What happened
On February 5, 1995, a Piper PA-28-161 Warrior II, registration HB-PCG, departed Cannes-Mandelieu, France, for a flight to Sion, Switzerland. The flight, which included the pilot and three passengers, had been preceded by a day of navigating changing weather conditions across Italy and France.
As the aircraft approached the Rhône Valley, it encountered a dense layer of stratus clouds and fog. At approximately 18:01 local time, the pilot contacted Sion tower to inquire about the cloud ceiling, confirming an understanding that the ceiling was at 2,000 feet. Shortly after, the pilot announced his intention to descend below the cloud layer to reach the airfield.
Witnesses observed the aircraft flying at a very low altitude, appearing to struggle within the fog. Near the village of Fey, the aircraft was seen performing sudden, sharp turns. The plane eventually struck trees on the mountainside with reduced engine power, resulting in the destruction of the aircraft and four fatalities.
The investigation
Investigators examined the wreckage and analyzed radar tracks, which showed the aircraft moving from Cuneo through Turin and Aosta before reaching the Swiss Alps. The investigation focused on the transition from visual flight conditions to instrument meteorological conditions (IMC).
Technical examinations of the engine, including the carburetor and spark plugs, revealed no mechanical failures prior to impact. However, investigators noted that the aircraft's weight at the time of the accident was 117 lbs above its maximum allowable takeoff mass. The investigation also reviewed the pilot's communications with Sion tower and analyzed witness accounts of the aircraft's erratic flight path near the mountainside.
Findings
- The primary cause of the accident was the continuation of a VFR flight into IMC conditions.
- The flight was characterized by inadequate preparation and planning.
- The pilot likely experienced spatial disorientation while flying through the base of the stratus layer, leading to the sudden turns observed by witnesses.
- The aircraft was operating in an overweight condition, exceeding the maximum authorized mass by 117 lbs.
- The timing of the flight left the pilot with very little margin to find an alternative landing site before nightfall.