What happened
On a morning in early May, a West Coast Air de Havilland DHC-2, Mk 1 Beaver (registration C-GHMI) departed from the Fraser River, south of Vancouver International Airport, on a visual flight rules flight plan. The aircraft was cleared to turn right toward the Vancouver VOR after reaching 1000 feet.
Simultaneously, an Air Canada Jazz de Havilland DHC-8-100 (registration C-FDND) was cleared for takeoff from Runway 08R at Vancouver International Airport. Following a standard instrument departure, the crew initiated a right turn at 500 feet. As the aircraft climbed, the crew significantly reduced their rate of climb, dropping from 1200 feet per minute to 600 feet per minute. This maneuver brought the two aircraft into close vertical proximity, with only 400 feet of separation between them. The pilot of the C-FDND eventually spotted the C-GHMI on the left side and performed evasive maneuvers to avoid a collision.
The investigation
The investigation examined the departure procedures and air traffic control coordination during the event. It was noted that a change in wake turbulence minima-related procedures had taken effect the previous day, which caused controllers to depart aircraft from the runway threshold rather than an intersection. This change allowed the C-FDND to begin its departure turn much earlier than usual.
Investigators also looked into the actions of three different controllers: the tower south (TS), traffic advisory (TA), and departure south (DS) controllers. The investigation found that the TS controller did not issue traffic information because they did not anticipate a conflict, relying on outdated assumptions regarding departure paths. Furthermore, while the TA controller identified the C-GHMI on radar, they were preoccupied with other traffic and failed to notice the C-FDND converging from behind.
Findings
- The TS controller cleared the C-FDND for takeoff without accounting for the new departure profile, which failed to prevent the air proximity.
- A lack of coordination between the TS, TA, and DS controllers meant that the required air traffic services for the Class C airspace were not effectively provided.
- The TA controller's attention was diverted by other traffic, preventing the detection of the converging aircraft.
- The crew of the C-FDND reduced their rate of climb based on a common expectation of being allowed to remain at 2000 feet, which inadvertently extended the duration of the conflict.