What happened
On June 10, 2020, a Bristell ELSA ultralight aircraft, registration OK-WAR 18, was conducting engine-out emergency landing training at Letňany Airport (LKLT). The flight, supervised by an instructor and a student pilot, involved simulating an engine failure by cutting the fuel supply and ignition during the landing circuit.
During the fourth turn of the circuit, the instructor attempted to restart the engine by engaging the fuel pump; however, the engine failed to respond to throttle inputs. The aircraft continued on a glide toward the airfield. As the aircraft approached the runway, the instructor took control of the aircraft and applied significant flaps in an attempt to clear the airport perimeter fence. This maneuver resulted in an excessive pitch-up, causing the aircraft to lose lift and descend sharply. The aircraft subsequently made a hard landing approximately 150 meters before the threshold of runway 05L, causing the right main landing gear to break away from the wing spar and damaging the aerodynamic fairing and wing structure.
The investigation
The ÚZPLN investigation examined the instructor's pre-flight briefing, the student's performance, the aircraft's technical condition, and the meteorological environment. The investigation utilized GPS tracking data, airport camera footage, and radio communications from Letňany Radio. The committee reviewed the training syllabus (UL 3) and noted that while the aircraft was in a valid technical state, the instructor had failed to emphasize specific landing distance requirements during the briefing. The investigation also analyzed the instructor's decision-making process regarding the altitude and position of the aircraft during the simulated failure.
Findings
- The instructor failed to emphasize during both theoretical and pre-flight briefings that the landing should be planned for the first third of the runway, despite this being a requirement in the training documentation.
- The instructor provided an inappropriate task assignment regarding the aircraft's altitude and position relative to the intended landing area.
- The instructor failed to properly account for the impact of wind direction and speed on the maneuver.
- The instructor's decision-making was reactive rather than proactive, effectively trailing the aircraft's actual flight path.
- The instructor failed to adhere to the local airport procedures regarding minimum clearance heights over airport infrastructure.
- The primary cause was a chain of events beginning with inadequate flight preparation, followed by an inappropriate task assignment and delayed instructor reactions to the flight's progression.
Safety action
Following the findings, the ÚZPLN recommended that the LAA ČR revoke the flight instructor's ultralight flight instructor qualification.