What happened
On 1 May 2011, a Flight Design CTSW, registration G-CTSW, was performing a private flight from a private airstrip located in Killeter, Northern Ireland. The aircraft had been operated from the same grass runway over the previous two days without issue. On the day of the accident, the runway surface was damp due to overnight dew, though wind conditions remained consistent with previous flights.
During the takeoff roll, the pilot applied full power. The aircraft lifted off slightly further down the strip than had occurred during previous departures. Following liftoff, the pilot noted that the engine appeared to be producing low power and the aircraft was struggling to climb. Despite these performance concerns, the pilot continued the takeoff attempt. The aircraft failed to clear a boundary hedge at the end of the runway. Upon impact, the main landing gear struck the hedge, causing the aircraft to overturn into an inverted position in a nearby field. While the pilot escaped the wreckage uninjured and able to exit via the left door, the aircraft sustained extensive damage due to a post-accident fire.
The investigation
Investigators examined the environmental conditions and the aircraft's performance during the departure. It was noted that the pilot had experienced a lack of climb capability immediately following liftoff. The investigation also considered local topography and wind patterns, specifically noting that a ridge near the airfield could influence airflow.
Findings
- The aircraft's takeoff roll was longer than usual, with liftoff occurring further down the runway strip.
- The pilot experienced a perceived lack of engine power and difficulty maintaining a climb.
- The aircraft was likely affected by a wind rotor triggered by the crest of a nearby ridge, which was positioned slightly upwind of the runway's far end.
- This assessment was supported by reports from another pilot who encountered a strong rotor immediately after departing the same field.