While on route from Galway, Ireland to Paris, France, the crew of a Beech King Air 350 (F-GVLB) became aware of the acrid smell of an electrical fire while cruising at Flight Level 330
F-GVLB coming on the approach during another flight (©Alexander Portas)
As soon a the crew became aware of the smell a "Mayday" call was made to ATC and an emergency descent was initiated to Flight level 120. The captain decided to perform the Smoke Removal Drill as per the Emergency Checklist, although no smoke was visible.
Shortly after completing the Smoke Removal Drill the Acrid smell returned, this time with visible smoke. With Cardiff Airport as the nearest suitebal airport an emergency diversion was initiated and an uneventful landing was performed. Prior to landing the smoke dissipated. The alerted emergency services were aware of the situation and inspected the aircraft. No evidence of fire or heat was apparent.
Investigation into the source of the smoke by a licensed aircraft engineer revealed the source of the smoke to be the Right Circuit Breaker Panel. Moisture was found in this panel.
The circuit breaker panel is located below the copilot's side window.
The aircraft had been parked at Galway for two days prior to the incident flight. During this time it had rained and water had seeped through the window seal and entered the Circuit Breaker panel, causing a short circuit, This circuit breaker panel contains the circuit breakers for many of the aircraft electrical systems. These include;
Engine related systems
Bus Tie systems
Avionics Bus feeder
Other smaller system
A white line on the panel "connects" systems connected to the same supply source.
The King Air 350 Electrical System (© FlightSafety)
After de necessary repairs were made the aircraft was returned to service
The King Air 350 is a stretched model of the 300 series with two extra cabin windows on each side of the forward fuselage and winglets on wingtips, in production as King Air 350i and King Air 350iER.
Specifications for a King AIr 350;
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