What happened
On August 28, 2011, a Zlin Z-142, registration OK-MNH, crashed near the village of Dražov, approximately 7 km south-southwest of Karlovy Vary Airport (LKKV). The flight, operated by Letecké akrobatické centrum Karlovy Vary, began with a solo flight of approximately 90 minutes, followed by a refueling stop. The critical flight leg commenced at 13:59 UTC, departing from runway 11.
After takeoff, the aircraft performed several maneuvers in the vicinity of Horní Slavkov and Krásno. Radar data indicated the aircraft descended to altitudes as low as 70 m AGL during these maneuvers. Following the period of activity in Krásno, witnesses near Dražov reported hearing an engine bang followed by engine failure. The aircraft was observed flying at extremely low altitudes, between 30 and 40 m AGL, traveling south toward Hlinky. Witnesses noted the engine was repeatedly misfiring and cutting out. During a right-hand turn, the engine failed again, and the aircraft entered a descent, impacting the ground and catching fire. The impact and subsequent fire destroyed the aircraft, and both occupants died at the scene.
The investigation
The ÚZPLN investigation reconstructed the flight path using multi-radar records, radio communications with Karloary Tower, and witness testimonies. Investigators examined the wreckage, the M-337AK engine, and the propeller. Technical analysis of the surviving engine components showed no mechanical wear or damage that would explain the power loss. The investigation also reviewed the medical findings, noting that while both occupants showed traces of carbon monoxide, this was likely due to the post-crash fire and did not impair their flying abilities prior to the impact. The crew were both highly experienced pilots, and no evidence of impairment by alcohol or drugs was found.
Findings
- The aircraft was performing maneuvers at a very low altitude and low airspeed.
- Witnesses confirmed repeated engine misfires and power loss during the final phase of flight.
- At the time of impact, the engine was not producing sufficient power to maintain level flight.
- The position of the flaps at 14° suggests the crew may have been attempting an emergency landing due to the loss of power.
- The primary cause of the accident was the aircraft stalling during a turn due to insufficient engine power.