Accident Overview
On 8 July 2023, at approximately 05:40 UTC (07:40 local time), a Z-37A aircraft with registration OK-HJK was involved in an accident near the village of Velké Opatovice, Czech Republic. The aircraft was operated by a legal entity and was being used for biological protection of corn crops. The pilot, who held a commercial pilot license (CPL(A)) with a qualification for aerial work (WRK), had a total flight time on the Z-37A of 240 hours, including 7 hours of agricultural operations after obtaining the qualification (39 hours including training). The accident occurred during the first working flight of the day.
Flight Details
According to the pilot's testimony, he departed from Chrudim airport (LKCR) at 04:40 UTC and landed at the non-public aerodrome LKCHOR at 05:12 UTC. After receiving maps of the treated fields from the client, he took off at 05:30 UTC for the first working flight. He performed a reconnaissance of the field and then initiated a working pass in an east-west direction. After a working turn, he began a second pass in the opposite direction. At the end of the field, he executed another turn to start a third pass along the southern edge. During this pass, the aircraft contacted and severed high-voltage wires. The pilot reported that the flight altitude during treatment ranged from 5 to 15 meters depending on obstacles.
Following the wire strike, the pilot assessed that the aircraft remained controllable and decided to return to LKCHOR. He landed safely at 05:42 UTC. The pilot stated that he had previously inspected the field and noted low-voltage wires, but misjudged the height difference where the low-voltage lines connected to a higher-voltage line. He had mistakenly assumed the wire height was consistent across the entire field.
Damage and Injuries
Post-flight inspection revealed damage to the rudder, the upper right half of the wing, and the propeller. No other damage was reported. The pilot was not injured. There was no fire. The accident also resulted in damage to high-voltage power lines, but no other ground casualties or damage were reported.
Meteorological Conditions
The weather at the time was reported as CAVOK (ceiling and visibility OK), with no significant changes. The closest METAR from Brno/Tuřany airport (LKTB) indicated good visibility and clear skies.
Probable Cause
The investigation commission determined the cause of the accident to be the pilot's erroneous assessment of the situation and subsequent underestimation of the obstacles.