Incident Overview
The incident occurred when a Cessna 172 departed Boundary Bay airport, British Columbia, on an instrument flight rules (IFR) flight to Nanaimo. The aircraft climbed to 2,000 feet above sea level (asl) in accordance with a clearance from the Vancouver departure controller. Simultaneously, a Canadian Regional de Havilland DHC-8, flight number 1360 (CDR1360), was inbound to Vancouver from Victoria at 3,000 feet asl, operating IFR under the control of the Vancouver arrival controller. The Cessna 172's departure clearance had not been coordinated with the arrival controller.
The arrival controller observed the Cessna 172 in level flight at 2,000 feet asl and assumed it was operating under visual flight rules (VFR). The arrival controller then issued a clearance to CDR1360 for a visual approach to runway 26 right, with a restriction to maintain 2,500 feet until established on final approach. CDR1360 descended out of 3,000 feet and passed ½ to ¾ nautical miles (nm) behind and about 500 feet above the Cessna 172, both in level flight. The required separation standard is 3 nm or 1,000 feet vertically. There was no risk of collision.
Operational Context
At the time, the Vancouver area control centre (ACC) terminal specialty was operating with five control positions: arrival; departure; data; VFR Terminal Area; and coordinator. The specialty was short two staff members, and the supervisor was scheduling relief breaks. The arrival position was being used for training, with a qualified on-job-instructor (OJI) responsible while overseeing a trainee.
The runway in use at Vancouver International Airport (VIA) was runway 26. Normally, when runway 26 is in use, the Boundary Bay control zone underlies the arrival controller's airspace, and Vancouver terminal specialty procedures (Article 350.3) require that IFR departures from Boundary Bay be controlled by the arrival controller. However, in this incident, the departure controller received the flight data strip for the Cessna 172 and planned to control it, contrary to the published procedure. Interviews revealed that this work practice was not uncommon, and the procedural defence was routinely circumvented by internal coordination.
Procedural Deviations
Article 300.2 of the Vancouver terminal procedures states that coordination is the sole responsibility of the coordinator. The departure controller informed the coordinator about the departing aircraft, and the coordinator provided release authority. The coordinator was required to inform the arrival controller but noticed the arrival controller was busy debriefing the trainee. Aware of a typical delay between release and takeoff, the coordinator decided to pass the information after the aircraft was airborne.
Subsequently, the supervisor initiated position changes for relief. The coordinator was moved to the departure control position. During hand-off, the outgoing coordinator omitted to brief his replacement about the un-coordinated departure from Boundary Bay. A hand-off guideline was posted but not used; the outgoing coordinator relied on a mental checklist, which did not include this information. It is generally accepted among terminal controllers and supervisors that use of the formal job aid is not essential and a mental checklist is adequate.
Coordination and Hand-off Issues
There were no visual cues or job aids at the coordinator's workstation to indicate that coordination of the Boundary Bay departure had not been completed. The incoming coordinator had to rely on the memory of the departing coordinator. This passive transfer of information reduced defences and increased error risk.
When the Cessna 172 departed, the departure controller believed its data tag (full 5-letter identifier C-GHNV) clearly indicated it was an IFR flight. The departure controller overheard the arrival controller discussing the Cessna and wake turbulence separation requirements with the trainee, leading the departure controller to conclude it was unnecessary to point out the aircraft or inform the arrival controller that it was IFR.
Air Traffic Display and Communication
In the Vancouver ACC, there is no consistent method for identifying VFR flights via data tags. IFR flights consistently receive full 5-letter identifiers. The Cessna's tag displayed the full identifier, which typically indicates IFR. However, VFR flights may be assigned abbreviated identifiers or other tag variations.
The close proximity of control positions influenced informal work practices, with communication often occurring without the ACC interphone system. The departure controller did not hear the arrival controller issue the approach clearance to CDR1360 but noticed the descent and interceded.
The coordinator's decision to delay coordination was influenced by a desire to reduce interruptions for training. The terminal specialty was short-staffed, and routine position changes occurred. The outgoing coordinator did not use the published hand-off guideline, and the incoming coordinator was unaware of the un-coordinated departure.