Landing at wrong airfield triggered by lack of clear data
Lack of crew awareness of a military airfield close to City of Derry airport in Londonderry, Northern Ireland led an Eirjet Airbus A320 flying to the airport to land at the base last year in error. Investigators have concluded that charts did not provide clear information about Ballykelly airfield even though it is on the approach to City of Derry.
UK air navigation service provider NATS is now to update its official aeronautical information with a specific warning highlighting the risk of confusion, and instructing pilots to identify City of Derry positively before committing to land.
While 8nm (15km) from City of Derry, as the aircraft was attempting an instrument approach, the crew told air traffic control that they did not appear to be receiving accurate glide path information and would instead carry out a visual approach. Ballykelly is 5nm east of City of Derry, almost beneath the approach path, and the crew assumed Ballykelly's runway - which has the same 08/26 orientation as City of Derry's - was the only one in the area. City of Derry's instrument landing system was undergoing calibration at the time and a calibration aircraft was still in the vicinity. This reinforced the suggestion that the glide path information had been suspect.
"Throughout flying training, pilots are taught to believe their flight instruments unless they have good reason to doubt the information being presented," says the UK Air Accidents Investigation Branch in a bulletin on the 29 March 2006 incident. "Once visual with [Ballykelly], the crew of the A320 was convinced that this was their destination airfield."
It adds that the crew's concentration on landing, rather than verifying the identity of the airport, was probably intensified by the knowledge that City of Derry has a short runway with 1,817m (5,961ft) available landing distance. The useable length at Ballykelly was 1,219m. There was also pressure to complete the arrival quickly to avoid conflict with trains using a rail line close to City of Derry's runway.
Information about Ballykelly on commercial navigation charts varies, says the AAIB, and the A320's captain claimed he would not have landed there had it been clearly identified.
Source: Flight International
