What happened
On 13 December 2014, a Cessna 208B, registration N208B, was attempting a private departure from Brittas House Airfield in Co. Limerick, bound for the United Kingdom. During the takeoff roll on a wet, grass runway, the pilot noted that the aircraft was not accelerating at the expected rate. Despite applying maximum engine power, the aircraft failed to reach the necessary speed for a safe liftoff.
Realizing that the aircraft could not stop safely before the end of the runway without entering a deep ditch, the pilot attempted to overfly the obstacle to reach an adjacent field. During this maneuver, the aircraft struck fence posts, causing substantial damage to the fuselage, tailplane, and engine components. The pilot was able to exit the aircraft without injury.
The investigation
The AAIU investigation focused on the aircraft's performance and the pilot's decision-making process. Investigators examined the aircraft's configuration and found that the wing flap selector lever had been left in the FULL position. This setting had been used during the pre-flight inspection to check the flap mechanisms but was not reset to the 20-degree takeoff setting.
Technical analysis of the aircraft showed that the engine and propeller were in good working order, with no mechanical failures contributing to the loss of power. The investigation also reviewed the runway conditions, noting that while the surface was wet and muddy in places, the primary issue was the aerodynamic drag caused by the incorrect flap setting. The pilot's weight and balance calculations were also confirmed to be within safe limits.