What happened
On October 18, 2003, at approximately 11:35 UTC, a Z-142, registration OK-ONR, crashed in a field near the village of Mokrá Lhota, Czech Republic. The flight was a planned navigation training mission intended to practice precision navigation. The pilot departed from Benešov airfield with a second crew member on board.
To ensure the aircraft reached a specific waypoint at the scheduled time, the pilot decided to reduce speed by maneuvering the aircraft at low engine power with the flaps extended to 15 degrees. While performing a sharp right-hand turn at an altitude between 100 and 150 meters, the aircraft entered a sudden descent and struck the ground. The impact was severe, causing the total destruction of the aircraft.
The investigation
An investigation conducted by the ÚZPLN, in cooperation with the Czech Police, established that the aircraft was maintained according to all applicable regulations and was in airworthy condition prior to the flight. Meteorological conditions at the time of the accident were clear with good visibility, and weather was not a contributing factor.
Medical examinations of the two crew members revealed that both died instantly due to polytrauma. Forensic analysis confirmed that neither individual was under the influence of alcohol, drugs, or medication. While no underlying pathological conditions were found, biochemical analysis suggested the pilot experienced intense physical and mental stress, likely due to the sudden realization of the developing emergency.
Findings
- The aircraft entered a spin during a high-bank maneuver while operating at minimum engine power.
- The pilot's decision to maneuver at low power with extended flaps led the aircraft into a stall/spin condition.
- The primary cause of the accident was pilot error during maneuvering maneuvers prior to reaching the waypoint.