What happened
On August 16, 2002, a homebuilt BD-5B/J jet, registration HB-YAU, crashed near Iragna, Switzerland. The aircraft, powered by a Microturbo turbine engine, was participating in a homebuilt aircraft gathering in Lodrino. After taking off from Locarno-Magadino earlier that day, the pilot departed Lodrino at 17:57 local time.
While the initial takeoff was captured on video by an amateur and appeared normal, the pilot did not proceed toward Magadino as intended but instead re-entered the Lodrino airfield circuit. Witnesses observed the aircraft flying at an altitude of approximately 300 to 350 meters AGL. As the aircraft flew near Iragna at a lower altitude of 100 to 150 meters, it suddenly banked sharply to the left and plummeted in a near-vertical descent, striking the ground at an angle of approximately 110 degrees. The impact resulted in one fatality and the total destruction of the aircraft by fire.
The investigation
Because the BD-5B/J was a homebuilt aircraft without standard certification, the investigation was limited to primary points of interest. Investigators examined the aircraft's maintenance history, which was found to be highly incomplete, with no recorded annual inspections or maintenance entries between 1998 and 2002.
The pilot's medical history was also scrutinized. Although the pilot had been declared fit for flight following a medical exam two days prior, he had chronic conditions, including hypertension, glaucoma, and poorly managed diabetes. While toxicology showed a blood alcohol level of 0.35 ‰, investigators noted this could have resulted from post-mortem fermentation.
Physical examination of the wreckage revealed that the turbine was functioning correctly at the time of the accident. However, investigators noted the absence of the left portion of the elevator. The remaining right side of the elevator showed a spar that was bent backward, a detail that did not align with the forward force expected from a vertical impact.
Findings
Two primary hypotheses were established to explain the loss of control, though neither could be definitively proven:
- Pilot incapacitation: The pilot's medical history of diabetes and hypertension suggested the possibility of an acute cerebrovascular or coronary event, which could have led to a loss of control or a physical blockage of the flight controls.
- Structural failure: The missing left elevator component and the backward bend of the remaining spar suggested a structural failure of the elevator during flight, potentially due to material fatigue or external forces.
No definitive conclusion could be reached because the intense fire prevented a detailed examination of the pilot's internal organs, and the missing elevator part was never recovered.