What happened
On May 29, 1978, at approximately 11:38 local time, a homebuilt BD-5B, registration HB-YAE, crashed during an approach to runway 21 at the Lugano aerodrome. The aircraft, which had been assembled by the pilot, was performing a local flight after the pilot had transported the disassembled plane to the airfield via trailer.
During the approach, the aircraft was observed flying at an altitude of approximately 450 meters, significantly lower than the prescribed 800 meters. Witnesses noted the aircraft flying very low over the railway area. The aircraft suddenly pitched forward and struck the ground approximately 1,600 meters from the start of the runway, about 110 meters to the right of the runway centerline. The impact resulted in the death of the pilot and the total destruction of the aircraft.
The investigation
Investigators examined the aircraft's engine, which was a modified Honda Civic engine, and found that the camshaft sprocket had broken, though evidence suggests this breakage occurred upon impact. The investigation also reviewed the pilot's flight history, noting that while he was a licensed pilot, he had only 11 minutes of flight time in this specific BD-5B model.
Technical analysis of the cockpit revealed that the fuel valve was set to the left tank, the ignition was on, and the throttle was at full power. The investigation also looked into the engine's behavior, noting that the engine had a known tendency to stall when the throttle was abruptly reduced. Furthermore, the pilot had not established radio contact with the airfield manager during the flight, despite an agreement to do so if engine noise became an issue.
Findings
- The primary cause of the accident was the aircraft dropping below its minimum required airspeed while at a low altitude during the approach.
- The pilot's limited experience with the BD-5B contributed to the accident.
- The engine may have stalled during the maneuver, a known issue when reducing power on this specific powerplant.
- The unusual placement of the control lever and the aircraft's poor maneuverability and sensitivity to control oscillations were contributing factors.
- The pilot's approach path was tighter than recommended, limiting his available maneuvering space.