What happened
On 26 June 2018, a Cessna 414, registration N414FZ, was conducting a private flight from Enstone Airfield in Oxfordshire. During the initial takeoff roll, the left engine failed, causing the aircraft to veer and come to a halt on the runway. The pilot attempted to restart the left engine, during which time the right engine also stopped. After several attempts, the left engine eventually restarted, and the aircraft proceeded to take off again.
During the subsequent climb in a right-hand turn, the right engine lost power. The pilot managed to level the aircraft and briefly restored power to the right engine by using the auxiliary fuel pump. However, while attempting to return to the airfield, the right engine failed again. The pilot feathered the propeller but found that the single-engine performance was insufficient to maintain altitude or maneuver effectively. Unable to reach a designated landing field, the pilot attempted a forced landing in a nearby ploughed field, but the aircraft struck farm buildings at a poultry farm. The resulting fire destroyed the aircraft and part of the farm buildings, causing one minor injury to the pilot and one serious injury to the passenger.
The investigation
The AAIB investigation examined the aircraft's maintenance history, fuel system, and performance capabilities. The investigation noted that while the engines had been modified by RAM Aircraft to increase horsepower, there was no evidence that the engines were still capable of achieving that increased performance. The investigators also reviewed the aircraft's fuel system, which featured a complex arrangement of main and auxiliary tanks and pumps.
Findings
- The most likely cause of the successive engine failures was a disruption in the fuel supply between the fuel tanks and the engine fuel control units.
- The aircraft's single-engine climb performance was likely lower than the pilot had calculated, as the engines were likely not producing the increased power from the RAM modification.
- The extended landing gear and the windmilling right engine further degraded the aircraft's ability to maintain altitude during the critical phase of flight.
- The intense fire at the crash site was caused by the aircraft's fuel rather than any external sources at the farm.