What happened
On April 9, 2023, a Boeing Stearman Model 75 was conducting a local flight involving aerial exercises near the Airport of Kortrijk/Wevelgem (EBKT). Following the maneuvers, the pilot returned to the airfield for landing on runway 06. During the approach, the pilot noted a crosswind from the right. To maintain rudder authority, the pilot executed a 'wheel landing' technique.
While the aircraft touched down on the main wheels, it did not land perfectly on the centerline. As the aircraft rolled, the tailwheel made contact with the ground. At this moment, the aircraft became uncontrollable, swerving to the right as the wind caught the raised right wing. The aircraft veered off the runway, striking a runway light. The impact with the grass and the concrete base of the light caused the main gear to dig in, resulting in a high-deceleration event that flipped the aircraft onto its back. Both the pilot and the passenger were able to exit the inverted aircraft and walk away without injury.
The investigation
The AAIU(Be) conducted a data-collection investigation, reviewing meteorological records, aircraft maintenance history, and pilot experience. The investigation focused on the directional stability of taildragger aircraft and the environmental factors at the airfield. Investigators examined the impact of the runway edge lighting infrastructure and the effectiveness of the Emergency Locator Transmitter (ELT) activation.
Findings
- The aircraft's center of gravity is located behind the main wheels, making taildragger aircraft inherently unstable on the ground.
- The loss of control occurred because the tailwheel contacted the ground while the aircraft was already deviating from the centerline.
- Once the tailwheel touched, the combination of the aircraft's natural instability and the crosswind caused an unrecoverable veer to the right.
- The concrete base of the runway edge light acted as a ramp, increasing the impact forces and contributing to the aircraft flipping over.
- A delay in contacting the pilot occurred because the owner's contact details were not updated in the international 406 MHz beacon registration database.
Safety action
- The AAIU(Be) issued a safety message advising all pilots to ensure their ELT is fully registered and updated in the COSPAS-SARSAT database.
- A safety recommendation was made to aerodrome operators to consider the placement of runway edge lights to avoid infrastructure that could act as a ramp during excursions.