What happened
On 14 April 2014, a RANS S6-ES microlight, registration G-BZRA, was attempting to depart from a private grass airstrip in Cloongoonagh, Co Mayo. The aircraft, carrying a pilot and one passenger, was performing a takeoff from a runway approximately 280 to 295 meters in length.
Shortly after the aircraft became airborne, it lost its ability to climb. The aircraft subsequently descended into an adjacent agricultural field, which sat roughly 5 meters lower than the end of the runway. The impact caused substantial damage to the aircraft, including a distorted cockpit cage, a broken windscreen, and the failure of the engine bearer arms, which caused the engine to detach from the airframe. The landing gear sustained significant damage, with the nose wheel and starboard main gear legs shearing off. Despite the severity of the impact, there were no injuries to the two occupants.
The investigation
The investigation examined the aircraft's technical history, the airfield topography, and meteorological conditions. Records from the UK Light Aircraft Association (LAA) indicated that the engine performance had remained stable during annual inspections between 2009 and 2013.
Investigators analyzed the airfield layout, noting that the runway featured a hill approximately two-thirds of the way along its length. The terrain at the runway's end dropped away into a soft field. Meteorological data from nearby Ireland West Airport (EIKN) showed variable winds of approximately 3 to 6 knots during the period of the accident.
Findings
Several factors likely contributed to the aircraft's inability to maintain altitude:
- The aircraft was likely operating near its maximum permitted gross weight of 450 kg, as the two occupants weighed approximately 88 kg each.
- The aircraft may have encountered a downdraft caused by a shifting wind gradient or windshear as it passed over the hill.
- The pilot may have experienced a loss of ground effect; the aircraft likely lifted off while in ground effect at the top of the hill but lost this aerodynamic advantage before reaching a sufficient flying speed due to the descending topography.