What happened
On June 29, 2018, a Z-37A aircraft, registration OK-AGR, was performing a low-altitude flight near Klokočovská Lhotka. The pilot, intending to honor a deceased colleague, decided to fly low over a wedding celebration held at the Klokočov chateau to "wave" to the guests.
While maneuvering at a very low altitude over a field near the chateau, the pilot initiated a left turn. During this maneuver, the aircraft struck 35 kV overhead power lines, severing three conductors. Following the collision with the wires, the aircraft impacted the ground in a flat attitude and continued sliding for approximately 35 meters before striking the gable wall of a building. The impact caused the engine to detach, the nose to disintegrate, and the fuselage to break forward of the tail section. The pilot sustained heavy injuries and was trapped in the deformed cockpit until rescuers extracted him.
The investigation
An investigation by the ÚZPLN established that the aircraft was in a valid state of airworthiness and that no mechanical or engine failures preceded the accident. Witnesses at the scene confirmed seeing the yellow aircraft flying at a very low altitude, appearing to fly just above the treetops, before the sudden change in engine sound and the subsequent impact.
The investigation examined the pilot's flight path and the meteorological conditions, noting that while the weather was generally suitable for VFR flight, significant wind gusts and turbulence were present. The investigators also reviewed the pilot's actions during the turn, noting that the pilot attempted to use full aileron to counteract a perceived wing drop or stall condition, which likely contributed to the loss of altitude.
Findings
- The pilot made a decision to descend significantly below the minimum VFR altitude requirements.
- The low-level flight path through an area with known obstacles significantly reduced the pilot's ability to detect the overhead power lines.
- The pilot's decision to descend below minimum VFR altitude and continue the maneuver at low altitude led to the inability to see and avoid the electrical infrastructure.
- The aircraft's flight path and the low altitude made a collision with the power lines highly probable during the turn.
- The pilot was likely experiencing fatigue due to having performed agricultural work for several hours prior to the accident.