This document covers the procedure for testing an Airmaster microswitch located inside the propeller hub. It is recommended that all microswitches are tested if an issue is suspected.
Symptoms of a failed microswitch may include open circuit alarms (all lamps flashing red on the controller), improper operation of the adjustable pitch limit stops, or anomalous indications displayed by the controller. Defective microswitches must be removed from service and replaced with new parts from Airmaster.
Microswitch Assy Inspection 
