SpannerKL
Thanks for your input however are you sure that this is active? Re-reading my copy of `Handling the Big Jets` page 266 where DP Davies the then CAA Chief Test pilot discusses the B747 certification flying programme he says that the Stab Trim Brake mechanism was made to be compatible with a Mach Trimmer however that was deleted from the final design. Also the flighdeck has no such controls and the MEL makes no mention of a Mach Trim system therefore I assume that it is not in fact installed. The aircraft exhibits a natural pitch-up at M0.94