What happened
A Cessna 172, registration C-GHNV, departed Boundary Bay airport on an instrument flight rules (IFR) flight bound for Nanaimo. During its climb to 2,000 feet, the aircraft entered the airspace of a Canadian Regional de Havilland DHC-8, flight CDR1360, which was inbound to Vancouver from Victoria at 3,000 feet.
The arrival controller, believing the Cessna was operating under visual flight rules (VFR), cleared the DHC-8 for a visual approach to runway 26 right with a descent restriction to 2,500 feet. This clearance resulted in the two aircraft passing within approximately 500 feet of vertical separation and less than 1 nautical mile of lateral separation. While the separation fell below the required 1,000 feet and 3 nautical miles, the aircraft passed behind one another, and there was no risk of collision.
The investigation
The investigation focused on the communication and coordination processes within the Vancouver area control centre. It was established that the departure clearance for the Cessna 172 had not been coordinated with the arrival controller. The investigation found that the terminal specialty was operating with reduced staffing, and the arrival controller was simultaneously acting as an on-job instructor for a trainee.
Investigators examined the hand-off process between controllers. During a shift change, the outgoing coordinator failed to use the formal hand-off guidelines, relying instead on a mental checklist that omitted the uncoordinated Boundary Bay departure. Furthermore, the investigation looked into the identification of VFR versus IFR flights, finding that the aircraft data tags lacked a consistent method for distinguishing flight rules, leading the arrival controller to misidentify the CESSNA 172 as a VFR flight.
Findings
- The arrival controller issued a clearance to the DHC-8 that allowed the vertical separation to drop below the required 1,000 feet.
- Incomplete coordination of the Boundary Bay departure between the departure and arrival controllers was a primary factor.
- The coordinator delayed notifying the arrival controller of the departure to avoid interrupting a training session.
- The outgoing coordinator failed to brief the incoming coordinator on the pending traffic during the position hand-off.
- There were no visual aids at the coordinator's station to signal that coordination was still required.
- Inconsistent use of aircraft data tags led the arrival controller to believe the C-GHNV was operating under VFR.
- Local work practices were being used that bypassed established terminal procedures.