What happened
On 9 February 2005, an Easyjet Airbus A319, registration G-EZEC, was operating a scheduled flight from Venice to London Gatwick. While cruising at flight level 360 near the RONAK waypoint, the crew was cleared by Swiss air traffic control to a new route via waypoint INTEX and then direct to Hochwald. This new route took the aircraft through military training airspace.
Simultively, three Swiss Air Force F/A-18 fighters, including callsign Black 7, were conducting aerial combat exercises. Due to a cancelled test flight, the airspace previously reserved for higher altitudes was made available for the exercise. During the mission, a military controller diverted two fighters to intercept a foreign state aircraft. The remaining fighter, Black 7, was instructed to fly under its own navigation within specific training areas.
As Black 7 performed a rapid climb, it intercepted the path of the Easyjet aircraft. The crew of G-EZEC received a TCAS resolution advisory (RA) and initiated a climb to flight level 368. The two aircraft crossed with a lateral separation of 3.6 NM and an altitude difference of only 100 feet.
The investigation
The investigation established that the military controller (GCI) had assigned Black 7 to fly within the Davos, Beverin, and Engadin training areas. While these areas have a vertical limit of FL 280, the controller had recently been granted access to the airspace above them due to the cancelled test flight. The investigation found that the pilot of Black 7 was climbing at a very high rate, reaching FL 367.
Findings
- The pilot of the F/A-18 did not realize the altitude restriction of the newly assigned airspace.
- The Ground Controlled Interceptor (GCI) did not inform the fighter pilot of the modified altitude restriction.
- The pilot of Black 7 was performing a steep climb, reaching an average rate of 9250 ft/min, which likely reduced his situational awareness regarding the converging civil traffic.