What happened
On August 31, 2019, a chartered Comco Ikarus C 42 B ultralight aircraft departed from Mengen airfield for a sightseeing flight over the Lake Constance region. The flight, which included the pilot and a passenger, proceeded toward Konstanz under favorable weather conditions with good visibility and light winds.
At approximately 12:29, the airfield controller heard a female voice transmitting a distress call over the radio. Shortly thereafter, a male voice responded to the controller, indicating the aircraft was briefly away from the frequency. Radar data from the Bundeswehr tracked the aircraft's path, noting a change in direction toward the north at 12:29. The aircraft disappeared from radar tracking between 12:30 and 12:31, and the final radar signal was recorded at 12:34 near Tiefenbach, showing the aircraft in a shallow descent at approximately 80 knots.
The aircraft struck a group of trees at an altitude of about 8 meters before sliding into a cornfield. The impact caused significant damage to the airframe, including the destruction of the cockpit and the engine penetrating the cabin area. The pilot survived the crash with serious injuries, including multiple fractures, but the passenger was fatally injured at the scene.
The investigation
The BFU investigation focused on the sequence of events leading to the loss of control and the functionality of the aircraft's safety systems. Investigators examined radar data, radio communications, and the wreckage. The pilot stated that he experienced a loss of consciousness during the flight and only regained awareness after the impact. Medical examinations of the pilot following the accident revealed no specific underlying conditions or seizure disorders that could explain the sudden loss of consciousness.
The investigation also reviewed the aircraft's maintenance records, which showed the Comco Ikarus C 42 B was properly registered and maintained. The engine was determined to have been running at the time of the accident based on the condition of the propeller blades.
Findings
- The primary cause of the accident was the pilot's loss of consciousness, which resulted in a total loss of aircraft control during the cruise phase.
- The aircraft's integrated emergency parachute system was not deployed. While the pilot's medical cause for unconsciousness remained undetermined, the investigation noted that the passenger's failure to activate the system prevented a potential mitigation of the crash consequences.
- There was no evidence of technical failure or mechanical malfunction contributing to the accident.
- The investigation highlighted the importance of passenger briefings, noting that if the passenger had been instructed on how to operate the rescue system, they might have been able to deploy it during the period when the pilot was incapacitated.