Patent ID: 9120559
Filing Date: 2015-09-01
Classification: B64C

Abstract:
1. A propeller blade pitch actuation system comprising: a propeller control module (PCM) for adjusting blade pitch on at least one propeller blade; a PCM drain line connected to the PCM to drain hydraulic fluid employed in adjusting the propeller blade pitch; a first drain line downstream of the PCM drain line; a drain line restriction connected to the first drain line; a second drain line downstream of the PCM drain line; and a valve comprising a first valve position and a second valve position, the first valve position connecting the PCM drain line to the first drain line through the valve, and the second valve position connecting the PCM drain line to the second drain line through the valve; wherein hydraulic pressure of the first drain line between the valve and the drain line restriction is greater than hydraulic pressure of the second drain line.