What happened
On 30 September 2007, a Dyn’Aero MCR01 Club, registration F-PYMD, departed from Fridd Farm Airstrip in Kent for a private flight to France. Shortly after takeoff, the aircraft experienced a partial loss of engine power. The pilot attempted to return to the same airfield to land on Runway 32. However, the approach was conducted with a tailwind and a downslope, making the aircraft too fast to stop before the end of the runway.
An attempted go-around failed due to insufficient engine power. The aircraft descended into a field beyond the runway, striking a large oak tree. The impact caused the right wing to separate from the airframe and disrupted the passenger-side cockpit structure. The passenger sustained fatal injuries, while the pilot suffered serious injuries.
The investigation
The investigation examined the engine, the airframe, and the cockpit restraint systems. Investigators found that the engine's right carburettor main fuel jet had been blocked by a fragment of corrosion. Analysis of the carburettor bowl revealed high concentrations of chloride and bromide ions, suggesting chemical contamination from a cleaning solution had initiated corrosion in the presence of moisture.
Regarding the cockpit, while the seat harnesses remained intact, the attachment point for the passenger's shoulder harness had failed. The investigation determined that the bonding area on the fuselage was misaligned, meaning the forward edge of the fitting was bonded to a surface that had not been properly prepared. This weakened bond failed under the loads of the impact.
Findings
- The primary cause of the power loss was the blockage of the right carburettor main fuel jet by corrosion products.
- The corrosion was likely initiated by chemical contamination (chloride and bromide ions) within the carburettor bowl.
- The passenger's fatal injuries were exacerbated by the failure of the shoulder harness attachment, caused by an inadequate bond between the fitting and the fuselage due to misalignment and improper surface preparation.
- The pilot's decision to return to the same runway, despite the presence of a tailwind and downslope, contributed to the inability to stop before the end of the runway.
Safety action
- Safety Recommendation 2008-029: It is recommended that ROTAX introduce a requirement into the engine maintenance schedule for the 912 series to periodically remove and inspect carburettor bowls for moisture and contaminants.