What happened
On the morning of 7 December 2007, a Lufthansa CityLine Bombardier CLRJ700, registration D-ACPE, was taxiing for departure at Gothenburg/Landvetter airport. During the taxi sequence, the crew became distracted by the lights of another aircraft that was taxiing back to the terminal following an aborted takeoff. This distraction caused the crew to pause their checklist procedures.
While the D-ACPE crew was navigating the taxiways, an approaching Blue 1 BAE AVRO 146 RJ85, registration OH-SAK, was on its final approach to runway 21. The air traffic controller, monitoring ground radar, observed that the Lufthansa aircraft had moved past its assigned holding position and had lined up on the active runway without authorization. To prevent a collision, the controller immediately ordered the OH-SAK crew to execute a go-around. The aircraft climbed away from the runway threshold, avoiding a collision with the unauthorized aircraft on the runway.
The investigation
The Swedish Accident Investigation Board (SHK) examined radio communications, flight data, and cockpit voice recordings to determine how the incursion occurred. The investigation focused on the breakdown in communication between the ground controller and the Lufthansa crew, as well as the crew's failure to switch to the instructed tower frequency. Investigators also reviewed the use of non-standard phraseology by both the pilots and the air traffic controller.
Findings
Several factors contributed to the runway incursion:
- The crew of D-ACPE failed to contact the tower on the new frequency as instructed.
- The Lufthansa crew used non-standard phraseology during radio transmissions and omitted critical words, such as "holding point," during their readback.
- The air traffic controller did not request a readback of the clearances, which would have identified the crew's incomplete acknowledgement.
- The use of the runway number in taxi clearances created a risk of misinterpretation, potentially leading the crew to believe they had permission to line up.
- Deficiencies were identified in the self-inspection and oversight systems of both the airline and air traffic control regarding the use of standard aviation language.
Safety action
The SHK recommended that the Swedish Transport Agency explore methods for taxi clearances that exclude the runway name to reduce the risk of confusion. Additionally, the agency was encouraged to support the distribution of the European Action Plan for the Prevention of Runway Incursions (EAPPRI) within the aviation community.