What happened
The pilot-in-command reported that the aircraft engine began to run roughly, accompanied by fluctuating fuel flow. In an attempt to resolve the issue, the pilot switched to an alternate fuel tank, which temporarily smoothed out the engine operation. However, upon switching back to the original fuel tank, the engine oil pressure dropped to zero and significant vibration resumed. Recognizing the severity of the mechanical failure, the pilot elected to shut down the engine and execute a forced landing.
The investigation
A subsequent examination of the aircraft revealed that the engine oil pump was functioning correctly and that there was a sufficient quantity of oil within the engine system. Despite these normal mechanical conditions, investigators discovered water contamination present in the fuel injector distributor, which likely caused the erratic engine performance and subsequent failure.