B777 Alternate Pitch Trim
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Join Date: Dec 2001
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B777 Alternate Pitch Trim
When do you use the Alternate Pitch Trim levers on the B777?
Are they only used when the a/c is being flown in Direct Mode or are they also used in Normal and Secondary Modes?
Are they only used when the a/c is being flown in Direct Mode or are they also used in Normal and Secondary Modes?
Usual disclaimers apply!
Join Date: Nov 1999
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Alternate pitch trim levers Always have the highest priority as they are mechanically linked to the STCM's. Their primary function would be to control stab movement if the PFC's (elevator offload function) or the 'pickle' s/w's failed to do so, or command the stab to move if there was a failure of the 28vdc supply from the right and centre PSA's.
You could use them at any time BUT the stab would move at full speed. 0.5 deg/sec.
In direct mode you would still use the 'pickle' s/w's.
You could use them at any time BUT the stab would move at full speed. 0.5 deg/sec.
In direct mode you would still use the 'pickle' s/w's.
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Thanks for the reply gas path. Great explanation, especially when combined with your post on B777 fly-by-wire from last year.
