History of the Flight
On 3 July 2017, a Cessna-U206G, registered F-GAMJ, took off from runway 25 of Granville–Mont Saint-Michel aerodrome at 15:20 with a pilot and four parachutists on board. After dropping the parachutists at FL100, the pilot began descending. At approximately 3,000 ft, smoke appeared from the instrument panel. The pilot made an emergency call on the aerodrome’s A/A frequency, then set the electrical equipment switches to OFF, and a few seconds later turned the battery switch to OFF. The primary instruments—airspeed indicator, altimeter, and vertical speed indicator—ceased operating, and the smoke thickened. The altitude was estimated at around 2,000 ft, and the pilot experienced breathing difficulties. On final approach at a height considered sufficient, he shut down the engine and landed on runway 07 despite thick smoke and breathing difficulties. After evacuating the aircraft, he observed fire at the instrument panel and engine cowling. The fire was extinguished using the aircraft fire extinguisher and a second one brought by a person on the ground.
Additional Information
Pilot Information
The pilot held a CPL(A) licence and had logged 386 flight hours, with 148 hours on type and 61 hours in the 30 days preceding the accident, all on type. He had been employed by Vendée Aviation since 23 March 2017 and was conducting parachute drop flights for a company based at Granville–Mont Saint-Michel aerodrome under a wet lease agreement. The pilot reported that due to breathing difficulties, he did not identify the cause of the smoke and chose not to use the on-board fire extinguisher in flight, fearing reduced visibility and breathing issues. He opened his left window and attempted to put his head outside but experienced apneas. He also opened air vents, contrary to the emergency procedure. Before landing, he activated the flap control to extend flaps and was surprised they extended despite all electrical switches being OFF.
Aircraft Information
The aircraft was equipped with a dry chemical fire extinguisher under the pilot’s seat, but no crew breathing or oxygen equipment, as per regulations for flights of less than 30 minutes between FL100 and FL130. The emergency procedure in the Vendée Aviation operations manual specified the following actions for an electrical fire in flight: Master Switch OFF, Magnetos kept ON, all other switches OFF, heating/ventilation OFF, and air vents closed. The aircraft flight manual recommended using the on-board fire extinguisher if available and, if oxygen equipment was present, to use it until smoke cleared. F-GAMJ was maintained by Hubert Aviation under a continuing airworthiness arrangement.
Damage to Aeroplane
Damage was concentrated on the left side of the cockpit, between the firewall and instrument panel, along the fuselage and stick axis, and between the instrument panel vizor and its bottom. Externally, soot appeared under the windshield and at cabin air intakes; the left side of the airframe was blackened. The engine compartment showed no damage. Internally, the windshield was opaque from extinguishing agent and heat. The instrument panel skin was deformed by heat on the left side; the vizor was burnt locally. The turn indicator was dislodged behind the panel. Soot was present between the firewall and instrument panel, and a harness of cables behind the control panel showed melted insulation.
Technical Examinations
Examination revealed that glass wool, flexible sheaths, and instruments on the instrument panel were exposed to temperatures above 300 °C, causing the smoke. The highest temperatures occurred near the alternator cable feedthrough and along the fuselage in line with the turn indicator, airspeed indicator, and cylinder head temperature indicator. The battery, alternator, contactors, and 60 A circuit breaker showed no anomalies. Several melted cables in contact with each other were found behind the control panel, likely a consequence of abnormal temperature rise. The alternator control (model DGR3, different from the originally specified DGR5) had internal components destroyed, possibly from the same heat. The alternator cable supplying the busbar was examined but no further details were provided.