What happened
On 28 May 2017, a Eurofox 912(IS), registration G-ODGC, was operating as a glider tug near Puddletown, Dorset. During the launch of a glider, the aircraft's Rotax 912 IS Sport engine ceased operation at an altitude of approximately 300 ft. The aircraft had already commenced a right-hand turn at 150 ft.
Following the engine failure, the pilot released the glider's tow rope and continued the turn to return to the airfield. Despite making two separate attempts to restart the engine, the pilot was unsuccessful. As the aircraft approached the airfield boundary, the right wing struck a tall shrub, causing the aircraft to spin. The aircraft eventually came to rest backwards in long grass. The pilot escaped the incident with no injuries, though the aircraft suffered damage to the propeller, landing gear, rear fuselage, fin, and rudder.
The investigation
The investigation focused on the engine failure and the subsequent restart attempts. The aircraft had recently undergone an engine upgrade, replacing a carburetted engine with an electronic fuel injection model. This new engine required a specific restart procedure, including the activation of a "backup battery" that is typically turned off after the initial start. The pilot noted that they had omitted this specific checklist step during the time-pressured restart attempts.
Technical inspections of the engine were conducted at a repair facility. Investigators discovered debris within the fuel pressure regulator and the fuel filters. While fuel tests revealed elevated levels of silicon, there was no conclusive evidence that this contamination or the presence of debris was the direct cause of the engine stoppage. Additionally, the pilot observed that the main fuel valve was not in a fully vertical position following the crash, though this may have been a result of the impact.
Findings
- The engine stopped during a climb while performing a glider tow operation.
- The pilot failed to follow the specific restart checklist required for the electronic fuel injection engine, specifically regarding the backup battery setting.
- Debris was identified within the fuel pressure regulator and fuel filters, although its role in the engine failure could not be confirmed.
- The pilot's decision to continue the turn back to the airfield resulted in an excursion beyond the airfield boundary, but the pilot successfully prevented an aerodynamic stall.