Incident Details
During a flight from Kununurra to Bellburn and the subsequent departure from Bellburn, the aircraft was initially reported by the pilot to be performing normally. However, an emergency began with a gradual degradation in engine performance, culminating in a forced landing. Throughout the emergency, the pilot observed that fuel flow was below normal while all other engine indications remained normal.
Pilot Actions
The pilot made an early decision to turn back to Bellburn Airfield. As the situation developed, the pilot quickly recognized the need for a forced landing. By turning into the wind and flying at the best glide speed, the pilot maximized the time available to manage the emergency and evaluate landing options. Additionally, the pilot utilized a supporting aircraft, which had the chief pilot on board, for troubleshooting advice. Although it could not be determined to what extent the pilot's recent forced landing practice influenced the sequence of events, it was likely that the practice reduced the risk of mishandling the emergency and may have prevented further injury to the occupants.
Investigation Findings
The Australian Transport Safety Bureau (ATSB) concluded that the missing air intake pipe was the cause of the loss of power. The reported performance of the aircraft was consistent with the likely symptoms arising from the air intake pipe to number six engine cylinder becoming loose and then detaching in flight. However, consistent with a previous occurrence in 2015, the reason for the air intake pipe coming loose could not be determined.