DG-1000T loses its sustainer propeller to a coupling bond failure
Climbing on its sustainer near Weston-on-the-Green, a DG-1000T lost the propeller when the drive coupling failed; both occupants were unhurt and the departing propeller lightly damaged the fuselage and left wing. A loud bang and an overspeed warning signalled the propeller had gone; the pilot closed the throttle, shut off the ignition, retracted the engine and landed safely. The coupling had separated through its rubber element: the drive-side surface roughness needed to bond the rubber to the aluminium had not been achieved, and there were no inspection criteria for the finish. The manufacturer has changed the coupling.
- Sustainer deployed to climb: On a local flight the pilot deployed the DG-1000T's sustainer engine to gain height.
- Propeller detaches in flight: A loud bang and an engine overspeed warning signalled the propeller had detached from the drive.
- Coupling bond had failed: The drive coupling had separated through its rubber element; the surface roughness needed to bond it to the aluminium had not been achieved, with no inspection criteria.
- Engine stowed, safe landing: The pilot closed the throttle, shut off the ignition, retracted the engine, confirmed control and landed safely.
- Minor airframe damage: The departing propeller lightly damaged the fuselage and left wing; both occupants were unhurt. The manufacturer has changed the coupling.