What happened
On August 11, 2024, an Aerospel WT9 Dynamic (registration 04FO) was conducting a training flight near Haguenau, France. The flight, operated by Aéroclub de Haguenau, was intended to qualify a student pilot for solo operations in the aircraft type. After taking off from Haguenau aerodrome, the crew climbed to approximately 3,100 ft before beginning a gradual descent.
During this descent, the aircraft's ground speed dropped sharply to below 50 kt. The aircraft then entered a sudden descent that transitioned into a left-hand spin. Although the airframe parachute was activated by one of the occupants, the deployment occurred too late to prevent the impact. The aircraft struck a cultivated field in Eschbach with high vertical energy and a nose-down attitude, resulting in two fatalities and the destruction of the microlight.
The investigation
The BEA examined the wreckage and recovered data from the instructor's smartwatch. Observations of the wreckage indicated the aircraft hit the ground with almost zero horizontal speed. Investigators noted that the engine was delivering low or zero power at the time of impact.
While the aircraft was equipped with an airframe parachute, the investigation established that the parachute housing door had been ejected, but the canopy had not fully inflated before impact. This suggested the activation was made at an altitude too low for the system to function effectively.
Regarding the aircraft's configuration, the investigation found that 04FO was operating near its maximum weight of 525 kg with a relatively aft center of gravity. Furthermore, unlike newer models, this specific aircraft was not equipped with stall strips, which are designed to mitigate roll movements during a stall.
Findings
- The aircraft likely entered a roll and subsequent spin during a low-speed flight or stall exercise.
- The absence of stall strips on the aircraft likely contributed to the development of the spin by failing to reduce the risk of a roll during the stall.
- The airframe parachute was activated too late in the sequence of events to prevent the fatal collision.
- The high wing loading and laminar airfoil profile of this high-performance microlight can result in sudden stall characteristics that differ from traditional aircraft.