What happened
On May 11, 2013, a Socata TB 10 Tobago, registration D-EANH, was involved in a serious accident at the Vrchlabí airport (LKVR) in the Czech Republic. Following heavy rainfall on the preceding days, the unpaved grass runway was heavily saturated and soft.
The pilot attempted several takeoff runs. During an earlier attempt, the aircraft's wheels sank into the mud, requiring the aircraft to be towed out by a tractor. After cleaning the wheels and removing the wheel fairings, the pilot initiated a final takeoff attempt from the northwest edge of runway 11.
During this run, the aircraft failed to gain sufficient speed due to the high resistance of the wet, soft surface and taller grass outside the maintained runway strip. The aircraft traveled approximately 1,060 meters, crossing a field path and moving toward the village of Lánov. While the aircraft briefly rotated, the right wing caught on tall vegetation, causing the aircraft to tilt heavily to the right. The aircraft then struck a fence and bushes before colliding with the roof of the Tedec hotel building at a 45-degree angle. The impact caused the destruction of the aircraft, including the separation of the wings, propeller, and tail surfaces. The pilot and a passenger both sustained serious injuries.
The investigation
The ÚZPLN investigation established that the aircraft was within its maximum takeoff weight and that the engine and mechanical systems were functioning correctly prior to the impact. Investigators noted that the pilot did not establish radio contact with the AFIS dispatcher during the final takeoff roll. The investigation also examined the track of the wheels, which showed the aircraft was struggling to maintain speed on the soft terrain and was operating with the nose wheel lifted for a portion of the roll.
Findings
- The primary cause was the pilot's decision to attempt a takeoff despite knowing the runway conditions were unsuitable due to heavy saturation.
- The soft, muddy surface of the runway and the higher grass outside the runway strip significantly impeded the aircraft's ability to accelerate.
- The pilot failed to abort the takeoff run before reaching the end of the runway, despite the lack of sufficient airspeed.
- Heavy rainfall in the preceding 48 hours had rendered the grass runway highly unstable and prone to sinking.