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AF 447 Thread No. 5

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AF 447 Thread No. 5

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Old 13th Aug 2011, 00:35
  #1981 (permalink)  
 
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jcjeant - actually pilots should be encouraged to fly. The computer should monitor flight parameters and if the PF does something stupid the computer takes it back for five minutes before the PF can reacquire control. Too many of those incidents and he is flunked for his "training exercises."

These days there is enough computing power to make this feasible as a way to keep the pilots on the ball, well experienced, and well trained.
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Old 13th Aug 2011, 00:38
  #1982 (permalink)  
 
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I will wait the final report, and more detailed CVR, before taking a final view on whether this crew could have recovered the situation once the death plunge began at FLT380. Intimacy with hand flying their aircraft was missing.
Of course it was recoverable...

And let's call it a final descent, or similar, not a 'death plunge' - no one was consciously diving off a hotel roof !

Last edited by HarryMann; 13th Aug 2011 at 00:41. Reason: correcting sense of a sentence
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Old 13th Aug 2011, 00:41
  #1983 (permalink)  
 
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ChristianJ - let's not feed the troll. Simply ignore him using the control panel.
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Old 13th Aug 2011, 00:47
  #1984 (permalink)  
 
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HarryMann

The key issue was to avoid the stall, after the A/P and A/T disconnection.

But there was still plenty of height to play with in which to recover from this aerodynamic stall, if properly diagnosed and addressed. You can't rely on one pilot up front always having come into civil aviation from a military fast jet background.

JD-EE

Yes, regulations should require some manual flying within the AB flight envelope - as opposed to line pilots having to explain to flight ops why manual flight has taken place. Emergencies such as this are not the time to try out any neglected basic airmanship skills.
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Old 13th Aug 2011, 00:54
  #1985 (permalink)  
 
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HarryMann

(1) The key words were "this crew", in the context of the CRM issues that have arisen. It is much easier to avoid an aerodynamic stall, than to recover from a FLT100 per minute plunge.

(2) "Death plunge" - provocative language, but to remind some posters what an (uncorrected) aerodynamic stall involves. There is only ever one ending.

The stall alarm repeatedly sounded, when within parameters.

Last edited by Welsh Wingman; 13th Aug 2011 at 01:08.
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Old 13th Aug 2011, 01:10
  #1986 (permalink)  
 
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JD-EE

One limitation of automated cars at present is that they may see and avoid a ball coming from in front of a parked car - but not anticipate that the ball may be followed by a child, as yet unseen.

Traffic on the taxyways gets held up by dense fog, as happened at Heathrow a year or two ago. Decca Navigator was almost accurate enough to use as a landing approach aid at Manston. We used to ink the charts. (The runway was very wide and we used the centre part anyway. FIDO had been removed.)

Reverse taxying would need practice. Do remember to take your feet off the brakes when going backwards. You MUST use forward thrust to stop going backwards or...!
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Old 13th Aug 2011, 01:35
  #1987 (permalink)  
 
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A theoretical.

The Pilot accomplished the climb with the a/c following his commands.

WW, Harry Mann

Had the Pilot recovered the STALL, found himself in a high velocity descent, would the a/c have responded with similar control movements, and 'g'? Could he have commanded sufficient Nose Up to exit the dive successfully? Does the a/c limit the g available at the stick to prevent a recovery before hitting the Ocean? What are the limits to a successful recovery (pullout), imposed by the a/c's control system?

Again, a hypothetical.

Thanks
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Old 13th Aug 2011, 02:04
  #1988 (permalink)  
 
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@Lyman

If you are indeed another alias for bearfoil - which is in itself a breach of the rules on most forums, then you'll know full well that the question you've just asked was answered - several times - on previous threads. If you're having a good cackle forcing people to repeat themselves over and over, it's not big and it's not clever.

For the benefit of new posters/followers of this thread I'll repeat once and once only - The aircraft was in Alternate Law 2 (aka NO PROT) - in this control law there are *no* hard limits on the attitude that the aircraft can be put into. There are soft limits, but the pilot can override them simply by manipulating the flight controls (as demonstrated by the THS response). The pilot has *full authority*.
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Old 13th Aug 2011, 02:33
  #1989 (permalink)  
 
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I have not read the answer before, that is fact, and you have not answered it still.

The Pilot did not have "Full Authority" in the climb, his stick wanted it, but the a/c responded with less than the absurd amount he was commanding. Until the loss of energy, when the a/c allowed/deflected the controls to the limit, and kept them (THS) parked at max through the STALL, and down the other side. The climb was allowed by the a/c in "bumps" of elevator only, the THS stayed rigid at -3 degrees. That is NOT full authority, and good on it.

My question involves the descent. Why did the THS stay hard against the curb, independent of elevator command, and why was the elevator deflection ineffective in curing the STALL? Did it have to do with 'g'? airspeed? What, then. The last part of my question I repeat. If the pilot had gotten her flying, Would the pullout be hindered by the same limits I see in evidence in the CLIMB?

This is getting old. As you know, we have communicated PM, as I have with the others who prefer getting upset to being forthcoming.

There are enough high horses here to have saved Napoleon. One or two might consider dismounting.

What is abjectly lacking here most of the time, is deference to the dead; Instead we get childish fan clubbing, and wounded egos.

Website PROTOCOL? Are you serious?
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Old 13th Aug 2011, 08:52
  #1990 (permalink)  
 
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The stall alarm repeatedly sounded, when within parameters.
Indeed

Sidestick ND - stall warning on
Sidestick NU - stall warning 0ff

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Old 13th Aug 2011, 08:55
  #1991 (permalink)  
 
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Originally Posted by jcjeant
This is a judiciary investigation under progress ..
They will have the FDR data .. so it's not left in BEA and Airbus hands only.
As Airbus have them, why not the victim's families ... ?


Originally Posted by HM
And as before, pretty well every post of mine will point to the sidestick culture.. so many downsides and the more we look at this (admittedly strange& hopefully rare) accident the more one can't imagine it ever happening with a fully visible and centred control device... whatever that may be.
Amen.
Now, would you expect any FINDING in such line of thought in the Final Report ?


Diversification and A33Zab,
Thanks for your documented replies.
Nevertheless, let me quote the D-AXLA report on P92 :
When the real angle of attack increased, the blockage of AOA sensors 1 and 2 at similar values caused the rejection of the ADR 3 anemometric values
In the AF447 case, there is an open door for ADR 1 anemometric values rejection.


Other BEA omission :
As initially reported by A33Zab.
And as further questioned later on.

Anyone ?
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Old 13th Aug 2011, 09:13
  #1992 (permalink)  
 
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It did not last long enough, only few 10th of second, as it was due to very short flight spikes exceeding alpha treshold.
IMHO, if that is the modus operandi then it needs looking at too..

Any 'spike' triggering the Stall Warning, should ensure that it sounds for a minimum time. (say 1 or 2 seconds) OR continue until AoA is below a preset delta below trigger point (say, 1/2 degree above 20,000 ft and 1 degree below)
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Old 13th Aug 2011, 09:48
  #1993 (permalink)  
 
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Lyman / HarryMann

I am not the right person to comment, having not been in a real high altitude aerodynamic stall since 1967 (not a passenger airliner, I hasten to add!), but stall recovery should never be considered an absolute given with a VSI of minus FLT100 per minute. The pilots had to both get the ND (the THS?) and not lose all control of the aircraft in the process. Never a certainty, even if the stall had been diagnosed in time. The critical period was shortly after A/P disconnect, to maintain stable flight and avoid the stall in the first place.
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Old 13th Aug 2011, 11:03
  #1994 (permalink)  
 
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Originally Posted by JD-EE
Military pilots may last a lot longer than transport pilots.
Isn't it the opposite happening already ... ?
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Old 13th Aug 2011, 11:06
  #1995 (permalink)  
 
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CONF iture

An issue limited to reconnaissance flights, particularly unmanned drones these days. That is an issue going back beyond Francis Gary Powers. There will be fighter jet pilots for a long time......
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Old 13th Aug 2011, 13:05
  #1996 (permalink)  
 
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Combat UAV(UAS) and Simulation vs Reality

An issue limited to reconnaissance flights, particularly unmanned drones these days. That is an issue going back beyond Francis Gary Powers. There will be fighter jet pilots for a long time......
Google Combat UAV and you will find that the long time may be a shorter time than one would think. The costs involved with keeping a pilot on the aircraft in terms of maneuverability (g limits) and environmental support cooling/heating/pressurization/protection of the cockpit are very large. There are already trials of air refueling combat UAVs, carrier landings with combat UAVs. But remember, these are rarely 'pilot-less' robot aircraft they are remotely piloted FBW aircraft with the pilot sometimes in a different continent so these fighter pilots will be around just not in the same place as the aircraft. A comfortable position to be in that allows the pilot to take more risks and walk away from every hull loss.

Simulation vs Reality

This raises a human factors issue on AF447 and training that I have not seen raised.

Simulations are used for training of all sorts of exigences there is no-one I know that has got into a simulator check ride where it is a boring flight and everything goes smoothly. It is expected that emergencies and failures will be exercised purely because they are not exercised 'in real life' - the raison d'etre of the simulator industry. This mentally sets up the trainee to expect problems in sim rides - and not to expect any emergency in the thousands of hours of mundane real world flight. There is a huge mental difference between being in a nice safe simulator exercise trying to please the training team behind you and being in a real world aircraft that has suddenly started an unscripted series of alarms and instrument failures knowing that your life is on the line -- or perhaps not fully understanding that your life is on the line.

I like many military pilots was fortunate (?) to be trained in an era when simulators were unreal and extremely expensive and actual flying was considered cheap. So all real emergency handling practice was carried out in real aircraft with imaginative instructors causing the emergencies. Instrument recovery from unusual positions was carried out from under a 'hood' with a 'you have control' midway through a high g aerobatic sequence - multiple times an hour. The trainee was in a REAL aircraft and having to do REAL recoveries.

The mental shock of a 'simulator exercise' suddenly happening in real life can lead to all sorts of human factors issues - some people who are good in simulated practices go to pieces in real life. Its a little late to learn that when the AP drops out with the wrong PF.

There could be a need for some kind of psychological assessment for FBW pilots. Or, more likely, even if the bean counters wouldn't like them, the old methods of using small aerobatic training aircraft to assess pilots were the right ones.
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Old 13th Aug 2011, 13:10
  #1997 (permalink)  
 
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HarryMann:

Seems a naive viewpoint to me...
It's not naive at all. Plenty of aircraft have very unpleasant stall/departure/spin characteristics, which no-one in their right mind would want to explore outside a very carefully managed flight test environment. That isn't to say they can't be operated safely, just that their pilots need enough warning to be able to stay away from the stall in the first place.

I personally believe the instumentation is extremely poorly conceived... position error should be minimised 'by physical design' not using PE corrections (e.g. probes far fwd away from pressure field around wing or fuse, as in test fl;ight a/c).
Actually the engineers designing these aircraft aren't stupid, and go out of their way to position static sources where the inherent pressure error is at a minimum over the normal flight envelope of the aircraft - those probes and static plates aren't where they are for convenience. Sure you can do better with a massive probe on the nose or trailing a static cone from the fin (or presumably several for redundancy ), but why got to all that trouble and expense when you can get acceptable accuracy by applying corrections for AoA etc?
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Old 13th Aug 2011, 13:11
  #1998 (permalink)  
 
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Originally Posted by TJH
An issue limited to reconnaissance flights
Almost ...
Pakistan: 4 morts dans un bombardement de drone américain
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Old 14th Aug 2011, 23:29
  #1999 (permalink)  
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Thread #6 continues here
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