The Garrett Corporation

Howard P Aldrich

Glenn A Burgess

Clarence T Yamanaka

A cabin pressure control system has two independent controllers, one of which is used as primary controller while the other serves as standby. On alternate flights the identity of primary and standby controller are switched so that both controllers will be regularly utilized.

Control alternating 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

In a cabin pressure control system having primary and standby controllers, control is switched from the primary to standby upon occurrence of a malfunction which prevents the primary controller from maintaining pressurization properly. If failure is a result of insufficient inflow of pressurized air of excessive leakage, transfer is prevented and the problem is annunciated to the crew.

Flow annunciation 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.

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Rancho Palos Verdes, CA, United States of America

Howard P Aldrich