Sundstrand Data Control, Inc.

John H Glover

Hans R Muller

Noel S Paterson

A warning system for rotary wing aircraft that monitors the altitude above ground of the aircraft and issues a warning when there is insufficient terrain clearance. The warning criteria are optimized for rotary wing aircraft and are altered as a function of landing gear position and airspeed. Two distinct warnings are given. One indicates insufficient terrain clearance and the other warns the pilot if he attempts to land with the landing gear up. Logic circuitry is provided to modify the criteria necessary to generate a warning, and to inhibit certain warnings, as required by the mode of operation of the aircraft.

Warning system for tactical rotary wing aircraft

A wind shear detection and alerting system (30) compares inertially derived accelerations with air speed rate to provide a wind shear warning signal. Inertially derived accelerations are used instead of purely inertial accelerations because purely inertial systems generally require a vertical gyro. By utilizing angle of attack (.alpha.) and flight path angle (.gamma.) instead of pitch angle (.theta.) in the calculation, no vertical gyro signal is required and the system will be responsive to vertical as well as horizontal shear conditions. An enhanced version of the system is also compensated for roll angle (.phi.), with the roll angle being derived from the rate of change of heading (.PSI.) to avoid the need for a vertical gyro. The alerting system is capable of providing visual and aural warnings for a variety of wind shear conditions, such as, head shear, tail shear, head shear followed by tail shear and wind shear trend. The waring system is also capable of providing a wind shear warning which is a function of the radio altitude of the aircraft.

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Kirkland, WA, United States of America

John H Glover