What happened
On 31 October 2019, an Aerospool Dynamic WT9 was performing a series of landings at the Aerodrome of Saint-Ghislain (EBSG). Following two successful circuits, the pilot attempted a third touch-and-go maneuver. During the reconfiguration phase between landing and takeoff, the pilot inadvertently moved the landing gear selector instead of the flaps switch.
Although the pilot attempted to immediately reposition the lever to the extended position, the gear had already begun to retract. Because the aircraft was traveling at an indicated airspeed between 80 and 90 km/h, the nose wheel strut collapsed. This caused the nose of the aircraft to drop, resulting in the propeller striking the runway and the engine cowling scraping the surface until the aircraft came to a halt. Both occupants of the non-commercial flight escaped without any injuries.
The investigation
The investigation focused on the mechanical and human factors involved in the accidental retraction. The aircraft, a foreign-registered ultralert, is equipped with a retractable tricycle landing gear system. This system includes a gear-blocking mechanism designed to prevent retraction when the airspeed is below 43 knots (80 km/h) by utilizing pressure from the pitot tube and static ports. If an error occurs, the system is designed to signal the mistake via three flashing green lights.
Physical damage to the aircraft included a bent propeller blade, scratches to the nose wheel strut, the exhaust pipe, and the engine cowling, as well as a broken landing light. The investigation examined the cockpit layout, noting that the landing gear switch is positioned directly below the flaps switch on the center console.
Findings
- The primary cause of the incident was the pilot's incorrect action of selecting the landing gear lever instead of the flaps lever.
- A contributing factor was the physical design of the landing gear selector, which is located in close proximity to the flaps switch.
- While the aircraft's safety system was designed to block retraction below 80 km/h, the incident occurred at a speed where the mechanism was not effectively preventing the error.