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AF447 final crew conversation - Thread No. 1

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AF447 final crew conversation - Thread No. 1

Old 15th Oct 2011, 16:56
  #81 (permalink)  
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OK, Dozy - I give in..........let's see how many AF447 threads we can generate.

FLEX - VSI is normally 'instantaneous' inertial then tapered by barometric.
the VSI would have been a good confirmation that the aircraft was going downhill?
- you mean apart from the rapidly unwinding altimeter? (and thought possibly to be 'off scale' and not visible?)
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Old 15th Oct 2011, 17:14
  #82 (permalink)  
 
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It's a very different type of aeroplane, but I used to demonstrate this type of stall to Air Cadets learning to fly the Venture motor-glider. The stall scenario to be taught was the classic reducing IAS, buffet, and nose-drop. But I liked to demo also a more subtle stall where you end up with a reasonably normal attitude and power, but with the stick hard back, very low airspeed, and the VSI off the clock.

The only indications that you were stalled were the control column position, IAS, and the vertical speed. It was even a very smooth ride!

Simply releasing the back-pressure effected immediate recovery.

I suspect that simply releasing the back-pressure in this case might have been sufficient to recover very rapidly.

Having flown an aircraft type, of which two were lost to deep-stalls (HS 121), and several other types where the HS is not blanked by the stalled wing, I think the former were your worst nightmare. The latter could almost be likened, aerodynamically (and for the pilot-held-stall-condition) to those old RAF motor-gliders.

I realise that is a gross simplification, but few pilots (I suspect) were ever demonstrated the pilot-maintained stall.

Last edited by Aileron Drag; 15th Oct 2011 at 18:10.
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Old 15th Oct 2011, 18:17
  #83 (permalink)  
 
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Hope you have a tin hat DA !

This thread is like an echo from the edge of the universe, back to deep stall and THS authority. There was a mountain of stuff on this in Tech Log Thread #4 including (916),

"If THS > 8 up (and no autotrim available), full elevator pitch down authority may be insufficient for speeds above 180 knots."

...at reasonable attitude of course. However is the distinction between stall, deep stall relevant as no apparent sustained attemp at ND is evident, less that it was wanted but the THS frustrated it. Back to Tech Log !
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Old 15th Oct 2011, 18:21
  #84 (permalink)  
 
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Quote:
Originally Posted by DW
I can't help but think this conversation is off topic (which is the book and accompanying Daily Heil article), and properly belongs in the Tech Log thread however.

- good call, Sir.
To the contrary, pedantic rants discussing the nuances of pitch characteristics in various AB FBW laws belong in the tech section. (not accusing you of rants btw)

This string is about the final statements uttered by the doomed crew and I suspect that many readers can't understand why something as simple as a stall killed 200 someodd persons. And why the crew would be so totally confused. That in itself is quite a different subject than the latest AF447 string. Contrary to the name, it's quite obvious that professional pilots make up something less than the majority around here. I think it reasonable to keep this string alive and out of the purgatory called AF447 string 1,2,3,4,5,6, and so on.
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Old 15th Oct 2011, 18:47
  #85 (permalink)  
 
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Aileron Drag:
It's a very different type of aeroplane, but I used to demonstrate this type of stall to Air Cadets learning to fly the Venture motor-glider. The stall scenario to be taught was the classic reducing IAS, buffet, and nose-drop. But I liked to demo also a more subtle stall where you end up with a reasonably normal attitude and power, but with the stick hard back, very low airspeed, and the VSI off the clock.

The only indications that you were stalled were the control column position, IAS, and the vertical speed. It was even a very smooth ride!

Simply releasing the back-pressure effected immediate recovery.

I suspect that simply releasing the back-pressure in this case might have been sufficient to recover very rapidly.

Having flown an aircraft type, of which two were lost to deep-stalls (HS 121), and several other types where the HS is not blanked by the stalled wing, I think the former were your worst nightmare. The latter could almost be likened, aerodynamically (and for the pilot-held-stall-condition) to those old RAF motor-gliders.

I realise that is a gross simplification, but few pilots (I suspect) were ever demonstrated the pilot-maintained stall.
In the Airbus 320 series (I don't fly the 330 but believe it to be the same), releasing the side stick would have simply resulted in the computers attempting to maintain one g-force. The AB trims for g-force, not for speed. Your technique works in aircraft that trim for speed. The Airbus is somewhat different, to say the least.

Anything more belongs in the tech section.
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Old 15th Oct 2011, 19:20
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TTex600,

The principle is, perhaps, the same. It doesn't matter what the autoflight system is aiming at if the back-force is released - a trimmed speed or a certain 'g'.

Fact is, these guys were positively demanding maximum pitch up. Or, to put it another way, max positive 'g'.

Sorry, my knowledge of the Airbus range is nil - I was a Boeing dude. All I can see here is this crew failed to realise that a very high pitch attitude, full power, stick hard back, zero speed, and VSI off the clock was indicative of a pilot-maintained stall.

I know it's easy to pontificate from my retirement armchair, but I had noticed in my final years of professional flying (B777) that the 'new generation' of F/Os had poor basic flying skills - having been brought up in a fly-by-wire world, and in an ab initio system which had banned spinning training because it was 'dangerous' !

The Tech thread, by the way, has become a little ethereal for some of us!
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Old 15th Oct 2011, 19:34
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I think most pilots understand what was happening here, and only in hindsight, of course. To those who have not been confused whilst flying an aircraft, hats off. Ordinarily, sit on hands is wise advice.

These guys were forced to sit on their hands and try to think themselves out of a crash. That's hard, and deserves more respect than some are showing.

They had tried "everything" (according to them), and nothing had worked.

What sort of mindset would paint them so far into the corner?

Loud airstream: High velocity. Common sense.

Astonishing Descent: Fear factor.

Fairly stable g loading: "Stable Flight", suggesting "In control"

Pitch "Stable", but "NOSE DOWN": "Obvious", the controls were chronically commanding NOSE UP, and no sense of climb, or rotation is felt.

They had agreed already they were out of options, they told the Captain that, on his entry into the flight deck.

So it seems simple, and not difficult to get. They didn't get STALL data such that they followed it in, and not knowing they were STALLED, they did not think to control out of it.

It isn't so obvious that they were "stupid", and it is outrageous that anyone would continue to dismiss their efforts at recovering the a/c.

This deal to me is mostly HF, and some non-serendipitous events that conspired to trap the crew into their destiny.

There is also no firm foundation for faulting "training". It is difficult to justify the lack of attention paid to UAS likelihood on long flights. To me, there is not one person here who has the chops to criticize the "lack of Manual Flight skills" exhibited once the a/p was lost to faulty speeds.

It is arrogant to be dismissive of the pilots' efforts.
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Old 15th Oct 2011, 19:43
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Get real, Lyman. They kept the stick hard back. There was little or no attempt at recovery. They did not know they were stalled.
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Old 15th Oct 2011, 20:43
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My two pennorth worth-. The Airbus Efis layout on their FBW aircraft can be cluttered in comparison to a traditional aircraft.All the info is there on one screen and it is up to the weak link(the pilot ) to unpick it. I do not believe a tape altimeter stands out as well as a needle and a drum altimeter as they unwind rapidly. Imagine a needle unwinding rapidly and how easy that is to interpret. The VSI also on the EFIs is very small .i noticed that my scan when I flew 320/330 was very poor as you basically were looking at one screen . Contrast that with having to scan individual instruments and process what they were telling you. You probably spend a few microseconds longer doing this but that extra time can trigger something that tells you something is wrong. With an older aircraft I have a healthy disrespect about what it is telling me and i qualify this by looking at pitch power and performance. When I convert to a new type I always look at the unreliable airspeed checklist to learn the pitch and power combinations that work. i do my best to fly by these and no matter the complexity or sophistication of the aircraft they can all turn back into a basic aircraft with in this case was a very simple failure.(blocked pitots).
I have had the same failure in a non fbw airbus but it was flyable as we hand fly it a lot,we don't trust it ,and we flew pitch and power. The 330 shouts stall at you in a loud masculine voice and whenever i heard it in The sim my arm always wanted to push the nose down so why didn't this trigger a similar response?
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Old 15th Oct 2011, 21:13
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This may be a watershed for cockpit design

The pilots flew a perfectly good plane, straight into the salty sea.

It seems that the FBW automation has led to an ergonomic failure, normally certified pilots are simply not capable anymore of figuring out what the instruments are telling them and flying this plane in the presence of fairly minor mechanical faults like pitot blockage.

I suspect that we will see a major redesign of future automation control interfaces and cockpit instrumentation as Airbus digests the data of this accident. We will probably also see some major changes in pilot training, maybe even a greater emphasis on seeing pilots handfly the plane to keep their hand in.

I suspect that the smarter souls at Airbus and the certification authorities already suspected most of this, and their suspicions informed the huge search operation which provided the proof to push home aircraft design and pilot training changes.
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Old 15th Oct 2011, 21:55
  #91 (permalink)  
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We will all learn from this accident, at least I hope we will. Well I have, anyway.

BIG RoD, Smooth flight:

Levers back, nose down.

And........................

Recover.



Surely a message from the (AF447) Grave, for all who'd care to hear it.
 
Old 15th Oct 2011, 22:22
  #92 (permalink)  
 
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Holding yoke or side stick all the way back for 3.5 minutes is not in any flight manual on how to fly an airplane even if you don't know why the airplane is out of control. These guys were poorly trained and were not qualified to be flying that airplane. The only qualified pilot was taking his rest break so when he got up there he had little time to figure out how they had gotten into their situation. How can airlines keep hiring pilots of this low capability to fly these wide body aircraft when they know the junior guys will be flying together with little experience?

We know it is illegal to make the captain stay in the cockpit at all times if the flight is over 8 hrs. Make them put two qualified captains on long range flights so at least one pilot knows how to fly if the automation fails. That is how we did it on my first airline job. My last one was like AF but the FO's were qualified high time pilots. Not like these noobys.
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Old 15th Oct 2011, 22:34
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Originally Posted by bubbers44 View Post
These guys were poorly trained and were not qualified to be flying that airplane. The only qualified pilot was taking his rest break so when he got up there he had little time to figure out how they had gotten into their situation.
That's a little harsh. Look at the transcripts and you'll see that the senior (albeit not by much) F/O - acting as PNF - seems painfully uncomfortable with how the aircraft is being handled, but it is only when the Captain arrives in the flight deck that he feels he has the authority to act (notably *emphatically* preventing the PF from deploying the speedbrakes). Up until that point he tries to correct the PF verbally, but does not take control of the aircraft.

The way I read it, it looks like he knew something was wrong, but because the Captain had implicitly put the junior F/O in charge, he felt he was unable to act beyond a certain point.

The situation that bothers me is that the Captain did not explicitly determine responsibilities before heading for his rest break. On top of that he elected to put the junior F/O, who was returning from vacation, in charge during the relief phase of the crew roster. This is illogical to me, especially given that he knew that they were about to transit the ITCZ during a time of year when it is known to be challenging to fly through. I don't know how it is for pilots, but when I'm back at work from vacation, it takes me a day or two until I'm properly "back in the groove".
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Old 15th Oct 2011, 23:29
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Again? whatever.
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Old 15th Oct 2011, 23:32
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DW, so you think the way the FO's handled the situation was correct and a fully qualified captain in the cockpit is not necessary? What fully qualified captain would hold the controls all the way back for 3 and a half minutes? Non that I know of. If the captain had been in the cockpit when they lost airspeed he would have handled it like all of us would have. Flown attitude and power setting until clear of the weather, not pulled up and stalled. I guess every country is different but that is what we do.
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Old 15th Oct 2011, 23:37
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I think Bubbers' post was correct.

In addition:

Can't fly: Not a pilot.
 
Old 16th Oct 2011, 00:03
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That's a little harsh. Look at the transcripts and you'll see that the senior (albeit not by much) F/O - acting as PNF - seems painfully uncomfortable with how the aircraft is being handled, but it is only when the Captain arrives in the flight deck that he feels he has the authority to act (notably *emphatically* preventing the PF from deploying the speedbrakes). Up until that point he tries to correct the PF verbally, but does not take control of the aircraft.
Dozy, it isn't exactly a democracy in the cockpit. It is more of a meritocracy. You warn the other person that they are f'ing up if time permits and then act if you hope to be bouncing your grandkids on your knee.

Problem is that PNF did not act, he punted the problem to the Captain. That is as much of a problem as is PF's handling of the aircraft.

The reasons the PNF did not act need to be understood and corrected.
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Old 16th Oct 2011, 00:03
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ttex600: In the Airbus I fly, the only concrete information I can see from my seat is the horizon in front of the windscreens. EVERYTHING else is computer/electronically generated. Please remember that when you question the actions of three pilots who were faced with: dark skies, thunderstorms, unreliable instruments, turbulence, no visible external cues, myriad ongoing nuisance warnings, .............. This was NOT an accident caused by a single factor!(IMHO) The final finding will likely indict everything from aircraft systems and philosophy to government oversight to airline training philosophy. In the mean time, let's not waste the opportunity to change things for the better by taking the easy way out and blaming the dead guys.
Getting back to the fact that pitot tube failure/blockage was the initial cause, I have temporarily lost both ASI's during atmospheric research until clear of clouds in a DC-8 due to the amount of water encountered inflight. The result? I'm still here. The airplane didn't fall out of the sky. The only 'law' we had was pitch/power (with moveable power levers, BTW)...and the autopilot will not trip off (if on) due to lack of airspeed. No auto-throttle and the FD is usually off. Amazing stuff, eh? Given AF447's experience, I wouldn't want to do the same research in a Scarebus.

As 411 used to say: "Them's the facts."
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Old 16th Oct 2011, 00:12
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Originally Posted by bubbers44 View Post
DW, so you think the way the FO's handled the situation was correct and a fully qualified captain in the cockpit is not necessary?
That's not what I said at all! I said that the senior F/O seemed to have more of a clue what was going on, but only intervened verbally until the Captain arrived. I also said that the way the Captain performed the handover was an example of poor CRM, because he did not explicitly brief the F/Os on who would be acting as relief pilot, nor did he provide the senior F/O with any boundaries at which he could take control (which, according to Interim 3, should have been standard AF procedure).

What is necessary in the flight deck is at least one competent pilot, preferably two. Rank can sometimes be immaterial - remember Palm 90, where the F/O was clearly the more qualified and switched-on pilot of the two, but did not feel he could override his Captain.

What fully qualified captain would hold the controls all the way back for 3 and a half minutes?
The Captain of Birgenair 301 and the Captain of ColganAir 3407 for starters.
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Old 16th Oct 2011, 00:56
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Qualified Pilots?

Quote:
What fully qualified captain would hold the controls all the way back for 3 and a half minutes?
The Captain of Birgenair 301 and the Captain of ColganAir 3407 for starters.
If I may beg to differ.... The captain of CG3407 had failed several checks.

The only qualifications whatsoever that I hold for commenting is that I have read all of the posts in all of the AF447 threads!
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