What happened
On September 30, 2011, a T-131.PA Jungmann, registration OK-ARP, was conducting a recreational flight near Dobříš, Czech Republic. The flight, which included a pilot and one passenger, involved several maneuvers, including turns at high bank angles, as the pilot intended to observe a local landmark.
During the flight, the aircraft began experiencing unusual oscillations, which the pilot initially mistook for propeller wash or approaching a stall. Despite increasing engine power to maximum, the aircraft's airspeed continued to decrease, even though the airspeed indicator remained at approximately 120 km/h. The pilot realized the aircraft was losing altitude and could not maintain speed, leading to the decision to perform an emergency landing in a nearby wooded area. While attempting to maneuver the aircraft to avoid obstacles, the plane struck the treetops and crashed into the forest, resulting in the total destruction of the aircraft. Both occupants survived the impact without injuries.
The investigation
The ÚZPLN investigation examined the aircraft's mechanical condition, the pilot's actions, and the flight trajectory. Technical inspections of the M 332 AK engine and the wooden propeller showed that the engine was functional and well-maintained, with all mechanical components meeting required standards. The investigation also analyzed the flight path, calculating that the aircraft's vertical descent rate was significantly higher than what would be expected under normal flight conditions. The commission also reviewed the legal status of the flight, noting that the flight was organized by an agency for a fee, which was in direct violation of the aircraft's experimental certificate of airworthiness.
Findings
- The primary cause of the accident was the aircraft entering a second flight regime, which led to a loss of control and the subsequent crash during the emergency landing attempt.
- The pilot failed to utilize appropriate flight techniques to recover the aircraft from this second flight regime.
- The aircraft was operating in violation of its experimental certificate, as the flight was conducted for commercial purposes (a paid flight) rather than for purely recreational or experimental use.
- A tailwind during the final phase of the flight negatively impacted the pilot's ability to manage the descent.
- The aircraft's structural failure and destruction were caused by the impact with trees and the ground.