What happened
On 19 February 2023, a Cessna F172N, registration EI-GWU, was performing a takeoff from Runway 18 at Birr Airfield, Co. Offaly. The flight was a general aviation training session involving an instructor and a pilot with no prior experience on this specific aircraft type.
As the aircraft accelerated down the runway, the instructor noticed that the engine sound was quieter than usual and the aircraft was not accelerating as expected. The airspeed had stagnated between 50 and 55 knots, and the engine was not developing full power. Recognizing the danger, the instructor ordered the takeoff to be abandoned. The pilot closed the throttle and applied the brakes, but due to the wet grass surface, the aircraft could not stop in time. The aircraft overran the end of the runway and struck a boundary hedge. There were no injuries to the two crew members, though the aircraft sustained minor damage to the propeller, cowling, and nose wheel.
The investigation
AAIU investigators examined the aircraft's engine performance and the environmental conditions at the time of the incident. A subsequent ground run by a maintenance engineer showed that the engine operated normally, with no anomalies found in the ignition or power settings.
Investigators also reviewed the meteorological data, noting that the temperature was 9°C with a dew point of 7°C. Furthermore, the investigation looked into the procedures used during the pre-takeoff power checks. While the pilot had applied carburetor heat for a few seconds during the checks, the investigation focused on whether sufficient measures were taken to prevent ice buildup in the induction system.