What happened
On the night of 19 November 1999, a near-collision occurred on the ground at Geneva airport during operations involving Category II visibility conditions. A Lauda Air Challenger (flight LDA9235) was cleared for takeoff from runway 23. Simultaneously, a Speedwings Citation 550 (flight SPW554) was taxiing toward the runway.
The pilot of the Citation 550 had previously requested to depart from the Bravo taxiway intersection. While the controller had authorized the aircraft to proceed to a different holding point, the pilot proceeded to the Bravo intersection. As the Challenger was in its takeoff roll, the controller authorized the Citation 550 to line up on runway 23. The pilot of the Citation 550 noticed the departing aircraft at rotation speed passing their position, but delayed lining up, which prevented a collision.
The investigation
The investigation examined the controller's communications, the status of airport lighting, and the impact of external factors on the tower's workload. At the time, visibility was significantly reduced by fog, with runway visual range (RVR) as low as 400 meters in certain sections. The investigation found that the controller was heavily preoccupied with a REGA helicopter flying near the airport and landing at its base.
Records showed that while the controller had authorized the Citation 550 to taxi to the Yankee intersection, the pilot's subsequent message stating they were arriving at Bravo was not explicitly acknowledged. Furthermore, the investigation identified a discrepancy in the timing of the electrical service recordings compared to the ATC audio logs. It was also noted that the stop bars at the Bravo intersection remained illuminated, yet the aircraft passed through them.
Findings
- The primary cause was the controller authorizing the Citation 550 to line up from the Bravo intersection during the takeoff phase of the Challenger LDA9235, under the mistaken belief that the Citation 550 was positioned behind the departing aircraft.
- The controller's attention was diverted by the management of a REGA helicopter and the high volume of traffic.
- The use of imprecise phraseology by the controller contributed to the misunderstanding regarding the aircraft's position.
- The pilot of the Citation 550 proceeded through illuminated stop bars at the Bravo intersection.
Safety action
Following the investigation, the following recommendations were made:
- Takeoffs from runway intersections should be prohibited during Category II/III operations.
- English phraseology should be used for all transmissions to ensure clarity for all crews.
- Control towers should be equipped with visual and acoustic alarms to detect unauthorized runway penetrations.
- Modern Surface Movement Guidance and Control Systems (SMGCS) should be installed.