What happened
On June 5, 2000, a Schweizer Aircraft Corp. 269C helicopter was conducting a dual-control flight training session at the Schindellegi helipad in Switzerland. The crew, consisting of an instructor and a student, intended to perform an alpine introduction flight toward Ticino.
During the takeoff phase, the pilot attempted to climb toward the southeast. However, as the aircraft gained altitude, the pilot lost sight of an unmarked railway cable located approximately 30 meters ahead of a construction excavator. Fearing the aircraft was too low to safely clear the obstacle, the instructor decided to abort the takeoff and execute a 180-degree turn back toward the apron. While attempting to maneuver and stop the aircraft before reaching a transformer station, the pilot lost control of the Schweizer Aircraft Corp. 269C. The helicopter tilted sharply, causing the main rotor to strike the ground and the tail rotor to collide with an autocrane. Both occupants remained uninjured, but the aircraft sustained heavy damage.
The investigation
SUST examined the circumstances surrounding the takeoff and the environmental conditions at the Schindellegi helipad. The investigation confirmed that both pilots held valid licenses and showed no signs of medical impairment. The aircraft was properly registered and maintained, with weight and balance within prescribed limits for both hover in ground effect (HIGE) and hover out of ground effect (HOGE).
The investigators noted that construction activities at the site had introduced several fixed and mobile obstacles to the takeoff area. Specifically, they identified an unmarked railway cable positioned in the departure path. Following the accident, this cable was marked with daytime visibility indicators.
Findings
- The primary cause of the accident was the pilot's loss of control during the aborted takeoff maneuver.
- An unmarked railway cable in the departure zone acted as a contributing factor, as its lack of visibility prompted the sudden decision to interrupt the climb.
- The presence of construction equipment, including an excavator and an autocrane, created a complex obstacle environment near the takeoff path.