What happened
On June 15, 2020, a Cirrus SR20, registration OK-BOL, attempted a takeoff from runway 26 at Frýdlant Airport. The pilot was performing a planned flight to transport three passengers to Ostrava/Mošnov.
During the takeoff roll on the unpaved, grass surface, the aircraft failed to accelerate as expected. Despite the pilot attempting to maintain a nose-up attitude to relieve pressure on the nose gear, the aircraft's acceleration ceased. The aircraft eventually struck tall grass, which became lodged between the elevator and the stabilizer. The aircraft then impacted the ground, causing the tail section to scrape the surface, and ultimately veered off the runway, coming to a stop in a field approximately 200 meters beyond the runway end. There were no injuries to the pilot or passengers, though the aircraft sustained substantial damage.
The investigation
The ÚZPLN investigation examined the pilot's pre-flight preparations, the aircraft's performance calculations, and the physical condition of the airfield. The investigation reviewed flight data, NOTAM records, and meteorological reports from the Czech Hydrometeorological Institute.
Investigators analyzed the takeoff technique, noting that the pilot used an improper method by attempting to takeoff at an angle to the runway to compensate for wind. The investigation also examined the impact of the unharvested, wet grass on the runway surface and the validity of the performance calculations performed using a non-standard mobile application rather than the official Pilot's Operating Handbook (POH).
Findings
- The pilot failed to review current NOTAMs, which contained information regarding reduced runway load-bearing capacity.
- The pilot ignored a verbal warning from the airfield operator regarding the wet runway conditions.
- Performance calculations were performed using an unofficial application, which did not account for the high rolling resistance of wet, unharvested grass.
- The pilot did not implement a standard takeoff abort procedure (such as the 70/50 rule) despite the aircraft's failure to accelerate.
- The aircraft's stall warning triggered during the roll, but the pilot did not abort the takeoff.
- The primary cause was a flawed decision-making process by the pilot and the failure to execute a takeoff abort procedure despite having sufficient information to do so.
- Environmental factors, including a variable tailwind, a saturated runway surface, and tall, unharvested grass, significantly hindered acceleration.