Mach trim compensators trim the nose up to counter the effects of shock wave formation over the wings, right? So why is it that the B737 M. trim compensator kicks in at just above M .615 ?
http://www.b737.org.uk/flightcontrols.htm
Are there shock waves forming on all passenger aircraft's wings? I thought the wings would shock stall if local Mno exceeded 1.0? What am I missing here?