Pressure switches on proprotor swashplate actuators on 21 Bell Boeing V-22 Ospreys have been replaced after a manufacturing defect caused a hydraulic leak on a tiltrotor undergoing acceptance flight testing. The affected aircraft included three of the 10 US Marine Corps MV-22Bs scheduled for deployment to Iraq in September.
A machining flaw in the switch, supplied by Eaton Aerospace, allowed a seal to extrude through a gap with the piston, causing a hydraulic leak. Each swashplate actuator has two switches, for a total of 12 per aircraft, and 86 actuators were suspected to be affected, only 33 of which were actually in the fleet.
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