What aircraft was involved and where did it happen?

The accident on 2010-02-15 involved a aircraft, at :, FR.

What was the probable cause of the accident?

The engine failure was caused by debris clogging the fuel pump suction valve due to a lack of adequate fuel filtration. The subsequent accident was caused by the pilot's failure to maintain directional control and airspeed following the engine failure, leading to an asymmetric stall and spin.

Engine failure leads to fatal ultralight crash in Normandy

A twin-engine ultralight aircraft crashed during initial climb near Granville, resulting in one fatality and leaving a passenger seriously injured.

What happened

On February 15, 2010, at approximately 9:25 AM, an Aviasud Mistral Twin ultralight, identified as 50-IK, crashed during the initial climb following takeoff from the Granville airfield in France. The aircraft, operated by an aerial work company, was performing a scheduled mission to count seabirds in the Mont-Saint-Michel Bay.

Shortly after departing the unpaved runway at 8:23 AM, the aircraft reached an altitude of approximately 50 meters when it experienced an asymmetric stall. The aircraft entered a spin and struck the ground on a nearby golf course, less than 500 meters from the grass runway. The impact occurred with a steep nose-down attitude, after which the aircraft settled on its landing gear. The accident resulted in one fatality (the pilot) and one serious injury (the passenger).

The investigation

Investigators examined the wreckage and determined that while the forward Rotax 532 engine was delivering power at the moment of impact, the rear Rotax 503 engine had failed. Eyewitnesses at the scene noted that the aircraft sounded quieter than usual and observed the rear propeller was stationary. The passenger recalled that the rear engine had stalled once prior to the taxi phase and had been restarted by the pilot.

Technical analysis of the electric fuel pump for the rear engine revealed that synthetic and organic debris, including plant fibers and a grass husk, were lodged in the pump's suction valve. This blockage prevented the proper intake of fuel. Furthermore, investigators found that there was no fuel filter installed between the fuel tank and the electric pump, which allowed these foreign objects to enter the fuel lines.

Findings

The primary cause of the engine failure was the inappropriate management of an engine failure during the critical phase of initial climb.
The pilot likely focused on the malfunctioning rear engine at the expense of maintaining flight path control, despite the forward engine having sufficient power to continue the flight.
The loss of power on the rear engine created a pitch-up moment and a reduction in airspeed, leading to the asymmetric stall and subsequent spin.
A contributing factor was the insufficient filtration of the fuel supply, as the lack of a filter between the tank and the pump allowed debris to reach the suction valve.
The lack of a stall warning prevented the pilot from detecting the onset of the stall.