What happened
On April 18, 2011, at approximately 15:20, a private pilot operating a Samba XXL (registration OK-OUA58) departed Warsaw Babice Aerodrome for a flight to Chrcynno. After performing a low pass over the runway at Chrcynno, the pilot returned to Babice and requested a landing on the grass runway.
During the initial approach, the pilot noted significant wind gusts. Despite attempts to use rudder and aileron to counteract lateral drift, the aircraft experienced heavy rolling to the left wing. The pilot decided to execute a go-around. During the second approach, the lateral instability intensified. As the pilot applied full throttle to initiate the go-around, the aircraft experienced a sudden roll to the left, causing the left wingtip to contact the grass surface. The aircraft slid along the grass, performing a 90-degree turn before settling parallel to the runway in the opposite direction of the intended landing.
Following the incident, the pilot successfully landed at Chrcynno and later returned to Babice, landing diagonally across the grass runway to account for the wind.
The investigation
The investigation examined the aircraft's configuration, the meteorological conditions, and the pilot's actions during the critical phase of the missed approach. The investigation reviewed the fuel distribution within the wing tanks, the pilot's weight and positioning, and the aerodynamic effects of the propeller slipstream and wind gusts.
Findings
- The primary cause of the incident was the sudden increase in engine power during a crosswind landing attempt, which led to a loss of control.
- Significant fuel imbalance existed between the wing tanks; the left tank contained 45 liters of fuel while the right tank contained only 7 liters.
- The pilot's weight (95kg) and position on the left side of the cockpit may have contributed to the lateral instability.
- The propeller slipstream, which naturally induces a leftward yawing tendency, was exacerbated by the rapid application of throttle at low speeds.
- The drag created by the left wingtip sliding along the grass surface contributed to a significant turning moment.