Airprox at Zurich-Kloten Involving Swiss and Tunisair Aircraft (TS-IOK)

Incident Overview and Context On 23 November 2002, at 11:08 UTC, an airprox occurred on the ground at Zurich-Kloten Airport involving Swiss flight SWR195Z, an Airbus A319 with registration HB-IPS, and Tunisair flight TAR485, a Boeing B737 with registration TS-IOK. The incident took place in the area of the intersection between runways 16 and 28. ## Sequence of Events During the morning, fog conditions at Zurich-Kloten required the application of low visibility procedures. Shortly before the incident, weather conditions improved, allowing the Swiss aircraft, on an ILS approach to runway 14, to see the runway from right-hand base at 5,000 ft. The aircraft then requested a swing-over to runway 16. The air traffic controller approved the swing-over, noting that a departure was rolling on runway 28. Seventeen seconds later, the Swiss aircraft received a landing clearance for runway 16. Meanwhile, Tunisair flight TAR485 had aligned on runway 28 and was ready for takeoff. At 11:07:11 UTC, the controller issued a takeoff clearance to TAR485 while the Swiss aircraft was about to touch down on runway 16. Shortly after landing, the Swiss crew became aware of the departing Tunisair aircraft and initiated a full stop. The Airbus came to a halt approximately 50 meters north of the runway 28 shoulder. The Tunisair aircraft continued its takeoff and passed low over the runway intersection. ## Contributing Factors The controller later stated that the incident occurred because he did not make a note on the TACO (tower approach coordination) display for the approved swing-over, contrary to his usual practice. Additionally, the controller had been heavily occupied with a transponder failure on a Cessna 172 (HB-CFO) that had taken off on runway 28 about 10 minutes earlier, which caused significant delays and coordination issues. ## Safety Recommendations The investigation recommended that the Federal Office of Civil Aviation (BAZL) ensure that swing-over procedures of the described type are not applied in principle. It also recommended accelerating the implementation of the Swiss Airport Movement Area Control System (SAMAX), particularly the runway incursion monitoring and conflict alert sub-system (RIMCAS).