What happened
On 25 January 2002, a near-miss occurred in the airspace above Stockholm/Arlanda airport involving two commercial aircraft. The first, a McDonnell Douglas MD-81 operating as SAS 1551, was cleared to line up on runway 01L for departure to Amsterdam. Simultaneously, a Boeing 757-200 (registration TF-FIP) was on approach to runway 26.
As the Boeing 757-200 passed the runway threshold, the crew initiated a missed approach due to unstable wind conditions and icy runway surfaces. The air traffic controller, observing the Boeing 757-200 as if it were completing its landing, issued takeoff clearance to the McDonnell Douglas MD-81. Upon realizing the arrival had aborted, the controller immediately commanded the departing aircraft to stop. However, the crew of the McDonnell Douglas MD-81 did not perceive the instruction and continued the takeoff roll. As the aircraft lifted off, the captain spotted the climbing Boeing 757-200 to the right. By reducing the climb rate, the pilot managed to pass beneath the other aircraft. Calculations later determined the minimum horizontal separation was between 75 and 100 meters, with a vertical separation of approximately 300 meters.
The investigation
The Swedish Accident Investigation Authority (SHK) examined radio communications, air traffic control procedures, and the operational use of converging runways. The investigation reviewed the tower controller's actions and the cockpit environment of the departing aircraft. Investigators also looked into the effectiveness of the terminology used during the emergency and the specific runway configuration in use at the time, which involved departures from 01L and arrivals on 26.
Findings
- The air traffic controller issued takeoff clearance to the McDonnell Douglas MD-81 at the same time the Boeing 757-200 was initiating a missed approach.
- The crew of the McDonnell Douglas MD-81 did not hear or react to the emergency stop order due to intense focus on takeoff checklists and engine monitoring.
- The use of the runway combination (01L for departures and 26 for arrivals) presented inherent operational risks.
- The terminology used in the stop command was potentially insufficient for high-stress situations.
Safety action
The investigation led to recommendations for the Civil Aviation Administration to improve methods for controllers to judge when an aircraft has safely landed, to develop more effective emergency terminology for high-stress scenarios, and to review operational procedures for using converging runway combinations.