What happened
On 24 September 2014, an Aero AT-3 R100, registration G-DPEP, was conducting a routine local flight from Birr Airfield, Co. Offaly. During a standard approach to Runway 36, the aircraft experienced a sudden increase in lift, causing it to balloon and subsequently bounce off the runway surface.
As the aircraft became airborne again following the bounce, the pilot applied engine power in an attempt to arrest the descent. This application of power triggered a sharp yaw to the left. The aircraft then touched down in a nose-down attitude on the grass area situated to the left of the runway. The impact caused the nose landing gear to collapse and the propeller to strike the ground. The pilot, who was the sole occupant, escaped the wreckage without injury.
The investigation
The investigation focused on the aerodynamic forces acting on the aircraft during the low-speed phase of the landing. Investigators examined the interaction between the propeller slipstream and the aircraft's vertical stabilizer. The aircraft, which is powered by a Rotax 912S engine, features a clockwise-rotating propeller (as viewed from the cockpit).
Findings
- The aircraft sustained substantial damage, specifically to the engine firewall, the propeller, and the nose landing gear.
- The primary factor in the loss of directional control was the insufficient application of right rudder to counteract the leftward yawing moment.
- The application of power during the low-airspeed phase increased the slipstream effect on the vertical stabilizer, creating a sideways aerodynamic force that induced the leftward yaw.