What happened
On May 13, 2024, a Skyleader 600 ultralight aircraft, registration OM-M267, crashed in a forest clearing approximately 1 km north of Luka nad Jihlavou. The aircraft was performing a flight from Jihlava to Trnava following a 25-hour maintenance inspection.
After departing from LKJI, the pilot climbed to 3,000 ft MSL and engaged the autopilot in LVL mode. During this phase, the pilot significantly reduced engine power to a level insufficient for maintaining level flight. As the aircraft began to lose airspeed, the pilot failed to increase power. The autopilot responded by pitching the nose down to maintain vertical speed, causing the airspeed to drop to approximately 80 kt.
In an attempt to correct the sudden pitch change, the pilot applied control inputs that accidentally disengaged the autopilot via the trim button on the control stick. This resulted in extreme trim changes and uncoordinated maneuvers. The aircraft entered a steep descent at a 76-degree angle, transitioning into an inverted position. The aircraft struck the ground at a high vertical descent rate, and a post-crash fire completely destroyed the wreckage. The pilot, a foreign national, sustained fatal injuries.
The investigation
The ÚZPLN investigation examined flight data from the Garmin G3X EFIS, air traffic control records, and witness statements. The investigation focused on the pilot's actions, the aircraft's mechanical state, and the cockpit environment. Investigators found that the cockpit canopy had not been properly closed and secured after the maintenance service. This failure allowed exhaust gases to enter the cockpit, resulting in a 15% carbon monoxide saturation in the pilot's blood, which likely impaired his ability to manage the emergency.
Findings
- The pilot had a valid license and medical certificate but had limited experience with this specific aircraft type.
- Improper engagement of the autopilot combined with an inappropriate reduction in engine power led to the initial loss of airspeed.
- The pilot failed to react to the decreasing airspeed and failed to activate the fully functional ballistic parachute system.
- The improperly secured canopy allowed for the ingress of exhaust fumes, contributing to carbon monoxide poisoning and pilot impairment.
- Turbulent weather conditions at low altitude further complicated the pilot's ability to maintain control after the autopilot disengaged.
Safety action
Following the investigation, the ÚZPLN issued safety recommendation CZ-25-0009, advising the manufacturer to implement visual and acoustic signaling for high carbon monoxide levels in all newly produced Skyleader 600 aircraft and to consider retrofitting existing units.