Flight History
The Piper PA-30 Twin Comanche (registration F-BRSO) departed Toussus-le-Noble near Paris at 1553 hours on 13 March 1975 under an IFR flight plan to Geneva. The pilot, born 1912, held a private pilot license with instrument rating and had approximately 1517 total flight hours. The right front seat passenger was a private pilot with about 800 hours; the rear seat passenger was the pilot's wife. The aircraft was privately owned and had a valid certificate of airworthiness. Before departure, the pilot noted a fuel leak in the left wing tip tank and planned to have it repaired in Geneva.
Approach and Incident
After contacting Geneva Approach at 1708 hours, the pilot was vectored for an ILS approach to runway 23. At about 1734 hours, the controller noted the aircraft was approximately 2000 feet above the glide path and suggested a 360° turn to lose altitude. The pilot initiated a left 360° turn. During this maneuver, the passenger later reported that the pilot seemed preoccupied with landing gear problems. The pilot momentarily stopped communicating; the passenger took the microphone and transmitted the aircraft's call sign twice. The pilot then reestablished contact, stating he had experienced a small problem.
Loss of Control and Crash
After completing the turn, the aircraft rejoined the localizer at about 5.5 nautical miles from touchdown. The controller instructed a frequency change to tower. Suddenly, the aircraft deviated sharply to the right, crossing the localizer at approximately 45°. The pilot reported back to Approach that he was returning. Shortly after, the aircraft struck the surface of Lake Geneva near Versoix at about 1741 hours, 25 minutes before dusk.
Occupants and Damage
The pilot and his wife died; the passenger sustained non-fatal injuries and was rescued. The aircraft was destroyed. The passenger recalled that ice pieces had struck the windshield during the flight, but the engines operated normally. The aircraft's weight and center of gravity were within limits. The left wing tip tank had a known leak.
Investigation
The Swiss federal accident investigation commission conducted the inquiry. Radar and radio transcripts were analyzed. The passenger's statement indicated the pilot's attention was diverted by a potential landing gear issue.
Probable Cause
The accident was probably due to the pilot diverting his attention from flying the aircraft following an onboard incident that likely did not affect the aircraft's airworthiness, leading to loss of control.