What happened
On 4 August 2019, a Jodel D112, registration G-BRCA, was conducting a private flight departing from Marsh Hill Farm Airstrip. Shortly after takeoff, the pilot became aware that his vehicle had been left unlocked with the keys visible, prompting a decision to return to the airfield to secure the car.
While leveling off at 600 ft to position for a landing, the pilot briefly engaged the carburettor heat but switched it back to the off position during the final approach. As the aircraft crossed the threshold hedge, it began to sink. The pilot attempted to increase power to compensate for the descent, but the engine failed to respond with its usual speed. Consequently, the aircraft made a very hard landing and bounced off the runway into the adjacent crops. There were no injuries to the pilot or the passenger, though the aircraft sustained substantial damage.
The investigation
The AAIB examined the circumstances surrounding the engine's delayed response. The investigation noted that the engine might not have been fully up to operating temperature at the time of the incident. Furthermore, investigators looked into the possibility of carburettor icing, noting that the pilot had only applied carburettor heat for a brief duration. Environmental data from nearby Oxford Airport indicated a temperature of 20°C and a dew point of 16°C, conditions which were identified as being conducive to serious icing during descent power settings.