What happened
On May 18, 2004, at approximately 11:30 SELC, an Z 37A aircraft, registration OK-NJJ, was performing aerial chemical spraying of vegetation near the village of Staré Smrkovice. The aircraft, operated by AIR SPECIAL a.s., was flying at an altitude of approximately 5 to 10 meters above the terrain as part of its 16th pass of the area.
While the pilot was completing the spraying of a specific field boundary, the aircraft's landing gear struck high-voltage overhead power lines. The impact caused the wires to break. Following the strike, the pilot performed a subsequent pass at an altitude of 20 meters to assess the situation before successfully returning to land at the takeoff area near Chomutice.
The collision resulted in minor damage to the aircraft, including a broken fender bracket and electrical discharge marks on the right landing gear strut. The severed power lines caused a local electricity outage lasting approximately 3.5 hours.
The investigation
The investigation examined the flight conditions, the pilot's actions, and the environmental factors at the site. The investigation established that the pilot was fully qualified with a valid commercial pilot license and medical certificate. The aircraft was found to be in a fully airworthy condition, and its maintenance was in compliance with manufacturer procedures. Meteorological conditions were favorable, with good visibility and no turbulence.
Investigators noted that the pilot was working with a flight plan provided by the customer, which included red markings for the location of electrical lines. However, the investigation focused on the pilot's perception of the terrain and obstacles during the final maneuvers.