Incident Description
On 17 June 1998 at 2330 hours, a Cessna 310R (registration G-BWYE) was cruising at Flight Level 100 on a cargo flight from Brussels to Glasgow with only the pilot on board. A loud 'bang' was heard, followed by acrid smoke emanating from behind the radio stack in the instrument panel. The aircraft was under the control of London ATC, who informed the pilot that he was approximately 10 to 15 nautical miles from Luton Airport with a cloudbase of 3,000 feet. Concerned about potential radio failure, the pilot requested an immediate approach. A descent was cleared, and transfer to Luton was arranged. The aircraft was vectored for a Surveillance Radar Approach (SRA) in case of navigational radio failure. After descending below cloud, the pilot continued visually and completed a successful landing.
Examination and Findings
Post-landing, the pilot discovered that the circuit breaker (CB) for the radio stack lighting had tripped. With the Airport Fire Service in attendance, resetting the CB caused smoke to reappear and the CB to trip again. An engineer from the operator subsequently examined the aircraft and found heat damage behind the instrument panel in the region of the throttle quadrant. This damage appeared to be associated with a small encapsulated static inverter, adjacent wiring, and associated connections. The inverter was examined by the AAIB; externally it appeared to have suffered an internal failure, but when sectioned, no evidence of internal overheating or burning was found.
Outcome
Following replacement of the static inverter and repairs to the local wiring, the aircraft performed normally. No injuries were reported, and damage was limited to the instrument panel, smoke damage behind the control quadrant, several melted wires, and an overheated inverter.