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-   -   AF447 wreckage found (https://www.pprune.org/tech-log/447730-af447-wreckage-found.html)

bearfoil 9th June 2011 01:27

"From the AF447 report: From 2h 10min 05sec, the autopilot then auto-thrust disengaged and the PF said, "I have the controls". The airplane began to roll to the right and the PF made a left nose up input. The stall warning sounded twice in a row. At 2h 10min 16sec, the PNF said, "So, we've lost the speeds" then "alternate law". The airplane's pitch attitude increased progressively beyond 10 degrees and the plane started to climb." "

Show me where, exactly, this concludes (or even says) that the Climb was initiated by the pilot. Careful.

WilyB 9th June 2011 01:59


The whole idea of the sim is it will do exactly what the plane would in the real world....
Daddy,

I am sure you are correct, and with my 0 vs. your 26K hours of flight SIM who am I to argue, but the Airbus and Boeing actual test pilots appear to have a very different point of view.


USE OF SIMULATORS

We manufacturers were very concerned over the types of manoeuvres being flown in simulators and the conclusions that were being drawn from them. Simulators, like any computer system, are only as good as the data that goes into them. That means the data package that is given to the simulator manufacturer. And we test pilors do not deliberately lose control of our aircraft just to get data for the simulator. And even when that happens, one isolated incident does not provide much information because of the very complicated equations that govern dynamic manoeuvres involving non
linear aerodynamic and inertia effects.

The complete data package includes a part that is drawn from actual flight tests, a part that uses wind tunnel data, and the rest which is pure extrapolation. If should be obvious that conclusions about aircraft behaviour can only be drawn from the parts of the flight envelope that are based on hard data. This in fact means being nol far from the centre of the flight envelope; the pari that is used in normal service. It does not cover the edges of the envelope. I should also add that most of the data actually collected in flight is from quasi-static manoeuvres. Thus, dynamic manoeuvring is not very well represented.
http://www.ntsb.gov/Events/2001/AA58...its/240005.pdf

Poit 9th June 2011 02:13

I've had an opportunity to discuss this with a friend of mine who flys military A330s. He hasn't had a chance to read the report, but when I queried him on the pilot's maintenance of a nose-up attitude, his only explanation was that they believed they were in an over-speed situation, rather than a stall.

Incidently, I flew from London to Sydney on A340s several days ago, and I couldn't help but imagine the aircraft falling from our cruise in little over 3 minutes! It was the first time I've EVER felt uncomfortable on an aircraft. This should never have happened, and the boffins who design these modern marvels need to make sure the pilots retain the authority and ability to recover an aircraft in distress.

Someone else mentioned that a 747 would 'roll over and do what you want it to' in such a situation. I can't comment on the differences between the two manufacturers, but it would appear to me from various comments I've read that Airbus needs to incorporate some slightly more pilot-intuitive aspects to the way the aircraft relates to its crew.

As a pilot who trained in the military, I'm still shocked and dismayed by the chain of events that unfolded.

bubbers44 9th June 2011 02:30

Poit, the Airbus people will say you are trying to send technology back 25 years so you must adjust to total automation. Pilots now manage autopilots and the computer because it can do it better most of the time. Handflying skills are no longer required.

WilyB 9th June 2011 02:33

Poit


It was the first time I've EVER felt uncomfortable on an aircraft. This should never have happened,
I agree: what's wrong with you? ;)

Poit 9th June 2011 03:20

Bubbers44: Clearly hand-flying skills ARE still required, as this accident tragically illustrates. Hence my point. Sure, computers can do a better job, but when they decide to pack it in (as happened in this case) the pilots need to have a pilot friendly and intuitive aircraft to fly. A combination, therefore, between the highly advanced, and old-school simplicity.

WilyB: LOL. This accident (and several others...such as the QANTAS A380) has made me question that pilots are system operators, and no longer aviators. Thankfully the QANTAS event ended without any casualties, but it could have quite easily gone in another and far more horrific direction.

These things never happened in the old, classic 747's. Maybe it wasn't so bad 25 years ago Bubbers!

iceman50 9th June 2011 03:35

Bubbers44

We know you despise Airbus and do not understand it, so please no more useless posts.


Captdaddy

Do not know what kind of simulator you were flying but when I taught unusual attitudes the instruments never went to big red crosses. Ever heard of controlled precession, because you can see it in the simulators I have "flown".

BASIL's CUT and PASTE

The post that was copied and pasted from the "one of the most experienced A330 pilots in the world". A lot of what he has said is absolute rubbish and you would not think it came from such an "experienced A330 pliot", e.g. you would not want to follow the FD's if you were in AF447 position as it would be giving erroneous information. Altitude is the least of your concerns at that point in time, ATTITUDE and POWER are the life savers. If you have stalled, you MUST unstall the wing and add power progressively to be able to counteract any pitch up due to the low slung engines. As for the thrust going to climb power it freezes at the setting just prior to disconnect, with the Thrust Lock function. The non-moving thrust levers are NOT an issue. If you disconnect the A/THR you match the blue 'donuts" then disconnect, in the AF case the thrust levers could have been left in the detent and moved to the correct power setting when required. Even if it went to climb thrust there would not be a huge increase in thrust and you certainly would not stall. As for never being trained in stalling, you never train to stall in the simulator, but most regulators require approach to the stall recovery training as part of the Type rating requirements. But there again what would I know only been flying the Airbus A330/A340 since 1996 and for those that wonder flew 757/767 for 6 years before that, so seen both manufactures!

Poit 9th June 2011 05:00

Iceman, given your experience with both major manufacturers, do you have a theory as to what went wrong on this occasion? I'm not being sarcastic in asking that, just want the benefit of someone who's got experience with these aircraft.

Is there a difference between Airbus and Boeing (you might not want to answer that)?

ChrisVJ 9th June 2011 05:27

I asked a question earlier but it was one of several and did not get answered with the others.

The glass indicates when the ASI is unreliable and the autopilot disengages as its inputs don't agree.

Is there anything that sounds etc to say that the ASI has become reliable again? Would it be possible for pilots, perceiving the ASIs to be intitially wrong to continue to do so to the exclusion of paying attention to attitude?

Just how tight is coffin corner at FL 380?

NigelOnDraft 9th June 2011 05:29


These things never happened in the old, classic 747's
No, they never did:
Air India 747

KAL 747

Air China 747


As for the thrust going to climb power it freezes at the setting just prior to disconnect, with the Thrust Lock function
There are failure modes, including inadvertant disconneciton, where they do run to full (CLB) power.


...and the boffins who design these modern marvels need to make sure the pilots retain the authority and ability to recover an aircraft in distress.
How can you conclude the "boffins" have not made sure of this in the AF A330 crash? In the TC incident, they had the ability (but "chose" not to use it) to control the aircraft. As the above links show, the "boffins" add these protections in an attempt to increase safety. Some of the above accidents could not occur in the same manner in a FBW Airbus...

I am not overly for or against the Airbus v Boeing philosphy - I have flown both. But until we get a full analysis from the BEA, it is hard to see whether the FBW "laws" were a (significant) factor.

Graybeard 9th June 2011 05:31

Old Airplane with Control Problem
 
About ten years ago, the Roll Channel went to sleep on an Evergreen 747-1 cargo plane one night over Canada enroute KJFK-KANC. It was well beyond 30 degrees roll when the pilot caught it. They went something like 1.06 M in the recovery.

SperryWell could find nothing wrong with the roll channel, so it became a boat anchor. EV installed 30 degree bank limit alarms in the fleet after that.

RWA 9th June 2011 05:54

Iceman 50


Altitude is the least of your concerns at that point in time, ATTITUDE and POWER are the life savers. If you have stalled, you MUST unstall the wing and add power progressively to be able to counteract any pitch up due to the low slung engines.
Agree, Iceman50. I wonder, though, whether that procedure (attitude first, then power) was 'in force' at the time of AF447? I ask because I recall reading this a while back - a 'new' approach (well, actually, the 'old' one) published by Airbus in 2010, long after the AF447 accident? According to the poster, and many of those who replied to him, previous advice was along the lines of 'full power and seek to maintain assigned altitude'?

http://www.pprune.org/tech-log/41537...procedure.html



As for never being trained in stalling, you never train to stall in the simulator, but most regulators require approach to the stall recovery training as part of the Type rating requirements.
Thanks for that information. Obviously you couldn't have pilots in training practise actual stalls in a real transport category aircraft, but up to now I'd been assuming that some sort of 'simulated stall' could be practised in the simulator.

So, on the face of it, pilots can only be taught 'stall avoidance,' and there's no way to train them in actual 'stall recovery' - except, of course, that they'll have practised it in light aircraft in their early flying lessons?

Roseland 9th June 2011 06:41

Stall recovery procedure
 
Shouldn't it include checking you aren't trimmed fully nose up?

Man Flex 9th June 2011 07:48

studi,

With respect, read the report.

The protections were not available because the aeroplane had reverted to Alternate Law 2. That means that the pilot is fully responsible for the aeroplane's course except load factor limitations which are still applied.

The A/P and A/TH failed at the moment that the probes froze over and the airspeed readings became unreliable.

The F/O took control.

The F/O made persistent nose-up inputs - not the autopilot.

I reiterate that now the mystery is why he made those inputs.

Any alternative discussion on this thread or any other is quite frankly, irrelevant.

aterpster 9th June 2011 07:55

For all you current Air Bus pilots. Is this guy telling it correctly?

AVmail: June 6, 2011

Good memories 9th June 2011 08:06

Not according Iceman50. But like you Aterpster, I am very interested in the opinion of experienced and objective Airbus pilots.

iceman50 9th June 2011 08:24

Poit

I have my own theory but it will stay that until the report is out, no point in posting it here as it would be speculation.

There are differences between Boeing and Airbus philosophy and on both there are some good things and some not so good things. The whole point is you have to "learn" the aircraft you are flying and not continually think back to previous types, didn't do that on a ......... (insert A/C type here). That's what we as "pilots" are supposed to do. Any A/C with the AP / A/THR (Autothrottle) off are still aircraft and subject to the same rules of flight as your small cessna or chipmunk.

RWA

It was not just Airbus that re-stated the "new / old" stall procedure, Boeing did as well. I believe that Boeing, Airbus, other manufacturers and the regulators got together and the "new/old" procedures were emphasised. This was after events like Turkish in AMS (with moving throttles) and Colgan at Buffalo. The same thing happened when the revised procedures for Smoke and Fumes were changed a couple years ago. Manufactures and regulators assessing the most likely causes of Smoke and Fumes and devising a checklist priority, with reminders that an off field landing may be required should the fire escalate.

aterpster

Good memories beat me to it!

jcjeant 9th June 2011 09:09

Hi,


I have my own theory but it will stay that until the report is out, no point in posting it here as it would be speculation.
"Sarcastic mode open"
What a great contribution from a A330/A340 expert
"Sarcastic mode closed"
But of course it's your right to have an opinion and not post it !
I wonder why you post here in the first place ? (Rumours and news)
BTW Bubbers44 have also the right to have an opinion (despise Airbus) .. and he post it.
Why fallen in love with a girl you don't like ?

iceman50 9th June 2011 10:20

jcjeant

I have not posted my opinion as I / we do not have all the facts.

I posted as I am fed up with the total nonsense that is sometimes spouted and do not want to add to the "speculation / Airbus bashing frenzy".

Just in case you are still unsure, I get great pleasure flying the A330 / A340 and do not wish to return to Mr Boeing. A blue cockpit is so much nicer than brown!;)

Yes, Bubbers has a right to an opinion but the endless Airbus sniping is boring and does not bring anything to the debate.

Basil 9th June 2011 10:42

iceman50,
Your comment, for which thanks, is the reason why I posted that reference.
With a personal Airbus total of half an hour in the A320 sim I'd no idea whether the writer was talking sense or not.
I think that this is a great thread and, when I next pax in a 'Bus, I hope that the drivers have read it.


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