What happened
On 20 June 1998, an Auster 5, registration G-APRF, was conducting a private flight from Breighton Airfield to Sywell. Due to encountering deteriorating weather and strong headwinds, the pilot diverted to Netherthorpe Airfield in Nottinghamshire, a location familiar to the commander. After a four-hour delay for lunch and a period of weather clearance, the aircraft was refuelled and prepared for departure.
The takeoff took place from a 488-metre grass runway. Conditions at the time of departure included no wind, a temperature of 23°C, and wet grass following recent rain. Following standard engine and system checks, the pilot applied full throttle. While the tail lifted at a lower-than-normal speed, the aircraft failed to continue accelerating despite the engine appearing to run normally.
Recognising that takeoff was not possible, the pilot closed the throttle and applied the brakes, though he avoided maximum braking pressure to prevent a potential nose-over on the slippery surface. To avoid an obstacle at the end of the runway, the pilot applied power to clear a hedge, eventually landing on a road before the aircraft came to a stop in a field of rape. There were no injuries to the two occupants.
The investigation
The AAIB examined the circumstances surrounding the loss of acceleration. The investigation noted that the aircraft was within its maximum permitted weight limits. The pilot reported that the engine response appeared normal during the initial application of power, but the aircraft's forward momentum ceased unexpectedly.
Findings
- The aircraft experienced a loss of acceleration during the takeoff roll.
- The takeoff occurred on a wet grass surface with high humidity and warm temperatures.
- The pilot suspected that carburettor icing had occurred due to the high humidity and recent rainfall.