What happened
On 16 September 2000, a sequence of events at Manchester International Airport led to a high-risk situation involving two aircraft on Runway 24R. An Airbus A320 was slow to vacate the runway following its arrival, prompting the air traffic controller to instruct the crew to expedite their exit. Simultaneously, a BAC One Eleven 530FX, registration G-AYOP, was lined up and prepared for departure to Bergamo, Italy.
An inbound Boeing 747-412(Megatop), registration 9V-SPF, was on final approach from Amsterdam. The controller, observing that the A320 had not yet cleared the runway, cleared the G-AYOP for takeoff. The commander of the 9V-SPF was aware of the departing traffic and commenced the takeoff roll. As the 9V-SPF approached the threshold, the controller noted that the G-AYOP appeared to be accelerating slowly while the inbound heavy aircraft was approaching rapidly.
Despite the tightening separation, the controller did not issue a go-around instruction or intervene until the 9V-SPF pilot initiated a go-around at approximately 50 feet above the ground. The 9V-SPF crew requested instructions as they could no longer see the departing traffic, eventually being vectored for a new approach and landing safely. The crew of the G-A-YOP only learned of the near-miss upon their return to Manchester.
The investigation
The AAIB investigation examined radar data, including Surface Movement Radar (SMR) and Node Radar, alongside radio communications. The investigation established that the 9V-SPF crossed the runway threshold while the G-AYOP was approximately 850 metres ahead. As the 9V-SPF passed the touchdown zone, the separation distance was approximately 860 metres, which later decreased to 480 metres as the aircraft continued down the runway.
Investigators reviewed the 'Land After Departure' procedure and the 'Best Practice' guidelines issued by Manchester ATC. It was noted that the controller experienced a distortion in the perception of time, a common phenomenon in high-stress, time-critical situations. The investigation also looked into the controller's failure to provide positive instructions or intervene when the separation minima were being compromised.
Findings
- The controller adhered to an initial plan despite several indicators that the plan was becoming unworkable, including the slow vacating of the runway by the preceding A320 and the slow acceleration of the G-AYOP.
- The controller failed to intervene or issue a missed approach instruction despite the increasing risk to separation.
- The controller's subsequent actions were characterized by a lack of positive control, failing to provide necessary information to the pilots of either aircraft.
- The incident was effectively resolved only by the decision of the 9V-SPF pilot to execute a go-around.