What happened
On July 1, 2008, at Geneva Airport, a serious air prox incident occurred involving two commercial aircraft. An Air France Airbus A321, registration F-GTAE, was on final approach for runway 23 when the pilot encountered a windshear alert at approximately 300 feet above the ground. The crew experienced a sudden loss of airspeed and a significant sink rate, prompting an immediate go-around maneuver.
Simultably, an Air Portugal Airbus A320, registration CS-TNG, had been cleared for takeoff on the same runway. As the Airbus A321 executed its missed approach, it was positioned only 0.5 NM from the runway threshold. To manage the conflict, the aerodrome controller instructed the Airbus A321 to climb to 7,000 feet while simultaneously ordering the departing Airbus A320 to cap its climb at 5,000 feet. Radar tracking later confirmed that the two aircraft reached a minimum vertical separation of only 300 ft and a horizontal separation of 1.3 NM.
The investigation
The investigation examined the sequence of events, the meteorological conditions, and the air traffic control (ATC) procedures in place. Investigators analyzed radar tracks and communication recordings to determine the exact proximity of the aircraft. The investigation also reviewed the use of reduced runway separation minima, which allows for closer spacing between aircraft under specific visual and operational conditions.
Regarding the weather, while no official windshear warnings had been issued by MeteoSwiss, investigators noted that the summer meteorological pattern could have produced isolated wind fluctuations near the approach path. The investigation also looked into the controller's decision-making process, specifically the decision not to provide essential local traffic information to the crew of F-GTAE, as the controller believed the preceding aircraft was visually identifiable.
Findings
- The primary cause of the incident was the insufficient separation between the aircraft performing the go-around and the aircraft in the takeoff phase.
- A windshear alert triggered the sudden go-around by the Airbus A321 very close to the runway threshold.
- The controller's emergency maneuvers, while intended to restore separation, resulted in a significant reduction in vertical distance between the two flights.
- The use of reduced runway separation minima contributed to the complexity of the situation, as the following aircraft already possessed high initial airspeed.