The Garrett Corporation

Glenn A Burgess

Clarence T Yamanaka

Howard P Aldrich

Paul Taylor

John B Lippold

Paul P Wong

This invention controls the air pressure in an aircraft cabin in response to a selected landing field altitude and to a selected maximum permissible cabin pressure rate.

Aircraft cabin pressurization system

An aircraft cabin pressure control system regulates cabin pressure as a function of outside ambient pressure in accordance with the equation ##EQU1## WHERE K.sub.1, K.sub.2 and K.sub.3 are constants, P.sub.a is atmospheric pressure, and P.sub.c is the desired value of regulated cabin pressure.

Control schedule linearization system

An excessive rate of change of cabin pressure detection system used in conjunction with a cabin pressure controller monitors changes in cabin pressure. Whenever the rate of change of cabin pressure exceeds a preselected level, an output is produced which may provide a sensory warning. In a dual controller system, the signal is utilized to switch control of cabin pressure to the standby controller.

Excessive rate detection system

A cabin pressure control system has two independent controllers, one of which is the primary controller and the other the standby controller taking control in case of primary controller malfunction. The controllers switch roles automatically each flight. An annunciating system indicates the identity of the primary controller on the previous flight and maintains the designation in case of malfunction so that a defective unit may be readily identified.

Mode indication system

In a cabin pressure control system utilizing dual controllers, one of which is in primary control of cabin pressure and the other of which is standby, external pressure and cabin pressure are monitored. If the difference exceeds a predetermined safe value, the rate of change of cabin pressure is incremented based on the excess. Also, switching of control from the primary to secondary controller, as would occur upon malfunction, is prevented.

Pressure differential system

A cabin pressure control system for an aircraft in which the controller provides control signals to an outflow valve by way of a pneumatic amplifier relay means, has the memory or rate chamber of the controller providing the pneumatic signal to the relay instead of the usual case where the signal comes from the reference pressure chamber. Any one of several forms of relays may be used in this novel system. One form of relay includes a feedback signal from the outflow valve.

Growing community of inventors

Downey, CA, United States of America

Glenn A Burgess