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AF 447 Thread No. 12

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AF 447 Thread No. 12

Old 2nd Feb 2015, 04:15
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Ian W
The real underlying error I believe is that what has been inadvertently taught to the younger pilots is 'always trust the automation' which is completely the opposite to the more 'experienced' who NEVER fully trust automation.

I do not agree with that statement of yours. Automation if it is not reliable would not have been installed. But a professional pilot has the responsibility to monitor that it is working and experience has nothing to do with it. In SFO experienced pilot was under check and they dropped speed by 30 KTS on approach even the check pilot did not notice it. Thirty three years ago same thing was done this time in A320 in Bangalore India. Thickness of the Log book can hide inadequacies that can develop over a period of time and due to the heavy log book you may not get critically assessed in your refreshers. An important point some pilots are missing out is that whether with automation or without, pilot's scan does not change. In manual flight you scan and make the changes, with auto pilot you scan to ensure it is doing it. This needs to be emphasized in training and not build a mistrust with automation. Mistrust builds fear. How would you do a CAT3 approach if you didn't trust the system? Also you have made some outrageous statements about airbus protections and alternate law etc. clearly indicating that you know very little about them. An automation that is untrustworthy would not have been installed similarly when automation reaches the perfection that it will not need a monitor the pilot,won't he be replaced?
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Old 7th Feb 2015, 02:30
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A question that may have already been answered, and if so, I apologize.

I am not an Airbus pilot, but have some familiarity. I have been informed that there is a display of checklists after a system failure, is this correct? If so, in the case of AF 447, did the system display a checklist or a procedure in any manner following the UAS situation? If not, is there any circumstance when it would? Finally, if it does display such a checklist or procedure, does it advise to turn the FD's off, as most UAS checklists do as a first step? If not, are there circumstances it would display that?

Thank you.
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Old 7th Feb 2015, 07:49
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EXCELLENT LINK ! Thank you Winnerhofer.
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Old 7th Feb 2015, 13:03
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Originally Posted by roulishollandais
EXCELLENT LINK ! Thank you Winnerhofer.
Particularly like the comment on XL-888, the author has clearly discovered and entirely new species of Airbus law - direct law, but with auto-trim and C*. Either that or he hasn't read the XL report or doesn't understand what direct law is, or both.

Shame, as he was doing quite well up to that point...
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Old 7th Feb 2015, 20:02
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seagull967;

1. I have been informed that there is a display of checklists after a system failure, is this correct?
Yes, it is call the "ECAM" - Electronically Centralized Aircraft Monitor". It serves the same purpose as the EICAS on the B767 & B777.

2. If so, in the case of AF 447, did the system display a checklist or a procedure in any manner following the UAS situation?
No. The actual "checklist" is a series of memorized steps to be actioned immediately in response to a loss of airspeed indication. The actual process is, the pilot-flying calls for the drill while continuing to fly the aircraft. The pilot-not-flying actions the memorized items and then the checklist items.

If there is immediate risk to the aircraft, (ie., near to the ground right after takeoff), the memorized drill requires that the autopilot/flight director & autothrust be disconnected, a pitch attitude of 15° be established with TO/GA thrust set, and when at circuit height or minimum safe altitude, to troubleshoot the problem. If at/above higher altitudes, a 5° pitch is set and thrust is placed in the "CLB" detent. In either case, once the memorized items are accomplished by the pilot-not-flying, the paper checklist from the QRH - Quick Reference Handbook - is read and actioned and the aircraft secured for continued flight.

3. If not, is there any circumstance when it would? Finally, if it does display such a checklist or procedure, does it advise to turn the FD's off, as most UAS checklists do as a first step?
Not applicable as you'd see, but the ECAM does display the system losses and checklist items which are actioned and cleared, again using the same process as described above. Turning off the FDs is the first memorized item in the UAS drill.

4. If not, are there circumstances it would display that?
No - turning off the FDs is done in response to drills and/or checklists. Also, if one is not going to follow the FDs, (and there may be legitimate reasons for this), then they must both be turned off.

Last edited by PJ2; 7th Feb 2015 at 21:22.
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Old 8th Feb 2015, 11:22
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Rio by another name

Only if you don't read the report.
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Old 8th Feb 2015, 12:35
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EXCELLENT PART:

And of course if the pilot is unfamiliar with stall recovery and inputs the natural (and absolutely wrong) control back command the situation gets even worse.
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Old 8th Feb 2015, 15:29
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Particularly like the comment on XL-888, the author has clearly discovered and entirely new species of Airbus law - direct law, but with auto-trim and C*. Either that or he hasn't read the XL report or doesn't understand what direct law is, or both.
I think the sarcasm here is a bit harsh. The XL A320 got its stabilizer trim setting in Normal Law (with defective AOA operation). Then at the moment of stall, airflow assymetry caused an ADR problem that dropped them into Direct Law. The aircraft pitched up uncontrollably (without manually running trim down) and finally entered Abnormal Attitude Law when it was too late and the nose too high to recover in the altitude available.
Too bad they didn't drop a wing early on and convert some of that pitch up into turn.
Really too bad they didn't consider the consequences of what might happen if their checks did not go as planned. Didn't even have a minimum airspeed stopping point!!!!
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Old 8th Feb 2015, 16:08
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With regard to the F-GLZU incident of July 2011, it is interesting to see how long it took PF to mentally re-engage with the aircraft.

If t=0 is the time that the overspeed started, here is how it went down:

t=3 seconds, PNF reflexively disengaged AP and pitched up
t=8 seconds PF extended the speedbrakes
t=13 seconds PF retracted the speedbrakes
t=24 seconds PF adjusted his Nav Display ??
t=53 seconds PF surprised to be at FL380
t=1 minute 18 seconds, PF trying to control aircraft thru AP
t=1 minute 42 seconds, PF aware of A/P disengage and at that point appears to be properly engaged with the aircraft.

If this is typical for long range cruise operations, then there is a major problem with the man-machine interface!

At least in this case, the aircraft remained in Normal Law.
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Old 8th Feb 2015, 18:55
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@ MACHINBIRD:

If this is typical for long range cruise operations, then there is a major problem with the man-machine interface
t=3 seconds, PNF reflexively disengaged AP and pitched up
t=8 seconds PF extended the speedbrakes
t=13 seconds PF retracted the speedbrakes
IMO if after these actions BOTH pilots lacks the monitoring of their instruments(Altitude, Airspeed+trend, V/S, Attitude, FMA)
and the lack of CRM after audible warnings accompanied with MW then there is a major problem with the MEN.
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Old 8th Feb 2015, 19:34
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Originally Posted by A33Zab
IMO if after these actions BOTH pilots lacks the monitoring of their instruments(Altitude, Airspeed+trend, V/S, Attitude, FMA)
and the lack of CRM after audible warnings accompanied with MW then there is a major problem with the MEN.
A33Zab, I understand where you are coming from, but it goes deeper than that. The present autoflight interface in cruise allows the pilots to completely mentally disconnect from the process of flying the aircraft. All they have to do is be sure that every few minutes they come back to the big picture of where they are and make sure things are on track.

It is humanly impossible to maintain full mental involvement in the flight process while a computer carries out the real work. After a period of time, the mind drifts elsewhere, despite the best of intentions.

The interface needs to more fully involve the pilots in the flight process. There is no reason that the pilots could not actually fly the aircraft while the computer looks ahead for a possible altitude bust and performs the instructor function to improve pilot skill. How that is best done is up to the software development folks, but I am willing to bet there is a solution.
Might want to swap the PF/PNF functions every 15 minutes or so however.
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Old 8th Feb 2015, 19:44
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Originally Posted by vilas
Earlier stall recovery procedure was based on approach to stall but after a few accidents in the US where the thrust increase prevented the pilot from lowering the nose FAA asked for a review of the procedure.
I don't doubt it but I would still like to know what these "a few accidents in the US" were. I'd appreciate links to reports. In context of old procedure being inadequate, Goldenrivett and Winnerhofer's suggestions that example was G-THOF incident were slightly off mark as:

Originally Posted by AAIB Bulletin 6/2009
The stall recovery techniques recommended
in the manufacturer’s Flight Crew Training
Manual (FCTM) were not fully applied.
...whatever they were at that unenlightened age.

Originally Posted by gums
PLZ convince me that the 'bus control law for pitch is primarily programmed for an attitude versus a gee.
For the umpteenth time: it is not! It holds the flightpath! Not pitch or G!

It's the place in manuals where "needs to know" meets "unable to understand". If Aırbus wrote "maintains vertical flightpath" instead of "maintains 1G corrected for pitch up to 33 deg bank", already high number of confused manual readers would increase even more. So why did Airbus made the system that is so difficult to describe? To make it simple to operate! It works just like the conventional controls with nose following control displacement unless you: hit the protection, stall the aeroplane or have your flight controls disabled. I still haven't found a pilot that would have problems learning or unlearning the sidestick.

Originally Posted by gums
lack of indications that the jet has reached trim l;imits or AoA limits
AoA limits? There is cue on speed display, aural stall warning and strong natural pre-stall buffet.

Originally Posted by gums
My comment about continuing a climb with stick in "neutral" stands.
If initial flightpath is horizontal, it maintains it with stick neutral. If it was descending, it descends with stick neutral. Your point be?

Originally Posted by TC-DCA
So by saying " would try to maintain constant vertical flightpath " we can translate it to try to maintain a pitch the aircraft trim back, true ?
No. If speed changes, it will adjust the pitch to maintain flightpath.

Originally Posted by TC-DCA
I just spoke with an EZY pilot and he told me that there will be normally not a pitch up during a stall in alt. Law and that it´s an requirement of certification by EASA (cs-25) that no abnormal nose up pitching will occur in a stall ?
HTBJ chapter on stick pusher provides enlightenment on how aeroplanes behaving badly were certified way before Airbus.

Originally Posted by His Dudeness
whilst that is true I don´t see the same thing happening on an airplane with 2 interconnected sticks...when the bloody column hits your stomach, you get the message that the other dude is holding it back...
It might clarify the situation if we introduce into discussion BEA's report on AF447 accident, chapter 1.18.6 where cases of holding interconnected yokes into stall are discussed. Meanwhile, there was another sad case of holding the controls fully up till ground impact in Mali.

Originally Posted by Sailvi767
It is worth noting that a Delta Crew encountered the same situation as the AF crew in a 330 on a Pacific flight.
It is also worth noting that out of 36 cases of unreliable airspeeds on 330/340 that preceeded AF447 and were listed in interim 2, 6 happened to AF crews. No damage, no injuries.

Originally Posted by Uplinker
I fly Airbus A330. A lot of what the French captain apparently says is interesting and certainly food for thought - I don't see it as BS, perhaps someone could enlighten me
First, enlightement on BS, from the worlds foremost expert:

Originally Posted by Harry G Frankfurt
It is impossible for someone to lie unless he thinks he knows the truth. Producing
bull**** requires no such conviction. A person who lies is thereby responding to
the truth, and he is to that extent respectful of it. When an honest man speaks, he
says only what he believes to be true; and for the liar, it is correspondingly
indispensable that he considers his statements to be false. For the bull****ter,
however, all these bets are off: he is neither on the side of the true nor on the side
of the false. His eye is not on the facts at all, as the eyes of the honest man and of
the liar are, except insofar as they may be pertinent to his interest in getting away
with what he says. He does not care whether the things he says describe reality
correctly. He just picks them out, or makes them up, to suit his purpose.
Purpose of that certain French capiten was to portray FBW Airbi as dangerous machines. To this end he picked just what suits his agenda, ending up whit statements that might sound true but are either not complete truth or totally meaningless e.g:

FD's are bars helping the pilot to follow his trajectory.
True but not always, especially not at the edge of the envelope, thence BS.

There is a loss of altitude, however marginal this loss ( 350 to 350 ft ) this point is crucial in the understanding of the sequence of events as it explains the crew first move is to pitch up in order to regain the lost altitude (BEA p.179)
It might explain initial climb but not why then the level was severely busted or why climb even after PNF prompts to go down, thence BS.

Joysticks only function is to send inputs to the computer management system which either accepts them or rejects them
True, but worthless without explanation for rejection or that rejections happen very, very seldom or that pitot clogging in AF447 case disabled 'rejectıon' and so FCS tried to deliver pılot's command, thence BS.

(Hence the motto that airbuses cannot stall)
Delivered by who? Weasel words. BS.

45'' after the alarms rang, there have been alternate actions to pitch up and down by the crew
True, but overall pıtch-up actions were of larger displacement and longer duration, omitting this is BS.

Need more?

Originally Posted by Derfred
If Airbus pilots are not trained to regard the aircraft's attitude indicator as their primary instrument, then we have a problem.
There is no other way to fly Airbus. Problem is not that simple, has nothing to do with Airbus and was far better understood by Langewiesche père than fils.

Originally Posted by karnc
When the Bus is messed up, your conventional pilot skill can't help much because when you pull the stick, the plane may not respond by raising up the pitch.
DF Wrong! When it is messed up, it won't stop you from nominating yourself for Darwin Award.

Originally Posted by karnc
I am a sim instructor
Arguments from authority are worthless on anonymous fora.

Originally Posted by PJ2
Fly-by-wire is something like CWS, (Control Wheel Steering) in a Boeing, (but for very different reasons!).
Slight difference being CWS is attitude hold, Airbus is flightpath hold.

Originally Posted by Microburst2002
DIRECT LAW handling characteristics are NOT like a conventional airplane's, no matter what Airbus claims.
I had the pleasure of trying it only in the sim, for about 5-6 hours hands on time and I partially agree; it's not like ATR-42 or Q400; A320 in direct law is far nicer and easier to fly.

Originally Posted by Mıcroburst2002
Sidesticks give no clue of airspeed, like conventional airplane yokes do
Uh-huh. So, the crew of G-THOF got the message from their yokes they are flying too fast? Hey, artificial feeling was pushing hard against their hands, providing tons of feedback.

Originally Posted by Microburst2002
DIRECT law is a very degraded control law (not at all like a reversion to conventional control system). You could never certify an airplane with such system.
FAA disagrees. Maybe your congressman can do something about it?
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Old 8th Feb 2015, 22:22
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It is humanly impossible to maintain full mental involvement in the flight process while a computer carries out the real work. After a period of time, the mind drifts elsewhere, despite the best of intentions.
If even the ATTENTION GETHERS cannot get the attention they require and get them out of 'slumber' mode then I am afraid there is no hope.
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Old 9th Feb 2015, 00:59
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Clandestino;
Slight difference being CWS is attitude hold, Airbus is flightpath hold.
Ack. Was looking for a broad comparison and know the reasons for the difference are nevertheless fundamental. ;-)
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Old 9th Feb 2015, 01:59
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Originally Posted by A33Zab
If even the ATTENTION GETHERS cannot get the attention they require and get them out of 'slumber' mode then I am afraid there is no hope.
If only the main attention getter had been generated ... AP disconnection.

To give priority to a PA over essential stuff is not the best idea ... but how to label a concept that allows a crew to manipulate his flight control command for 6 seconds and as far as 3/4 to stop without being clearly visible to the other crew ?
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Old 9th Feb 2015, 07:53
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CONF iture:

but how to label a concept that allows a crew to manipulate his flight control command for 6 seconds and as far as 3/4 to stop without being clearly visible to the other crew ?
Now that's a good excuse, you forgot to mention the non moving thrust levers.

FCTM 09 Jan 2007:

VMO/MMO EXCEEDANCE

In turbulence, during climb, cruise or descent, the aircraft may slightly exceed
VMO/MMO with the autopilot (AP) engaged.
To prevent such an exceedance, adapt speed or Mach target.
If severe turbulence is known or forecasted, consider the use of turbulence speed.
If the current speed is close to the VMO (maximum operating speed), monitor
the speed trend symbol on the PFD.
If the speed trend reaches, or slightly exceeds, the VMO limit:
. Use the FCU immediately to select a lower speed target.
If the speed trend significantly exceeds the VMO red band, without high speed
protection activation:
. Select a lower target speed on the FCU and, if the aircraft continues to
accelerate, consider disconnecting the AP.
. Before re-engaging the AP, smoothly establish a shallower pitch attitude.

If the aircraft accelerates above VMO with the AP engaged, the AP will disengage
on reaching the high speed protection. The high speed protection will apply a
nose-up order up to 1.75 g, in addition to pilot input during VMO recovery.
Therefore, make a smooth pitch correction in order to recover proper speed.
Speedbrakes may be used in case of high speed exceedance, but the flight crew
should be aware of pitch influence. In addition, speedbrakes will be used with
caution, close to the ceiling.
High Speed Protection may also result in activation of the angle of attack
protection.
In all events, check the AP engagement status, and re-engage it when
appropriate. It may have tripped and the associated aural warning may have
been superseded by the overspeed aural warning.

Last edited by A33Zab; 9th Feb 2015 at 09:30.
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Old 9th Feb 2015, 12:29
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Originally Posted by A33Zab
Now that's a good excuse
Not an excuse, merely a characteristic of the Airbus concept that allows one crew member to manipulate his flight control command with large amplitude and for consequent period of time without the other crew members being able to directly seeing those inputs. The 310 was the last one in Toulouse to not suppress such interesting first hand data.
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Old 9th Feb 2015, 12:52
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Originally Posted by Machinbird
I think the sarcasm here is a bit harsh. The XL A320 got its stabilizer trim setting in Normal Law (with defective AOA operation). Then at the moment of stall, airflow assymetry caused an ADR problem that dropped them into Direct Law. The aircraft pitched up uncontrollably (without manually running trim down) and finally entered Abnormal Attitude Law when it was too late and the nose too high to recover in the altitude available.
Exactly - and that is why it has precisely nothing to do with a supposed design issue with C* in stall - they were not in C* in stall.

Nor is the trim up a C* or bus issue - it will happen exactly the same on a conventional, depending on AP mode, if speed is allowed to decay. I think XL is closer to G-THOF (a 737, thats how much C* has to do with it) than to AF447 - both crews had difficulty recovering due to being out of trim, both crews omitted to trim, G-THOF ended better only because they reduced thrust to get elevator authority back.

If XL (and G-THOF) illustrate any design flaw it is with underslung engines, not C* - but in my opinion every design decision has compromises, no design is perfect in every scenario, and what it really illustrates is the perils of trying to recover a pitch upset by adding thrust when your thrust line is below COG.
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Old 9th Feb 2015, 14:16
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Amber to Red.

The ECAM message AP OFF that comes on after pushing the take-over button is coloured red not amber, as in the report.

A very well written report that brings out many good points and traps.
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Old 9th Feb 2015, 14:45
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Originally Posted by Clandestino
For the umpteenth time: it is not! It holds the flightpath! Not pitch or G! It's the place in manuals where "needs to know" meets "unable to understand". If Aırbus wrote "maintains vertical flightpath" instead of "maintains 1G corrected for pitch up to 33 deg bank", already high number of confused manual readers would increase even more.
That is no excuse for writing an ops or a training manual that doesn't educate as well as train. You have to know how your system works to operate it professionally.
So why did Airbus made the system that is so difficult to describe? To make it simple to operate!
Actually, your sentence makes sense if you omit "that is so difficult to describe." As above, there is no excuse for not taking the effort to describe it clearly to the operators. You are carrying the trusting public in your aluminum tubes with wings.
AoA limits? There is cue on speed display, aural stall warning and strong natural pre-stall buffet.
Since we are discussing AF 447, we may wish to remember that in this case airspeed indications had gone on holiday thanks to a voting procedure. (And some ice in the tubes). Granted, that eventually resolved itself but by then the crew were behind the aircraft.
HTBJ chapter on stick pusher provides enlightenment on how aeroplanes behaving badly were certified way before Airbus.
A point worth remembering.
Meanwhile, there was another sad case of holding the controls fully up till ground impact in Mali.
Lesson: there is no collective experience, there is no collective memory. A given crew only has its experience, memory, professional education, and professional training.
It is also worth noting that out of 36 cases of unreliable airspeeds on 330/340 that preceeded AF447 and were listed in interim 2, 6 happened to AF crews. No damage, no injuries.
Indeed worth noting.
It might explain initial climb but not why then the level was severely busted or why climb even after PNF prompts to go down, thence BS.
So what does explain that, in your humble opinion?
FAA disagrees. Maybe your congressman can do something about it?
Not if he knows what's good for his wallet.
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