What happened
During the night at Vancouver International Airport, a runway incursion occurred involving two aircraft on runway 2D left. Horizon Air flight QXE31 was positioned at taxiway E, awaiting departure instructions. Simultaneously, the crew of AirBC flight ABL523 was taxiing toward the same runway via taxiway D3. After the AirBC crew requested takeoff clearance, the tower controller—occupied with other high-priority tasks—did not respond to the request but instead issued a takeoff clearance to QXE31.
Because the clearance followed immediately after their request, the crew of ABL523 failed to notice the specific call sign for the other aircraft and believed the clearance was intended for them. The crew acknowledged the instruction and began an unauthorized takeoff run from the intersection of D3 and runway 26L, following the lead of the departing QXE31. Once both aircraft were airborne, the controller instructed the AirBC flight to maintain visual flight rules and follow a runway heading.
The investigation
The investigation examined the communication protocols and environmental conditions at the time of the event. The night operations were characterized by darkness and cloud cover, which reduced visibility for both the tower controller and the flight crews. The investigation also looked into the use of multiple runway intersections for departures and the effectiveness of existing radio protocols.
Findings
- The crew of ABL523 accepted and read back a takeoff clearance that was actually intended for QXE31.
- The tower controller did not identify that the AirBC crew had incorrectly accepted the clearance.
- The controller's focus on the departing aircraft and the lack of response to the AirBC request contributed to the error.
- Nighttime conditions and limited aircraft lighting hindered the controller's ability to observe the second aircraft entering the runway and prevented the AirBC crew from seeing the aircraft ahead of them during the takeoff roll.
- The use of multiple intersections for departures increases the complexity of managing aircraft positioned near the runway.