearly, the design concept behind elevator authority could not be expected to extend to 57deg NU pitch attitude. No transport category aircraft does this - the aircraft is out of control at this stage of flight and beyond test-pilot territory, from which recovery may or may not be possible.
I think had the THS wheel been aggressively moved towards ND, there is a possibility that the aircraft may have recovered but that is pure conjecture. The secondary stall may or may not have been prevented.
What is not conjecture is the behaviour of the airplane. In the circumstances and regimes this aircraft was placed in at the altitude it was, without timely and aggressive intervention, no transport category aircraft would have survived.
The suggestion that an approach-to-stall manoeuvre be carried out at low altitude, (3000ft ASL, approx), in Config FULL/gear down, with no prior briefings as to crew actions before/during/post test, indications to be expected, etc including an "in case of...", was made, contrary to the SA CAM (Single Aisle Customer Acceptance Manual) developed by Airbus for this manoeuvre/test.
The captain even indicated reluctance to execute the manoeuvre. From the Interim Report:
While the co-pilot was reading back, the Captain indicated to the New Zealand pilot that the low speed flight should be made later, during the flight towards Frankfurt. He even considered not performing it.
It is hard to say how the ELACs/SECs/FACs were responding in terms of time -the rapid changes in pitch and roll may or may not have passed the aircraft into the Abnormal Attitudes Laws due to 57deg NU pitch, followed by 42deg ND. Autotrim is not available in these regimes but manual (cable, actually), always is available to the crew. That fact is no different than any other transport category aircraft in the sense, once again, that the engineers will not consider 57deg NU, "normal flight" nor will the certification authorities require (as per earlier posts) "auto..." response from the flight controls when the aircraft itself is out of control.
From the Interim Report, regarding flight in low speed regime. My bolding:
1.17.3 Flight at low speed FULL configuration
he flight at low speed described in the SA CAM consists of checking the activation of the angle of attack protections in normal law and FULL configuration. The flight at low speed as described in the OFC document is identical but does not include going as far as the check on the alpha max protection.
The check is supposed to be performed at about FL140. The crew must adjust the thrust in order to maintain the speed at VLS. When the speed is stable, they should place the thrust levers in the IDLE position and manage the airplanes pitch attitude so as to obtain a rate of deceleration of one knot per second. During the deceleration, they should observe auto-trim disconnect (activation of alpha prot) then activation of the alpha floor function. This function should then be de-activated.
At a weight of 53.7 tons at the time of the check, the OFC document indicates a VLS speed of 123 knots and a minimum speed of 107 knots.
N.B.: the speeds indicated by the SA CAM document depend on the type of engines. The speed reference in the OFC document corresponds to CFM engines but the speeds indicated are in conformity with the speeds in the SA CAM manual for IAE engines. In the ISATM manual, the flight at low speed is described in more detail. It should be performed first in clean configuration and it is specifically required to compare the three AOA values before performing the flight at low speed in FULL configuration.
he flight at low speed described in the SA CAM consists of checking the activation of the angle of attack protections in normal law and FULL configuration. The flight at low speed as described in the OFC document is identical but does not include going as far as the check on the alpha max protection.
The check is supposed to be performed at about FL140. The crew must adjust the thrust in order to maintain the speed at VLS. When the speed is stable, they should place the thrust levers in the IDLE position and manage the airplanes pitch attitude so as to obtain a rate of deceleration of one knot per second. During the deceleration, they should observe auto-trim disconnect (activation of alpha prot) then activation of the alpha floor function. This function should then be de-activated.
At a weight of 53.7 tons at the time of the check, the OFC document indicates a VLS speed of 123 knots and a minimum speed of 107 knots.
N.B.: the speeds indicated by the SA CAM document depend on the type of engines. The speed reference in the OFC document corresponds to CFM engines but the speeds indicated are in conformity with the speeds in the SA CAM manual for IAE engines. In the ISATM manual, the flight at low speed is described in more detail. It should be performed first in clean configuration and it is specifically required to compare the three AOA values before performing the flight at low speed in FULL configuration.
PJ2
Last edited by PJ2; 1st Mar 2009 at 21:24.
I find it difficult to comprehend how anyone can defute 'human error' when this demanding profile was flown:
All this "Well heck, the good-ole DC-3 didn't behave like that" comment is utterly irrelevant. When a specific schedule is written, it absolutely must be adhered to - just read how ego destroyed a perfectly serviceable aircraft in the account of 'Big head' Yeager's accident in the NF-104.....
Today's flight test pilots should learn from history, but not be totally constrained by it. But they must be very familiar with the aircraft, have sufficient training and skill for the required task and not be afraid to reject commercial influence.
The aeroplane with the most complicated flight control system I've flown was the Folland Gnat; it would happily kill you if you didn't understand the system, stay within the associated limitations and have an instinctive knowledge of system failure drills. Even a pilot as clumsy and hamfisted as I was managed to cope with that! Fortunately, most large aircraft have far greater systems redundancy, but my Gnat training taught me that any flight test pilot MUST be familiar with the aircraft and the flight test procedure and must stick rigidly to the test requirements.
It is already abundantly clear that this crew didn't.
The reasons why have yet to be ascertained though.
- By a crew who had received no training for this type of flight.
- Outside the test point for the specific test
- In a distracting ATC environment
- Subject to time and commercial pressures
All this "Well heck, the good-ole DC-3 didn't behave like that" comment is utterly irrelevant. When a specific schedule is written, it absolutely must be adhered to - just read how ego destroyed a perfectly serviceable aircraft in the account of 'Big head' Yeager's accident in the NF-104.....
Chuck reminded me of the racecar drivers of long ago versus todays drivers. The old ones just felt it and drove it. The great current drivers help to establish the design, understand the technology and why the car handles like it does and grow with changes. Some of the best are engineering graduates.
The aeroplane with the most complicated flight control system I've flown was the Folland Gnat; it would happily kill you if you didn't understand the system, stay within the associated limitations and have an instinctive knowledge of system failure drills. Even a pilot as clumsy and hamfisted as I was managed to cope with that! Fortunately, most large aircraft have far greater systems redundancy, but my Gnat training taught me that any flight test pilot MUST be familiar with the aircraft and the flight test procedure and must stick rigidly to the test requirements.
It is already abundantly clear that this crew didn't.
The reasons why have yet to be ascertained though.
BEagle;
Re,
Well, precisely. Those were two points which, though again obvious in the Interim Report, I thought too much to bring into the discourse all at once but both are mentioned in the Report as factors at work within the overall command-and-control and planning environment.
Re,
In a distracting ATC environment
Subject to time and commercial pressures
Subject to time and commercial pressures
No matter what term the overpaid aviation trick-cyclists might invent next for some fluffed-up 'safety programme', such as 'Crew Resource Management' or 'Threat and Error Management', the only thing which will really stop pilots getting themselves into this sort of situation in future is Basic airmanship!!
But that requires experience. Which these days cost a lot of money.
It is quite clear that distraction was a key ingredient in this accident.
But that requires experience. Which these days cost a lot of money.
It is quite clear that distraction was a key ingredient in this accident.
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S.F.L.Y. you asked
Nobody told me, I worked it out using the FDR readout and FCOM 1. If > 50° NU pitch, or > 30°ND pitch, or below 60kt, Abnormal Attitude law applies, which is Alternate Law in pitch with no autotrim. If you examine the readouts you will see that abnormal Attitude law would have applied for all but 5 or 6 seconds of the last 26.
The 2500ft 120 Kias level-off (your words) occurred at about 15:45:23 with the a/c in Direct law - so any movement of the THS would be done manually by the pilot. I do not know why the THS did not move - perhaps the CVR will tell us.
The HYD system page was displayed on ECAM at 15:45:48 - during the ultra-low-speed period - which may indicate that the crew were checking for HYD problems affecting the THS. Again perhaps the CVR etc...
CONF asked
I think if you compare the Captain's sidestick position in roll(direct) and the aileron deflection the two match perfectly; in pitch Direct phase the sidestick and elevator position match; when back in alternate law in pitch at about 15:45:50 there is a period of full up elevator which does not match... but that will happen in that control law by design.
TP
Who told you no auto trim ? The plane was in Alt law and most of these 20s were with forward stick. Why then the ths didn't show any sign of movement toward the -5 setting matching with the 2500ft 120 Kias level-off ?
The 2500ft 120 Kias level-off (your words) occurred at about 15:45:23 with the a/c in Direct law - so any movement of the THS would be done manually by the pilot. I do not know why the THS did not move - perhaps the CVR will tell us.
The HYD system page was displayed on ECAM at 15:45:48 - during the ultra-low-speed period - which may indicate that the crew were checking for HYD problems affecting the THS. Again perhaps the CVR etc...
CONF asked
Where are the graphs for the FO side stick position ?
TP
Last edited by TyroPicard; 1st Mar 2009 at 20:20.
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when back in alternate law in pitch at about 15:45:50 there is a period of full up elevator which does not match... but that will happen in that control law by design
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The 2500ft 120 Kias level-off (your words) occurred at about 15:45:23 with the a/c in Direct law
Hi ,
The following is part of the report for QF72 pitch down event.
I don't know much about Airbus systems and was wondering if one of you folk who are expert in this area could shine some light on why these two events are not related. The similarity I see is the AOA values spiking.
I know they are different machines but are there common parts/equipment in the AOA or FAC systems?
I apologise if the observation is too simplistic.
Framer
The following is part of the report for QF72 pitch down event.
I don't know much about Airbus systems and was wondering if one of you folk who are expert in this area could shine some light on why these two events are not related. The similarity I see is the AOA values spiking.
I know they are different machines but are there common parts/equipment in the AOA or FAC systems?
I apologise if the observation is too simplistic.
Framer
. In cruise, a typical AOA is +2 degrees.
The first AOA Left spike19 occurred at 0440:34 UTC. AOA Left values changed from +2.1 degrees to +50.6 degrees and back to +2.1 degrees over three successive samples. Forty-two AOA Left spikes were recorded before the aircraft touched down at Learmonth. As AOA Left is sampled once per second, a spike may not necessarily be sampled and recorded. As a result, the number of actual AOA Left spikes may have been larger than the number recorded.
Spikes were also evident in the following parameters:
pressure altitude
computed airspeed
mach number
static air temperature
pitch angle
roll angle
wind speed
wind direction.
Effects of the spikes on failure indications
A stall warning parameter was recorded by the FDR. The first stall warning occurred at 0440:50 UTC and numerous stall warnings were recorded from this time until 0512:00 UTC when the aircraft was descending through an altitude of 12,400 ft.
The first AOA Left spike19 occurred at 0440:34 UTC. AOA Left values changed from +2.1 degrees to +50.6 degrees and back to +2.1 degrees over three successive samples. Forty-two AOA Left spikes were recorded before the aircraft touched down at Learmonth. As AOA Left is sampled once per second, a spike may not necessarily be sampled and recorded. As a result, the number of actual AOA Left spikes may have been larger than the number recorded.
Spikes were also evident in the following parameters:
pressure altitude
computed airspeed
mach number
static air temperature
pitch angle
roll angle
wind speed
wind direction.
Effects of the spikes on failure indications
A stall warning parameter was recorded by the FDR. The first stall warning occurred at 0440:50 UTC and numerous stall warnings were recorded from this time until 0512:00 UTC when the aircraft was descending through an altitude of 12,400 ft.
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S.F.L.Y. wrote
OK I'm with you now...
15:45:50 CAS is 40kt - Abnormal attitude law, no autotrim.
15:45:52 CAS >60kt - back to Alternate law, autotrim enabled.
15:45:55 CAS 120kt pitch zero or slightly less - now blow up the readout and look at the altitude - from the slope of the graph I estimate the V/S at 4,000'/min down... not quite a level-off! And we do not have the flap/slat position readout which is very relevant.
But if you look at the next graph below the sidestick readout you will see both elevators fully up at 15:45:50 - which is what TyroPicard actually saw.
Please don't put words into my mouth.
I tend to deal in facts - I can't explain it because I don't have all the facts. What I do know is that when a control law change occurs it takes a few seconds for ECAM to inform the crew.
15:45:52 the stall warning occurred again
15:45:58 pitch >30°ND so back to Abnormal attitude law, no autotrim.
A total of 6 seconds approx with autotrim enabled.
I am not aware of anyone posting that. As I said before "perhaps the CVR etc.."
and for CONF
I wrote
I probably should have said "may" not "will". In pitch load factor demand law (Normal,Alternate) the sidestick and elevator positions are not directly connected. If you fly stick neutral the ELAC moves the elevator to maintain 1g. Imagine a jammed THS and change the thrust/speed/config, if stick neutral the elevator will move to maintain 1g - invisible to the pilot unless you display F/CTL system on ECAM.
Without the F/O sidestick readout, the actual load factor demanded and achieved, it is impossible to be certain why the elevator is in that position. Hope that's clearer.
Regards, TP
This is absolutely wrong: it was at 15:45:50 and in alternate law. At that point, the pitch had stopped dropping, wings were horizontal and IAS was 120 at 2500ft.
15:45:50 CAS is 40kt - Abnormal attitude law, no autotrim.
15:45:52 CAS >60kt - back to Alternate law, autotrim enabled.
15:45:55 CAS 120kt pitch zero or slightly less - now blow up the readout and look at the altitude - from the slope of the graph I estimate the V/S at 4,000'/min down... not quite a level-off! And we do not have the flap/slat position readout which is very relevant.
You can even see fully forward stick (which is what Tyropicard probably designated as full up elevator)
Please don't put words into my mouth.
At that time there was no unusual attitude, alternate law and full forward stick: in other words the auto trim should have shown a signe of movement. How do you explain that ?
15:45:52 the stall warning occurred again
15:45:58 pitch >30°ND so back to Abnormal attitude law, no autotrim.
A total of 6 seconds approx with autotrim enabled.
How can anybody say the crew didn't try to use manual trim?
and for CONF
I wrote
when back in alternate law in pitch at about 15:45:50 there is a period of full up elevator which does not match... but that will happen in that control law by design
TyroPicard, would you develop that point for me please.
Without the F/O sidestick readout, the actual load factor demanded and achieved, it is impossible to be certain why the elevator is in that position. Hope that's clearer.
Regards, TP
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framer
Are you referring to the Perpignan AOA on Takeoff and initial climb? That looks normal to me though I have not given it careful analysis, and the scale is too small to observe any anomalies.
There is an AOA "hump" at about 15:03:00 which matches a CAS variation exactly - after that the AOA values become fixed.
I don't see any "spikes".
TP
Are you referring to the Perpignan AOA on Takeoff and initial climb? That looks normal to me though I have not given it careful analysis, and the scale is too small to observe any anomalies.
There is an AOA "hump" at about 15:03:00 which matches a CAS variation exactly - after that the AOA values become fixed.
I don't see any "spikes".
TP
yeah Tyro, good point, they are frozen and not spiking. I guess I was just trying to see if it was something as simple as a bad batch of computer components or similar. Very simplistic I admit.
Framer
Framer