What happened
On September 20, 2023, a Dynali H3 Sport microlight helicopter, registration 45ARJ, departed from a private helipad in Bazoches-les-Gallerandes for a local flight. The aircraft was operated by a private individual. Shortly after takeoff, the aircraft reached a maximum altitude of approximately 300 feet before maneuvering westward. Within about a minute of departure, the aircraft descended to an altitude of no more or less than 150 feet. While flying at this low height, the aircraft struck the ground with high energy in a nose-down attitude. The collision resulted in two fatalities, involving both the pilot and the passenger, and the total destruction of the microlight.
The investigation
Investigators analyzed wreckage and data from an on-board MoTeC engine computer. The wreckage was found on a farmed plain with no obstacles, showing evidence of a high-energy, head-on impact. The investigation examined the pilot's extensive background, noting he was a highly experienced helicopter instructor with over 30,000 helicopter flight hours and 4,000 microlight hours. While the pilot's medical examiner found him physically and mentally alert, the investigation also looked into the aircraft's technical history and the pilot's flight habits.
Data from the MoTeC computer confirmed the aircraft was flying at very low altitudes during the final stages of the flight. Although the aircraft's EFIS (Electronic Flight Instrument System) was damaged and could not provide altitude data, the engine computer's ambient pressure readings indicated the aircraft was flying below 150 feet. The investigation also noted that while the pilot's experience was vast, the aircraft's altitude calculations via pressure sensors can be subject to errors due to sensor placement and flight maneuvers.
Findings
- The aircraft collided with the ground during a low-altitude flight phase.
- The pilot was operating the aircraft at a height that disregarded necessary ground safety margins.
- Witness statements suggested the pilot had a history of performing low-altitude maneuvers in helicopters, and flight data from the microlight indicated similar low-altitude flight patterns in previous sessions.
- The investigation could not determine the specific cause of the loss of control or whether the pilot or the passenger was actively maneuvering the controls at the moment of impact.
- The low altitude of the flight left virtually no margin for recovery from any accidental flight deviation.