ATPL - The Mach trim system allows to:

Question id 198 - Aircraft General Knowledge - Instrumentation - ATPL - Airline Transport Pilot license

Search for the ideal CG location by transferring the fuel into the horizontal stabilizer.

Increase the longitudinal static stability of the aircraft by changing the horizontal stabilizer according to the Mach number.

Interlock the operation of the stick shaker at the oncoming of the high speed stall.

Trim the pitch-up tendency at a high Mach number.