PPRuNe Forums - View Single Post - Malaysian Airlines MH370 contact lost
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Old 23rd Mar 2014, 17:46
  #7550 (permalink)  
Wizofoz
 
Join Date: Jun 2001
Location: Boldly going where no split infinitive has gone before..
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I do not know the 777, but I think I remember someone stated that there is an alternate law mode, which does not guarantee AoA prot .
There is no AofA protection on the 777 in NORMAL law- it's quite different to the Airbus in that respect.

With the autopilot off, you can stall the aeroplane just like a Cessna. It will stop trimming near the stall, but if you keep pulling on the Control Column, you can stall it.

I didn't read the whole post this was in response to, but if the suggestion is that with the crew incapacitated, and the engines flamed out, the aircraft would continue on Autopilot with the RAT, that is entirely incorrect.

Firstly, if there is a power interruption on both main busses, the aircraft reverts to secondary control mode, and the Autopilot will not engage in that mode.

Once power is restored, primary mode and therefore autopilot capability can be restored, but only by pilot action.

HOWEVER- the RAT only provides a small amount of AC to a load-shed system- the Autopilot is NOT available on RAT power only.

In the event of a double flame-out, the APU automatically starts- but if the reason for the flameout is fuel exhaustion, the APU wouldn't start either.

If the aircraft flew on Autopilot until it's fuel was exhausted with unconscious pilots, it would have then entered a simple attitude holding mode, and descended wings level but otherwise uncontrolled.
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