The pilot has over one minute before the GPWS sounds an aural warning. Since the MSA is 2000 feet above the mountainous terrain, the eminent danger is less then the other systems allow.
Over one half of all CFIT accidents occur on approach.
AMSADD is the only terrain awareness system that monitors your altitude and course to the runway threshold every 1/2 mile while in the airport area during precision or non precision approaches.
In this example, Ontario, California airport is shown on the AMSADD display. Since the aircraft has just entered the airport area, both runways are protected until the aircraft is closer to the runway intended for landing.
The aircraft is now at the FAF and the AMSADD system has automatically identified the runway for the approach based on aircraft position at the FAF.
The "CHECK ALTITUDE" display indicates that the aircraft has deviated from the correct altitude from where if should be during any part of the approach. This mode works for ADF, GPS, VOR, and ILS approaches. IMPORTANT....Anytime the aircraft drifts from the runway approach corridor, the AMSADD computer reverts back to the MSA (flight) mode and displays the MSA.
As the aircraft approaches the end of the runway, the AMSADD display goes blank in order not to be a distraction.
In the event of a missed approach or go around, the MSA display reverts to a "missed approach" mode. Once the missed approach has commenced and has left the airport area, AMSADD reverts back to the "take off" mode. When leaving the airport area, the "look ahead" feature is activated and the AMSADD system returns back to normal operation.
