Patent ID: 6583733
Filing Date: 2003-06-24
Classification: B64D,G01C,G05D

Abstract:
An apparatus for alerting a pilot of a rotary wing aircraft of proximity to terrain comprising:an input coupled to receive a first signal indicative of one of a low altitude mode of operation or a normal mode of operation, and coupled to receive signals indicative of a position of the aircraft, a flight path angle of the aircraft and a speed of the aircraft; an output; a signal processor, coupled to said input and to said output, for: defining a normal mode terrain protection envelope as a first function of the flight path angle, a look ahead distance, and a terrain floor boundary; defining a low altitude mode terrain protection envelope as a second function of the flight path angle, a second look ahead distance and a second terrain floor boundary, and wherein said second look ahead distance comprises a third function of a distance to transition from a first phase of flight to a hover phase of flight and wherein said terrain floor boundary comprises a fourth function of an aircraft altitude and said speed; selecting a current protection envelope from one of said normal mode terrain alerting protection envelope or said low altitude mode terrain alerting protection envelope according to said first signal; and outputting an alert signal when a subset of the stored terrain information is located within the boundaries of said current protection envelope.