Hi Bearfoil,
Originally Posted by Bearfoil
The FCOM alerts the operator to the THS preventing some PITCH authority above 180 knots? How is this alert benign to the efforts of PF447 recovering the a/c?
In fact, the FCOM is underlining that the aircraft "PITCH authorithy" is better than in "conventional aircraft". What is mentioned is about a very remote case: a fully "jammed" THS - without any manual or electrical trim available. Above 8 deg NU, elevators will still be effective below 180 knots: this is the limit speed mentioned for
safe flying in this case.
But now, do you think that AF447 had a jammed THS? Should I remember you that autotrim and manual trim were both very likely available. In fact, it seems that the main flight-control issue about AF447 "recovery" attempt, so far, was rather the complete lack of PF sustained nose down imputs...
Originally Posted by Bearfoil
Yes, I think elevators alone would have been preferred. Once above a certain angle, and at >180 knots, with All Trim Fuel aft, recovering seems a tall challenge?
By itself, "All Trim Fuel aft" means nothing... there is a variation from 0 to +0.5% aft of the target CG due to central tank fuel use which is completed by transfer from the THS to the central tank during cruise; add also a 2% safe margin below certification aft limits (if target is at max) and a push-button for forward fuel transfer, just in case.
Recovering from a stall without sustained nose down imputs seems rather quite more challenging than any "all trim fuel aft".