History of the Flight
The aircraft, a Beech King Air 350 registered F-GVLB, was operating a commercial air transport flight from Galway, Ireland, to Paris Le Bourget Airport, France. While cruising at Flight Level 330, the crew became aware of the acrid smell of burning electrical insulation. A 'MAYDAY' was transmitted to Air Traffic Control and an emergency descent to Flight Level 120 was performed. Although no visible smoke was initially present in the cockpit, the commander initiated the Smoke Removal drill. Shortly thereafter, the acrid smell returned, accompanied by smoke, prompting the crew to divert to Cardiff Airport, where an uneventful emergency landing was performed. The smoke dissipated prior to landing. The airport emergency services attended but on inspecting the aircraft could find no evidence of fire.
Cause and Damage
Subsequent investigation revealed that the burning smell had been caused by electrical shorting due to moisture ingress into the right circuit breaker panel, which is located directly below the direct vision (DV) panel in the co-pilot's side window. The aircraft had been parked outside for two days at Galway, during which time it had rained, and water had seeped past the DV panel seal and run down onto the circuit breakers. The nature of damage was limited to the right side circuit breaker panel.
Occupants and Injuries
There were two crew members and eight passengers on board. No injuries to crew or passengers were reported.