Reply to: Air France Crash - shocking

[OwlHoot]

The CUK armchair experts strike again with misinformed speculation and complete bollux all round.

It's amazing what you can do in an armchair - Guide a plane safely through a storm, run a military campaign better than the general staff, coach a national football team to victory, and all with only with a brace of tinnies.

AtW will be able to fix the economy single handed once his sofa arrives.

[scooterscot]

I just had a thought...

The A/C was flying into a storm? or was in it?

I wonder if SEU's could have play a part.

High (and low) energetic particles from space, increasing with altitude, alter the logic of a memory device. Failure is not always the outcome. It is something I've spent a lot of time studying.

[doodab]

agree with earlier poster there should be some sort of independent instruments obviously air speed is difficult but ground speed would give you a good minimum?

The "air speed" on the gauge isn't actually the speed through the air, it's basically a measure of how much air is going over the wings in terms of equivalent speed at sea level i.e. it corrects for pressure changes with altitude. So basically you know that whatever altitude you are at, go below X on the airspeed dial and you are going to be in a bit of trouble.

[vetran]

agree with earlier poster there should be some sort of independent instruments obviously air speed is difficult but ground speed would give you a good minimum?

[scooterscot]

Glass cockpits

I do wonder how much instrumentation failure had a part to play in this, I guess time will tell.

Perhaps a possible dormant failure that not activated until the stall occurred is responsible?

This is when we discover the failure mode analysis was completed by somebody who previously worked in the post office.

[sasguru]

The CUK armchair experts strike again with misinformed speculation and complete bollux all round.

[SueEllen]

Very confusing. Avoid getting on an Airbus A/C should I?

Probably because of this - BBC News - Airbus faces manslaughter charges over Rio crash

Interestingly can't find out what happened to the charges.

This is interesting listening - http://www.bbc.co.uk/programmes/b010025s (It's not about Air France.)

[Cliphead]

There's better quality speculation here.



They were probably already deeply stalled at this point (perhaps having been taken to the cusp of the stall by the autopilot before it handed control to the pilots). The irony is that the autopilot was the only one to survive.

Highlighting mine
[ PF= Pilot flying ]

Glass cockpits

I do wonder how much instrumentation failure had a part to play in this, I guess time will tell.

[TimberWolf]

Is it... At 3,000 feet it might be. But at FL300+, surely the only obvious thing to do is push the nose down and build up some speed to stablise the aircraft

It's such a basic thing that you have to think that their instruments were telling them something else was happening.

There's better quality speculation here.

At 2 h 12 min 02, the PF said "I don’t have any more indications", and the PNF said "we have
no valid indications". At that moment, the thrust levers were in the IDLE detent and the
engines’ N1’s were at 55%. Around fifteen seconds later, the PF made pitch-down inputs. In
the following moments, the angle of attack decreased, the speeds became valid again and the
stall warning sounded again.

They were probably already deeply stalled at this point (perhaps having been taken to the cusp of the stall by the autopilot before it handed control to the pilots). The irony is that the autopilot was the only one to survive.

Highlighting mine
[ PF= Pilot flying ]

[centurian]

The pilots reacted to the stall warnings with maximum thrust -- just as was called for in the training manuals. But they also pulled the nose of the aircraft up. It is an intuitive thing to do, but aeronautically it is a serious error.

Is it... At 3,000 feet it might be. But at FL300+, surely the only obvious thing to do is push the nose down and build up some speed to stablise the aircraft

It's such a basic thing that you have to think that their instruments were telling them something else was happening.

[scooterscot]

Starting to sound like pilot error:

The pilots reacted to the stall warnings with maximum thrust -- just as was called for in the training manuals. But they also pulled the nose of the aircraft up. It is an intuitive thing to do, but aeronautically it is a serious error.

Doomed Flight AF 447: Questions Raised about Airbus Automated Control System - SPIEGEL ONLINE - News - International

But then is goes onto say:

"No matter how hard the crew tried to push down the nose of the aircraft, they would have had no chance," Hüttig says. He is demanding that the entire fleet of Airbus A330s be grounded until the phenomenon is adequately explained.

Very confusing. Avoid getting on an Airbus A/C should I?

[Cliphead]

Maybe one of the flyers here can answer this. If you're descending rapidly or in a stall, and given plenty of height, can't you just put one main flap up and the other down, with tail flaps both down, to turn or "fall away to the side", then hopefully sort of turn that into a dive. Then, once you pick up speed, you could hopefully level off back into normal flight.

Flaps aren't controllable individually but extend on both wings at the same time and would be useless anyway in a stall. No idea what stall recovery technique a pilot would use on an airliner but with any aircarft the number one priority is to gain airspeed .

In my case level the wings, stick forward to get the nose down, throttle to the firewall and pull up before hitting the ground. Been practising stalls recently as different types of aircraft can show different stall characteristics and it's important to recognise the onset. Strangely they dropped spinning recovery from the syllabus some time ago.

[TimberWolf]

Maybe one of the flyers here can answer this. If you're descending rapidly or in a stall, and given plenty of height, can't you just put one main flap up and the other down, with tail flaps both down, to turn or "fall away to the side", then hopefully sort of turn that into a dive. Then, once you pick up speed, you could hopefully level off back into normal flight.

I saw that method mentioned in at least one post, though other speculation counters that the automatic systems still operating might have resisted it. Someone also mentioned moving everyone toward the nose of the aircraft. But I'm not convinced the pilots knew that they had stalled.

[OwlHoot]

Maybe one of the flyers here can answer this. If you're descending rapidly or in a stall, and given plenty of height, can't you just put one main flap up and the other down, with tail flaps both down, to turn or "fall away to the side", then hopefully sort of turn that into a dive. Then, once you pick up speed, you could hopefully level off back into normal flight.

[TimberWolf]

Lots of interesting speculation here, including that the autopilot took them into deep tulip and dumped them up there without a paddle, plus the warning systems that were remaining gave misleading indications. For example because the aircraft was so deeply stalled and out of a valid operating range (airspeed too slow) that the stall warning turned itself off, and turned back on when the pilots pushed down the nose partly restoring the situation, because the sensors started receiving credible data, then turned off again as the pilot hastily pushed the nose back up. In that scenario they thought they were plunging to the ground nose first rather than tail first. All speculation, but reading through the posts, some from experienced airline pilots, goes to show how complex flying a plane that does everything for you can become when things go wrong.