What happened
On 23 September 2004, a leased Boeing 767-3Q8 ER, registered as EI-DBF, was being prepared for a ferry flight from Amsterdam Schiphol to Moscow Domodedovo. After being towed from a hangar for engine start-up, the flight crew requested taxi instructions from the ground controller while positioned near taxiway Golf 5.
The controller instructed the crew to taxi straight ahead to runway 22, holding short at Golf 5. During the communication, the crew's response was noted as difficult to understand and included a phrase suggesting they had already passed a certain point. Following this exchange, the aircraft crossed the eastern hold line and proceeded across runway 22. Approximately two minutes later, the crew reported they were holding short of runway 36 at Golf 5. At this time, the ground controller notified the crew that they had crossed runway 22 without the necessary clearance and instructed them to remain at their current position. There were no injuries and no other aircraft were at risk during the event.
The investigation
The investigation focused on the breakdown in communication and the failure of established safety barriers. Investigators examined radiotelephony transcripts and radar data to reconstruct the sequence of events. The investigation looked into the procedures for runway crossing clearances, which typically require transferring the aircraft to the runway controller's frequency. It was noted that the ground controller's intention to transfer the frequency was unknown, though the low volume of traffic on runway 04/22 might have led to the aircraft remaining on the ground frequency.
Additionally, the investigation reviewed the physical infrastructure at the airport, including the status of stop bars at the Golf 5 holding position. While a stop bar had been installed, it was not yet operational or documented in the aeronautical charts at the time of the incident.
Findings
Several contributing factors led to the unauthorized runway crossing:
- The failure to transfer the aircraft from the ground controller to the runway controller for crossing clearance.
- Ambiguous taxi instructions and the potential for multiple interpretations of the aircraft's position and the phrase "Golf 5."
- A failure in the flight crew's read-back function, which prevented them from correctly verifying the instruction.
- The failure of the crew to recognize that the instruction required them to hold short of the runway they were about to cross.
- The lack of active or documented stop bar lighting to serve as a visual barrier.