What happened
On June 22, 1970, at 08:42 GMT, a Pilatus PC-6/B1-H2 Turbo-Porter, registration HB-FCW, crashed shortly after departing from an oil drilling site in the Libyan Sahara. The aircraft was performing a medical evacuation mission to transport an injured worker to a hospital in Benghazi.
During the takeoff roll at the desert airstrip near concession HH.l/82, the aircraft entered a sharp left-hand turn at an altitude of approximately 45 meters. The aircraft rolled heavily to the left, eventually striking the ground with its left wing, flipping over, and catching fire. The impact resulted in one fatality, the pilot, and the total destruction of the aircraft.
The investigation
Following the accident, investigators from the Swiss Federal Office of Civil Aviation and Pilatus Aircraft Works AG traveled to the site in Libya. The investigation involved examining the wreckage and conducting micro-analytical studies on recovered components in Switzerland.
Witness testimony from a ground worker indicated that while he had assisted in removing various covers and locks from the left side of the aircraft, the pilot had been working on the rear and right side of the plane. Forensic analysis of the wreckage by the Zurich City Police scientific service confirmed that certain aileron locks were still in place at the time of the crash. Specifically, a securing hook from a right-wing aileron lock was found in the sand near the impact site, and another lock was discovered approximately 40 cm from the wing's damage point.
Findings
- The primary cause of the accident was that the pilot initiated takeoff without removing the aileron locks from the right wing.
- Because the engine and propeller rotated to the right, a left-turning torque (reaction moment) was generated during takeoff.
- The pilot was unable to counteract this leftward roll because the aileron controls were physically restricted by the remaining locks.
- As the aircraft banked steeply to the left, it lost airspeed and stalled, leading to the ground impact.
- The pilot's urgent focus on the medical emergency and the extreme heat (32°C) likely contributed to the oversight during pre-flight checks.