AF 447 report out
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This is, I think, a question that was never answered.
As Mac the Knife's translation shows, it says that EASA failed in its duty of assessing airworthiness of aircraft under its juridiction.
Sadly, it remind me of the FAA and the 787 certification (batteries...)
Could agencies do their job? They seems to have neither the competences nor the will (or power, budget...) to do so. Meanwhile, the aircraft become more complex...
Systemic issue?
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AZR:
Is that an "Airbus" design or an "Industry" design, i.e. same situation or comparable airliners (Boeings, Bombardier, Embraer...) ?
This is, I think, a question that was never answered.
This is, I think, a question that was never answered.
ADIRU ARINC Air data output is set to AoA NCD(No Computed Data) to the subsystems (e.g. FWC) at 60 kt or less and air speed output NCD below 30 kt or less.
IIRC Boeing T7 ADIRU sets NCD <30Kt and SAARU <50 kt-
"Airbus" design offered several options like analog AoA indicators and/or BUSS (AoA output thru IR part of ADIRU i.s.o. Air Data part).
It is up to the operator(pilots?) to select such an option or not!
Link to AF BUSS
Last edited by A33Zab; 17th May 2013 at 12:00. Reason: added link
Through incompetence they flew a plane into a stall then into the Atlantic.
on this thread is simply a distraction from the core issue.They had a problem. They didn't follow the QRH. They killed their passengers and themselves....
Perhaps a little emotive or tactless to word that last sentence so, for they were not willful acts of negligence.
would ' which incompetence was the root cause of this horrific disaster' be an improvement?
would ' which incompetence was the root cause of this horrific disaster' be an improvement?
Last edited by Fantome; 17th May 2013 at 19:36.
Dog Tired
They didn't follow the QRH
QRHs were around about 1969-72 for me (Hunter then F4). Airbus aircraft are a lot more sophisticated and, as you are doubtless aware, are not used these days.
Am I the first to admit I would have been severely challenged and, probably, overcome by the situation?
Mind you, I have only twenty years Airbus and extensive examiner experience.
What, in your opinion, is the core issue?
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QRHs were around about 1969-72 for me (Hunter then F4). Airbus aircraft are a lot more sophisticated and, as you are doubtless aware, are not used these days.
On the A330, the ECAM proposes actions to be carried out in the majority of failure or emergency cases. From the information available on the ECAM, the crew must analyse and confirm the type of failure before undertaking any failure processing action. In other cases, the “adequate reaction” expected of the crew supposes immediate memory items with the purpose of stabilising the situation, then recourse to action instructions available on the ECAM, and/or recourse to procedures explained in the QRH and classified by category of diagnosed anomaly.
The lesson I take home from all this is that very complex systems generate very complex and confusing failure modes that software engineers and designers cannot possibly discover.
This means that:
1. Automation must never be totally trusted.
2. It must be possible for the crew to revert to basic mechanical instruments and hand fly the aircraft from first principles.
3. Modifications and upgrades are going to become a nightmare for Airbus because it is impossible to completely understand if new failure modes have been created.
I make exception for the basic fly by wire automatics, but nothing else, and if you are going to use side sticks they had better have a mechanical connection so it is patently obvious to blind freddy what control inputs are being applied.
I expect more of these type of accidents.
This means that:
1. Automation must never be totally trusted.
2. It must be possible for the crew to revert to basic mechanical instruments and hand fly the aircraft from first principles.
3. Modifications and upgrades are going to become a nightmare for Airbus because it is impossible to completely understand if new failure modes have been created.
I make exception for the basic fly by wire automatics, but nothing else, and if you are going to use side sticks they had better have a mechanical connection so it is patently obvious to blind freddy what control inputs are being applied.
I expect more of these type of accidents.
I expect more of these type of accidents.
or stop calling them pilots - Digital Device Programmed Anomaly Corrective Operatives - seems more appropriate these days. Pilots fly aeroplanes.
I recall a cartoon in Punch, after the first, much publicised, auto-land event, drawn by a very well known Punch cartoonist - so well known that I've forgotten his name ! - it showed a uniformed pilot in a glass cage at the back of the flight deck, with a hammer hanging on the front bearing the notice " In Case of Emergency Break the Glass "
'course - the decision than would be when to break the glass - or call the Captain back from the bunk ?
Last edited by ExSp33db1rd; 17th May 2013 at 21:49.
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NB : This post is intended as summary only - as PJ2 says, the arguments were exhaustively played out over 11 threads in Tech Log.
@Sunfish - This was not a complex or unforeseen failure mode. Unreliable Airspeed Indication causes a drop to Alternate Law, which has no hard protections. This was well-understood by all the engineers, and if it was not communicated to line pilots, it should have been. We know Airbus sent out a bulletin describing a workaround procedure while the problematic pitot tubes were being replaced. How well this was disseminated by airlines amongst their crews is less certain, but we do know that over 30 UAS incidents occurred before AF447, and all of them were successfully resolved by their crews.
@AZR - I don't know for certain, but an educated guess says that NCD on a T7 will cause stall warning to cut out, because with no valid data, the stall warning subsystem has nothing to work with.
@Sunfish - This was not a complex or unforeseen failure mode. Unreliable Airspeed Indication causes a drop to Alternate Law, which has no hard protections. This was well-understood by all the engineers, and if it was not communicated to line pilots, it should have been. We know Airbus sent out a bulletin describing a workaround procedure while the problematic pitot tubes were being replaced. How well this was disseminated by airlines amongst their crews is less certain, but we do know that over 30 UAS incidents occurred before AF447, and all of them were successfully resolved by their crews.
@AZR - I don't know for certain, but an educated guess says that NCD on a T7 will cause stall warning to cut out, because with no valid data, the stall warning subsystem has nothing to work with.
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I have read all these AF447 threads. I can only recall one airline pilot who was opposed to connected side sticks. A few thought it would make no difference to the outcome. The vast magority thought connected side sticks would have contributed to a better outcome.
This is just another generalised summary. I dont wish to infame another polarised debate.
This is just another generalised summary. I dont wish to infame another polarised debate.
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@Cool Guys - I think you'll find that the "pro-connection" folks were the same people posting repeatedly. Additionally, I don't think it's a case of pro vs. anti - it's just that objectively there's no evidence that one is superior to the other.
Oozlum bird is going round, going round, going round....
...sang to the tune of "London bridge"
It's even more basic than QRH. They did not understand what was happening so there was no idea what procedure to follow.
No, it would be wrong. Mere incompetence would not kill them. It was their totally inappropriate reaction that wiped them out.
No, but even as you are introspecting, you might be quite wrong. There were more than thirty crews faced with the very similar predicament. All of them survived unscathed. In no case that could be analyzed there was execution of prescribed procedure recorded. Some crews were so overwhelmed they kept trying to reengage the AP while the stable aeroplane flew itself out of the ice, speeds returned and re-engagement was successful.
Surprise, shock, horror, followed by the panicky reaction.
1 and 2 are elements of basic airmanship, 3 is easily dealt with by making the system so good at introduction it needs no major modifications and upgrades. Guess what: there were no major redesigns of FBW in Airbi since they were introduced and FBW Airbi will make a couple of thousands uneventful flights today.
What type? Pilots scared out of their wits pulling into stall?
It was certainly communicated via FCOM and self-respecting companies trained their pilots in altn law flying during sim sessions.
Severe loss of redundancy as each sidestick now has independent position detection. That infamous DLH incident where roll polarity was reversed in left sidestick with interconnected sticks would left aeroplane with no roll control via sticks at all. As it was, alert first officer disconnected capt's sidestick , took overcontrol and everyone lived on happily instead of cartwheeling into forest just off EDDF 18. My gang insisted that during incap practice we push stick fully outboard and forward, simulating falling on it, so everyone gets practice in taking over the priority. Nowadays if I go lights-out during flight and lean my 220 pounds against the yoke, there is no option for my F/O to just remove my controls from control loop. Something to think about, eh?
Opinionated and unsubstantiated. Far from being sufficient to be taken into account by aeronautical powers that be.
I am a pilot and I know that "I am a pilot" uttered on anonymous forum is worthless.
Originally Posted by BOAC
They had a problem. They didn't follow the QRH.
Originally Posted by fantome
would ' which incompetence was the root cause of this horrific disaster' be an improvement?
Originally Posted by Fantom
Am I the first to admit I would have been severely challenged and, probably, overcome by the situation?
Originally Posted by Fantom
What, in your opinion, is the core issue?
Originally Posted by Sunfish
1. Automation must never be totally trusted.
2. It must be possible for the crew to revert to basic mechanical instruments and hand fly the aircraft from first principles.
3. Modifications and upgrades are going to become a nightmare for Airbus because it is impossible to completely understand if new failure modes have been created.
2. It must be possible for the crew to revert to basic mechanical instruments and hand fly the aircraft from first principles.
3. Modifications and upgrades are going to become a nightmare for Airbus because it is impossible to completely understand if new failure modes have been created.
Originally Posted by Sunfish
I expect more of these type of accidents.
Originally Posted by DozyWannabe
This was well-understood by all the engineers, and if it was not communicated to line pilots, it should have been.
Originally Posted by AtomKraft
For Gods sake what harm could be done by linking the sidesticks so they move together?
Originally Posted by CoolGuys
This is just another generalised summary.
Originally Posted by CoolGuys
It's a pity you're not a pilot, Dozy.
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Linked SS
For Gods sake what harm could be done by linking the sidesticks so they move together
With linked SS, PNF should remove his hand to not obstruct the SS movement.
When it is required to take over, he now first have to visually locate the deflected position of the stick,
grab the stick and initially fight the other stick input.
(and not forget to push the button to disconnect the adjacent SS)
Valuable time is lost and forward facing philosophy interrupted in critical phases.
In AF447 linked SS could have contributed to another outcome but in the majority of airborne time it is completely useless and in critical phases it can be distracted or even dangerous (as described above)
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Guys.
If the SS were linked, PNF would have felt (prolly couldn't see) what the PF was doing.
In the panicky atmosphere of those minutes, words lost their impact.
One pilot cocked up, but if the controls were linked it would have needed two pilots to cock up (and stay cocked up) for the accident sequence to continue.
For pitys sake gents- every dual controlled a/c built (apart from Airbusses) has linked controls.
For a bloody good reason.
Rocket science it is not and I think those who argue against it are bonkers.
If the SS were linked, PNF would have felt (prolly couldn't see) what the PF was doing.
In the panicky atmosphere of those minutes, words lost their impact.
One pilot cocked up, but if the controls were linked it would have needed two pilots to cock up (and stay cocked up) for the accident sequence to continue.
For pitys sake gents- every dual controlled a/c built (apart from Airbusses) has linked controls.
For a bloody good reason.
Rocket science it is not and I think those who argue against it are bonkers.
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Originally Posted by A33Zab
With non-linked SS PNF can hold the SS neutral (or rest his hand on SS pedestal), push the red button and direct take over in critical phases when required.
With linked SS, PNF should remove his hand to not obstruct the SS movement.
When it is required to take over, he now first have to visually locate the deflected position of the stick,
grab the stick and initially fight the other stick input.
(and not forget to push the button to disconnect the adjacent SS)
Valuable time is lost and forward facing philosophy interrupted in critical phases.
In AF447 linked SS could have contributed to another outcome but in the majority of airborne time it is completely useless and in critical phases it can be distracted or even dangerous (as described above)
With linked SS, PNF should remove his hand to not obstruct the SS movement.
When it is required to take over, he now first have to visually locate the deflected position of the stick,
grab the stick and initially fight the other stick input.
(and not forget to push the button to disconnect the adjacent SS)
Valuable time is lost and forward facing philosophy interrupted in critical phases.
In AF447 linked SS could have contributed to another outcome but in the majority of airborne time it is completely useless and in critical phases it can be distracted or even dangerous (as described above)
Unlinked SS: PF comes in for landing , does the flare pitch wise ok but wings are not level. Me, as PM have to take over by pressing the TO Button. Unfortunately I have no idea now, how much elevator he pulled. So, I have to guess...
The unlinked Sidesticks (and the non moving thrust levers, too) are just downright ridiculous. And so is the QRH, the FCOMs, and and and
