Report on serious aviation incident at Skjetten in Akershus county, Norway on 20 January 2024 involving an Aquila AT01, LN-NRC

All engine instruments showed normal values ​​before departure from Kjeller Airport on runway 30. When the aircraft crossed the Nitelva River, the pilot noticed a reduction in power. Immediately afterwards, there was a "clank" and the propeller stopped. The pilot turned left and landed on a snow-covered field. The pilot recived minor injuries.

A review of the oil system revealed no signs of oil leakage and all the oil was found in the oil tank. No faults were found with the oil pump.

The meteorological station at Kjeller registered between -28 and -29 degrees Celsius during the period before the flight began. The investigation has revealed that the aircraft and engine documentation does not provide a clear picture of temperature limitations for the end user.

The NSIA believes that it is likely that a combination of cold temperatures and the choice of engine oil led to the oil system before the oil pump not being able to to deliver enough flow, causing cavitation in the oil pump. This reduced the oil pump's efficiency, which led to loss of lubrication and bearing failure. The NSIA believes that the design of the preheating system helped to mask the problem from the pilot, as a situation may have arisen where the engine received enough oil during ground operaiton but not at high power output during takeoff.

Published 19.02.2025