Summary
We propose to adopt a new airworthiness directive (AD) for Hartzell Propeller, Inc. propeller models HC-(1, D)2(X, V, MV)20-7, HC- (1, D)2(X, V, MV)20-8 and HC-(1, D)3(X, V, MV)20-8. This proposed AD was prompted by failures of the propeller hydraulic bladder diaphragm and resulting engine oil leak. This proposed AD would require replacement of the propeller hydraulic bladder diaphragm. We are proposing this AD to prevent propeller hydraulic bladder diaphragm rupture, loss of engine oil, damage to the engine, and loss of the airplane.