Airframe 250 HRS TTIS

Engine 250 HRS TTIS

Following a one hour flight where no anomalies were found in the B/F inspection the aircraft was parked in the hangar. A very discernable tilt of the engine was observed when viewed against the hangar vertical columns.

A closer inspection revealed a complete collapse of both Left Hand engine mounts.

The left picture shows the L/H side Engine mounts viewed from front to rear. The rear engine mount bottom portion had totally collapsed and the front one had disintegrated but still in place.

The R/H side engine mounts were still serviceable.

Above is a view of the L/H front and rear engine mounts and a serviceable R/H engine mount. The spacer tube for the engine mount bolt is also pictured.

The engine mounts were replaced with spares held from another similar drifter.

I noted that the spacer tube from my spares were 12.55mm OD and a loose fit through the mount, whilst the ones I removed measured 13.09mm OD and a tight fit.

Likely analyses would indicate that either:

1. the neoprene compound was defective or affected by heat as both were in the vicinity of the exhaust.
2. Possibly, the increased OD of the spacer caused stressed in the material that caused it to peel back the way it did.

The rapid onset of the problem without prior warning signs is a cause for concern. Had it been a lengthy flight severe vibration would have been a likely outcome.