What happened
On September 11, 2005, at 10:30 UTC, a SAAB-SAFIR 91D, registration OE-KSS, was taxiing at Brno Tuřany Airport (LKTB) as part of the TEAM 2000 formation flight for the CIAF 2005 airshow. The aircraft was taxiing from a designated parking area on a grass surface toward taxiway TWY A, following a lead aircraft in the formation.
As the pilot transitioned from the grass area onto the taxiway, the nose gear encountered a 35 cm deep cavity located at the interface between the grass and the concrete edge of a drainage channel. The sudden collapse of the nose gear caused the aircraft's nose to pitch forward abruptly, resulting in the propeller blades striking the concrete surface of the taxiway. The impact deformed the propeller tips and caused the engine to stop immediately. The pilot was uninjured, and no fuel leaks were detected by the airport rescue and fire service.
The investigation
The ÚZPLN investigation established that the pilot was properly qualified and held a valid medical certificate. The aircraft was also fully compliant with airworthiness and maintenance requirements. The investigation focused on the condition of the taxiing surface and the visibility of the hazard. It was noted that the pilot's forward view of the terrain directly in front of the nose wheel was obstructed during the taxi maneuver. Furthermore, the investigation found that the airport operator had designated the specific grass area for parking the formation group, and this area was considered suitable for aircraft movement.
Findings
- The primary cause of the incident was the unexpected collapse of the nose gear into a cavity formed by soil erosion at the junction of the grass surface and the concrete drainage channel.
- The cavity, measuring approximately 50 cm wide and 35 cm deep, was covered by grass and had not been detected by the airport operator during surface inspections prior to the airshow operations.
- The pilot's view of the ground immediately in front of the nose wheel was obscured during the taxiing process.
- The damage to the aircraft included the destruction of both propeller blades due to the impact and deformation of the tips by 230 mm.