What happened
On September 19, 2004, a Cessna 182R, registration HB-CJB, was conducting a private VFR flight from Perpignan, France, to Grenchen, Switzerland. During the flight, the pilot encountered deteriorating weather conditions. While communicating with Geneva flight information services, the pilot reported being inside clouds and requested a descent.
While navigating the area, the aircraft entered a descent phase. Radar tracking showed the aircraft maintained a nearly constant rate of descent until it disappeared from radar at approximately 6,000 feet. The aircraft subsequently struck the southeastern flank of the Dent de Jaman mountain, near the Montreux municipality, and was destroyed by the impact. There were four fatalities among the pilot and three passengers.
The investigation
The SUST investigation examined the flight path, meteorological conditions, and air traffic services communications. Investigators reviewed radar plots and radio transcripts, noting that the pilot had explicitly informed controllers on multiple occasions that the aircraft was operating in instrument meteorological conditions (IMC) despite the VFR flight plan. The investigation also looked into the coordination between various air traffic control sectors, including the Geneva Flight Information Center (FIC) and the DELTA control sector.
Findings
- The primary cause of the accident was a collision with terrain during a descent while the pilot continued to operate under visual flight rules despite being in instrument meteorological conditions.
- Air traffic control services failed to provide adequate assistance to the aircraft while it was in an emergency situation.
- There were significant deficiencies in teamwork and coordination between the various air traffic service units involved.
- The ICAO chart for the South Transit route contained a confusing representation that contributed to the incident.