PPRuNe Forums - View Single Post - AF 447 Thread No. 5
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Old 21st July 2011 | 12:26
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Lonewolf_50
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airtren
What's this supposed to mean?
It means I better understand what you were telling me about how you experienced the altitude change.

The BEA text does not mention manual power/throttle changes during the climb time interval from FL350 to FL375. So, that makes the climb unintentional?
That would be my assessment.
Typically, when you undertake a climb, you change both power and attitude. (Or is that now taught differently? It's how I used to teach a climb ...)

Caveat: some have suggested that the PF thought he had an overspeed, based on display anomalies, so perhaps he thought to trade airspeed for altitude. Hard to say.

I don't think a type rated pilot at that altitude would (given the small window of suitable speeds) purposefully bleed off his airspeed to climb 3000 feet. I am of the opinion that a rated pilot would do as pilots are trained to do from day one: he'd use power and pitch attitude to perform a climb. Note, he'd been intending to climb earlier, as evidenced by their discussing why they could not climb yet due the temperatures not being suitable for an altitude change.

So yes, airtren, I am of the opinion that he climbed unintentionally. Granted, if his gauges showed a high airspeed, and an altitude less than FL 350, assigned altitude, you could argue that a stick only altitude correction (and airspeed correction) would be the response. (But wait, if you are in bumpy/turbulent air, you usually hold an attitude, you don't chase airspeed, nor altitude.)

Back to my old question: what did he see?
JD
Rolling the plane to the left with up elevator is, I believe, a left turn input. If I'm right why'd the plane go into a fairly tight right turn?
Or, left wing up, nose up, is a correction to a right wing down, nose low, attitude. Whence that attidude? Not sure, but I find A33zab's post of interest.
A33zab
The MLA becomes active when the side stick is pulled more than 8°, and the load factor is more than 2g, in which case:

- The ailerons are deflected symmetrically upwards:
Max 11° added to Roll demand, if any.
-Spoiler 4,5 & 6 are symmetrically deflected:
Max 9° added to Roll demand, if any.
- Deflection is proportional to load factor in excess of 2g.
With the above in mind, is there a good reason to believe that AF 447 experienced a g load > 2g? (Does this take us to intermittent and substantial updrafts and down drafts? They did expect to hit some turbulence,)

To follow that thought, are you suggeting a possible malfunction or degradation of the MLA function you spelled out?
(Hence, PF having to correct a roll in Alt Law ...)

If this happened, might it have left no audit trail in ACARS or FDR?

Last edited by Lonewolf_50; 21st July 2011 at 12:59.
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