On 26 January 2006, an Avro RJ100 being operated by Swiss European Airlines on a scheduled passenger service from Hanover to Zurich had reached the parking gate at destination in normal day visibility when a flash fire occurred following the connection of ground electrical power. The commander ordered an emergency evacuation but since the air bridge was already in position at the aircraft, the cabin crew decided to carry out a rapid disembarkation and all passengers and cabin crew were off the aircraft within two minutes. A flight deck fire extinguisher was used against the apparent origin of the fire, the vicinity of the First Officer’s rudder pedals.
An Investigation was carried out by the Swiss AAIB. It was found that the flight crew saw “an explosive flame, accompanied by extensive smoke” in the area of the First Officer’s rudder pedals”. It was noted that de-icing agents for movement areas are known to contain substances which represent potential hazards in terms of both corrosion and electrical short-circuits.
The Investigation found that ”on the basis of the chemico-physical analysis it can be assumed that the short-circuit was caused by airport manoeuvring area de-icing fluid which had penetrated the (aircraft ground electrical source) plug.” It was noted that a short-circuit in similar circumstances had previously occurred on 25 November 2005 when the ground power was switched on and that the internal investigation carried out at the time had come to the conclusion that airport surface de-icing agent had penetrated into the plug and caused the short-circuit. It was also noted that similar incidents had apparently also occurred at other airports in the region
It was noted that the First Officer had not correctly followed their prescribed duties following the evacuation order and in particular did not stop the APU. This had caused uncertainty amongst the cabin crew in respect of the order to perform an emergency evacuation. The cabin crew at the front of the cabin decided to initiate rapid disembarkation using the already-positioned air bridge and the rear cabin crew “acted only partially in accordance with the procedures specified by the airline for an emergency evacuation.”
The Investigation concluded the that Probable Cause of the event was:
“that the dock-side plug had been contaminated with de-icing fluid used for airport movement areas, causing a short circuit.
Various measures taken since during the course of the investigation were noted.
- The Airport Operator suspended access to all fixed aircraft external power supplies until additional insulation measures had been taken.
- The contracted Handling Agent issued a revised Safety Instruction in respect of the connection of fixed ground power to aircraft which included requirements to preclude the external power plug coming into contact with surface de icing fluid and to exclude ground staff from a “hazard area” defined as within 3 metres of the connection point.
- Boeing and Airbus issued a joint letter in July 2006 in respect of “the negative effects of corrosion (from contact with airport surface de icing fluids) in the area of electrical systems and brakes.”
The Final Report of the Investigation was published on 16 February 2007. No Safety Recommendations were issued.