Reply To: Trim in the PMDG NGX

[Diego Bürgin]

Thank you Jacques and John for the links.
I’ll be reading through those documents.

It may be that I misunderstand the term reversibility in regards to aircraft.

My current understanding of the controls is as follows:
– Controls big aircraft with fly by wire are not physically linked to the control surfaces and therefore not reversible.
– Controls in the 737 are physically linked to the control surfaces and therefore reversible,
BUT forces are too great, therefore hydraulics neutralize the control surface forces completely and add artificial forces as feedback.
– If all hydraulics fail in the 737, the pilots can move the control surfaces with the yoke, but both pilot and copilot have to exert extreme forces to move the controls.

My understanding about trim:
Stab trim:
– Rotates the whole stabilizer.
– Changing stab trim does not move the yoke.

Elevator trim:
– Rotates the little tab on the end of the elevator.
– MACH TRIM is automatically applied to elevator trim.
– Changing elevator trim moves the yoke.

Again, please correct me if I’m wrong.

Best regards
Diego