Hi jimjim1,
Originally Posted by jimjim1
The computer would have matched the manual THS movements with elevator movements to exactly compensate so that aircraft g (pitch) was maintained.
It is not correct. THS do not replace elevators control and elevators are not used to replace THS trim.
(In flight phase) The C* law is activated. It combines the elevator control and the THS controls (AUTOTRIM function). It generates a load factor demand as a function of the position of the side sticks and inertial feedbacks. The gains depend on the speed (Vc) and center of gravity.
Consequently, any large change of pitch is not compensated by THS change and longitudinal stability is maintained. Moreover, in alternate law, C* law gain is reduced, hence 1g is not maintained "at all cost", and certainly not when the sidestick is moved back and forth.
Originally Posted by rudderrudderrat
I can't find any reference to that - it would appear to be in error.
See yourself:
THS control
The elevator orders are progressively transferred to the THS through a low-speed integrator to decrease the drag. This is the AUTOTRIM function. The THS movement is inhibited:
- under 50 ft in manual mode (100 ft in AP mode),
- when the high-speed and Mach protection is active,
- in case of manual action on the hand wheel,
- when the load factor is lower than 0.5 g,
- in case of abnormal condition law.
The THS movement is limited in up direction:
- when the alpha protection is active,
- when the load factor is higher than 1.25g,
- when the bank angle is above 33 deg,
- in case of low speed protection (alternate law).