AT43, vicinity Geneva Switzerland, 2006
AT43, vicinity Geneva Switzerland, 2006
On 29 March 2006 at about 1 mile from touchdown when in VMC on a night approach to destination Geneva, an ATR 42-300 being operated by Farnair on a cargo flight experienced a sudden electrical fire in the flight deck and an emergency was declared to ATC. Despite this situation the aircraft was able to land normally and vacate the runway via an RET after which it was forced to stop.
Description
On 29 March 2006 at about 1 mile from touchdown when in VMC on a night approach to destination Geneva, an ATR 42-300 being operated by Farnair on a cargo flight experienced a sudden electrical fire in the flight deck and an emergency was declared to ATC. Despite this situation the aircraft was able to land normally and vacate the runway via an RET after which it was forced to stop. A significant loss of onboard systems was reported to have occurred due to many CBs tripping. However, because of this, the fire on board had lasted for only a few seconds and external intervention was not necessary to fight the fire.
The Investigation
The Swiss BEA/BFU carried out a Serious Incident Investigation which was published on 8 April 2009. The Findings included the following:
- 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.
The cause of the occurrence was determined to be “due to an incipient fire caused by a short-circuit following several assembly defects”.
As a result of the occurrence, the aircraft manufacturer conducted an investigation among several ATR 42/72 operators to find out if other cases of incorrect assembly of the same earth cable existed. The results showed that several instances of this fault had been found. On 14 September 2006, EASA issued an AD requiring inspection of all ATR 42/72 aircraft in which the risk of a similar short-circuit resulting from this assembly defect might exist by 31 December 2006. No Safety Recommendations were therefore made in the Final Report.
Related Articles
Fire
- Fire in the Air
- Fire Triangle
- Aircraft Fire Detection Systems
- Aircraft Fire Extinguishing Systems
- Accident and Serious Incident Reports: FIRE