Hughes 369D crash near Bel Air, Maryland, United States

A loss of engine power due to bearing failures in the turbine section resulting from a fatigue fracture of the oil supply line that fed oil to the Nos. 6 and 7 bearings. The oil line failure led to rapid deterioration of the bearings from oil starvation. Contributing to the power loss was the installation of a No. 8 stationary seal with an undersized outside diameter, which resulted in a reduction of support for the turbine section rotating components and resulted in high vibration loads in the engine, which ultimately caused the oil supply line to fatigue and fail. Also contributing was the improper or inadequate inspections of the No. 8 stationary seal by maintenance personnel.