Accident Details
On 26 January 2021 at 10:12 local time, a Mooney Aircraft Corporation M20J "201", registration HB-DIC, operated by Motorfluggruppe Birrfeld, was conducting a private flight under visual flight rules from Birrfeld aerodrome (LSZF) to Ecuvillens aerodrome (LSGE). The pilot, the sole occupant, was a Brazilian national born in 1977 holding a private pilot licence issued by the European Union Aviation Safety Agency.
Upon arrival at Ecuvillens, the runway was slightly contaminated with snow. During the first approach to runway 27, the final approach speed was slightly high. After touching down in the first third of the runway, the pilot decided to go around and performed a circuit. On the second approach to runway 27, two eyewitnesses observed the aircraft on final with the landing gear retracted. The aircraft landed on its belly, slid to the opposite end of the runway, and came to rest in snow a few metres past the threshold of runway 09. The pilot was not injured. The aircraft was seriously damaged, including the propeller, engine, landing gear, and lower fuselage. Minor ground damage occurred and two runway markers were torn off.
Pilot Information
The pilot had accumulated 338:11 hours total flight time, with 3:16 hours in the preceding 90 days, and 34:44 hours on type, with 0:39 hours in the preceding 90 days. His last flight in this aircraft was on 26 June 2020. The pilot stated that he extended the landing gear on the downwind leg for the second approach, but did not hear the gear warning horn when he reduced power.
Technical Findings
Post-accident examination revealed that the main landing gear rods were twisted, and the nose gear control rods were broken on both sides; the electric drive fuse had blown due to excessive load. The gear warning horn did not function due to a misadjusted switch. Drag marks on the lower fuselage, wheel fairings, nose gear door, and step indicated that the landing gear was most likely fully retracted at first ground contact. The propeller pitch control was found extended approximately 3 cm.
The aircraft flight manual includes a note about removing the main landing gear lower doors when operating on soft fields, tall grass, or when ice and snow may be present, to prevent damage or accumulation that could impede gear operation.
Analysis
The investigation considered two possibilities for the accident: 1. After landing on the snow-contaminated runway, the go-around may have affected gear operation, preventing full extension when the pilot later selected gear down on downwind. 2. The pilot may have forgotten to extend the gear on downwind, and only attempted to do so during the touchdown or slide, resulting in partial extension. Given the dry snow and short circuit time, the latter scenario is considered more likely.
Regardless, the final checks for landing—which include setting the propeller to small pitch and verifying the gear is down and locked—were not performed. The pilot was likely under unusually high stress during the second approach. No pre-existing technical defects other than the inoperative gear warning horn were found. The pilot's low level of recent training on the aircraft type and the defective gear warning horn contributed to the accident.