When they were on final approach on ILS 23 at Geneva airport, the crew of ATR 42-320 on cargo Farnair flight FAT6932 declared an emergency situation to air traffic control (ATC) because of a fire in the cockpit.
Despite this situation the aircraft was able to land normally and vacate the runway via rapid exit taxiway Charlie, on which it was forced to stop.
The co-pilot of Farnair flight FAT6932 reported the virtually total loss of all onboard systems to the controller and that they were no longer able to taxi on the ground.
The airport safety service (SSA), already on the spot, took charge of the aircraft and asked for the engines to be shut down.
The fire on board lasted for only a few seconds and external intervention was not necessary to fight the fire.
Technical aspects of the investigation :
- On departure on missions FAT6931/6932, the DDL (deferred defect list) contained no outstanding items.
- The mass and centre of gravity values were within the permitted limits throughout the flight.
- An earth cable was fitted incorrectly. Its lower terminal was therefore in direct contact with the strand of electrical wiring, whereas there should have been a space of at least 12.5 mm (0.5 in) between these two items.
- The tubular support to which the strand was mounted was deformed; the routing of the bundle of wires modified in this way no longer permitted compliance with the minimum separations required between the structure and other cables.
- The collars used to mount the strand to the tubular structure were not tightened sufficiently.
- The damaged strand contained more electrical wires than the original design because of modifications resulting from application of service bulletins; its diameter had therefore increased.
- It was not possible to determine the precise origin of the assembly defects.
Cause of the serious incident is due to an incipient fire caused by a short-circuit following several assembly defects.