ALT-STAR Mode

ALT-STAR is the altitude transition, aquisiton and capture mode. The 
computer calculates speed versus time in order that it may cause
the aircraft to smoothly transition to and hold the altitude that
is set in the glareshield.

The method is to reference the vertical speed and altitude when 
this mode comes online taking into account airspeed, vertical speed
rate.

The computer then commands the THS (trimmable horizontal stabilizer) to fly
the vertical speed schedule, taking into account the starting
altitude and calculating when to begin the level off. This mode
assumes the autothrottle will provide thrust as necessary to
maintain airspeed. 

Initially, no restrictions were included,
but now, AOA (angle of attack) protection is within
this mode's logic.