SE7510696L - GROUND PROTECTOR FOR AIRCRAFT - Google Patents

Abstract

1479082 Aircraft warning indicators SUNDSTKAND DATA CONTROL Inc 26 Sept 1975 [3 Oct 1974] 39458/75 Heading B7W An aircraft ground proximity warning system comprises means for combining, according to predefined criteria, a signal hÀ R representing the aircraft's rate of change of altitude over the ground and a signal hÀ R representing the aircraft's altitude over the ground to generate a warning signal 26 indicating the aircraft's approach to the ground, and speed compensating means V A for varying said predefined criteria as a function of aircraft speed to advance the generation of the warning signal with increased aircraft speeds. A signal hÀ R representing aircraft altitude above ground and a signal hÀ B representing aircraft barometric altitude are respectively differentiated by rate circuits 14 and 16, one to produce the signal hÀ R and the other to produce a rate signal hÀ B . The signal hÀ R is fed to a rate limiter 18 the output hÀ RL of which is fed to a filter 20 which receives also the rate signal hÀ B . The combined altitude rate output hÀ C is compared in a summing junction 24 with the altitude above ground signal hÀ R and whenever the output of the junction 24 is positive the alarm signal 26 will operate. To ensure that the warning time will be shortened with increased aircraft speed the rate limiting circuit 18 is controlled by an input on line 38 which is a function of air speed VÀ A , thereby increasing the limiting amplitude of the signal h R as a function of aircraft speed. A circuit is described (Fig. 5, not shown) for increasing the rate limitation within rate limiter 18 and this is subject to a signal from a landing gear sensor 54 which imposes a limitation on the amplitude of the hÀ R signal when the undercarriage is lowered.