Jumbo nearly hit Gatwick terminal: A computer error and mistakes by a flight crew and an air traffic controller almost led to disaster. Christian Wolmar reports

A JUMBO jet with 241 passengers and crew on board narrowly missed hitting the main terminal at Gatwick airport after a series of mistakes by the flight crew and an air traffic controller, an investigation reported yesterday.

Following an equipment failure, the crew wrongly disregarded their own instrument readings because an air traffic controller had given the wrong information and the aircraft attempted to come in to land at an angle to the runway. Another air traffic controller saw the aircraft come out of cloud at about 1,000ft and thought it was heading directly towards the control tower but then it banked and aborted the landing.

The Continental Boeing 747 was making its second misdirected approach trying to land on the main runway at Gatwick at about 10.30am on 7 February last year during a period of poor visibility when, according to a report by the Department of Transport's Air Accidents Investigation Branch, 'it passed close to the south terminal building'.

The investigators suggest the jumbo was about 900ft off course, and was 100ft above the building with its wing tip about 400ft from making contact.

The aircraft, Continental 04, had abandoned its first approach after the crew realised that they were more than half a mile off course, according to the report. It was abandoned after 'a certain amount of confusion' on the flight deck. The descent was aborted about 3 miles from the runway at a height of 1,200ft.

The problem was caused by a fault in the aircraft's auto pilot which meant that it started its descent from the wrong point. When it came round for a second attempt at landing, it was again in the wrong position when it started its glidepath down towards the runway. The crew were not aware that the auto pilot's locating equipment had failed totally, and the captain said 'we had an electronic malfunction but we've got everything under control now'.

This time the Boeing started its descent 2,500ft away from the correct point and this error was compounded by an air traffic controller who relayed the wrong information about the aircraft's heading to the crew. The controller repeatedly told them the aircraft was just 'north of the centre line', the proper line of approach, when in fact it was far off course.

By the time the captain aborted the landing, because the aircraft was in the wrong position to reach the runway, it had reached 432ft above sea level, while the south terminal building is 316ft high.

The crew, unaware of how narrowly they had missed the terminal building, ignored a suggestion from the operations duty manager to divert to another airport because of the poor weather and the aircraft finally made a normal instrument landing on its third attempt. A spokesman for the Civil Aviation Authority said that in cases such as these the working practices and procedures of the air traffic controller in question would be examined. 'He may need some retraining or his validation may need to be checked,' he said. But he added that he had not heard of any sackings in circumstances such as these.

The investigators have recommended that the US Federal Aviation Administration consider whether a warning light should be fitted on all aircraft to alert pilots to similar failures in the locating equipment.

Report on the incident to Boeing 747-243, N33021 at London Gatwick Airport on 7 February 1993; Department of Transport; pounds 18.

(Photograph and map omitted)