What happened
On December 9, 1975, a Fuji FA-200-180, registration HB-ETV, was performing landing training at the Luzern-Beromünster airfield. After completing two successful circuits, the aircraft entered its third circuit. During the approach phase on the downwind leg, witnesses observed the aircraft flying significantly lower than the prescribed minimum altitude of 900 meters. The aircraft was flying just above the treeline, placing it at risk of colliding with a 78-meter-tall high-voltage power line mast.
As the aircraft approached the mast, the pilot initiated a sudden, sharp left-hand banking maneuver of approximately 70 degrees with a nose-down pitch of 45 degrees. During this aggressive avoidance maneuver, the aircraft's airspeed dropped below the minimum required for such a bank angle, causing the left wing to stall. The aircraft subsequently struck a meadow near Neudorf, resulting in the fatal destruction of the aircraft and the death of the pilot.
The investigation
The investigation examined the flight path, the aircraft's technical condition, and the pilot's medical state. Investigators confirmed that the aircraft was airworthy and that the engine was operating at high power until the moment of impact. No mechanical failures in the flight controls or engine systems were found. The investigation also reviewed the weather conditions, which included heavy haze and a low cloud base, making the power line masts difficult to distinguish from the background.
Medical examinations revealed that the pilot had a carbon monoxide (CO) level of 20% in his blood. While this was attributed to the pilot's heavy smoking habits rather than engine exhaust leakage, investigators noted that such high levels can impair depth perception and visual perception, potentially contributing to the failure to detect the obstacle in time.
Findings
- The pilot failed to maintain the minimum required altitude on the downwind leg.
- The pilot executed a sudden, sharp avoidance maneuver to prevent a collision with a high-voltage mast.
- The aircraft dropped below minimum airspeed during this steep bank, leading to a stall.
- High levels of carbon monoxide in the pilot's blood, resulting from heavy smoking, may have impaired visual perception and contributed to the accident.