What happened
On 15 March 2011, a serious airprox incident occurred at Zurich Airport involving two Airbus A320-214 aircraft, registrations HB-IJH and HB-IJW, both operated by Swiss International Airlines. The incident unfolded during simultaneous operations on intersecting runways.
While the aircraft with callsign SWR 1326 was performing its takeoff roll on runway 16, the aircraft with callsign SWR 202W was executing a takeoff roll on runway 28. During the sequence, the crew of SWR 202W initiated an aborted takeoff. As the aircraft was braking, SWR 1326 continued its roll and lifted off, passing directly in front of the decelerating aircraft. This maneuver created a high-risk situation of close proximity between the two airliners.
The investigation
The Swiss Transportation Safety Investigation Board (SUST) examined the technical and operational aspects of the event, including flight data recorder (FDR) analysis from both aircraft. The investigation reviewed the air traffic control (ATC) communications, the functionality of the Runway Incursion Collision Warning System (RIMCAS), and the coordination procedures used for runway crossings at Zurich. Investigators also analyzed the workload and workstation setup of the air traffic control officer in the Aerodrome Control (ADC) position, as well as the impact of recent survey flights on navigation equipment accuracy.
Findings
- The incident was driven by the unpredictable nature of an aborted takeoff, which altered the expected traffic flow and runway occupancy.
- The air traffic control officer's management of the situation was influenced by the complexity of simultaneous runway operations and the specific challenges of the ADC workstation.
- There were identified safety deficits regarding the handling of RIMCAS alerts and the potential for false alerts within the system.
- The investigation noted that the simultaneous use of intersecting runways for departures increases the operational complexity and risk of runway incursions.