Investigation into the accidental short-field departure by a British Airways Boeing 777-200 at St Kitts has revealed that the taxiway misidentification which led to the incident was commonplace.
The aircraft followed the wrong taxiway at Bradshaw International Airport last September and departed from an intersection which left the twin-jet with a much shorter take-off run than expected.
In a detailed inquiry report the UK Air Accidents Investigation Branch states that the supervising air traffic controller disclosed that the taxiway misidentification was "on average, a weekly occurrence" which happened mainly to foreign carriers.
The BA 777 crew's error came despite apparently clear understanding by the pilots and air traffic control that the aircraft would depart from the 'A' intersection of St Kitts' runway 07.
Instead it incorrectly lined up to take off from the 'B' intersection and, because the crew had planned an intersection departure, an air traffic control query about backtracking was dismissed without its significance being realised.
The controller monitoring the departure was a trainee. Although he noticed the taxiway error, the AAIB says he "did not consider correcting [the crew] as he [had] been told not to be forceful towards pilots". The supervising controller, who had seen smaller aircraft take off from the 'B' intersection, also pointed out to the trainee that pilots were aware of the performance capabilities of their aircraft.
Two BA employees travelling as passengers realised the crew's taxiing error, but could not act in time to prevent the departure. Despite the shorter runway distance, the 777 became airborne in about 860m (2,800ft) and the flight continued without further incident.
Bradshaw International Airport's operator has since made a few signage improvements, says the AAIB. But it adds that the airport infrastructure is still not ICAO-compliant and that NOTAMs should be issued to highlight the situation.