What happened
On July 29, 1994, a Time Air Shorts SD360 was operating a visual flight rules (VFR) flight from Victoria to Vancouver at 1,500 feet. While following the established VFR route, the crew received a resolution advisory from the aircraft's traffic collision avoidance system (TCAS) commanding an immediate climb. Simultaneously, the crew observed a CT-133 military jet crossing their path from right to left. To increase lateral separation, the captain of the Shorts SD360 executed a right turn. There were no injuries or damage to either aircraft, and both continued to their destinations.
The pilot of the CT-133 was flying from NAS Whidbey Island to CFB Comox. After reaching 4,500 feet, the pilot began a descent to intercept a military-approved low-level route. Although the pilot spotted the Shorts SD360 at a distance of 3 nautical miles, the type and direction of the aircraft were not clear until the distance closed to 1.5 nautical miles. The pilot did not alter course at that time, believing sufficient clearance existed. Radar data later showed that as the CT-1ally crossed in front of the Shorts SD360, the vertical separation was only 200 feet, with a horizontal distance of approximately 4,000 feet.
The investigation
The investigation established that the two aircraft were on parallel northbound tracks prior to the encounter, with the CT-133 overtaking the Shorts SD360. The investigation found that the military pilot was unaware of the Transport Canada VFR routes, and the Vancouver Area Control Centre was unaware of the approved DND low-level route that intersected the civilian path. Furthermore, the military pilot was not aware of a recent aviation notice advising commercial operators to maintain communication with local towers in that area.
Discrepancies in separation standards were also identified. While the military pilot operated under a general guideline of a 1,000-foot protected airspace "bubble," the proximity of the crossing was close enough to trigger the Shorts SD360's TCAS and cause significant concern for the crew.
Findings
- The CT-133 pilot crossed the path of the Shorts SD360 at a distance that caused the civilian crew to fear for the safety of their aircraft.
- Differing separation standards between military and civilian pilots contributed to the event.
- There was a lack of coordination regarding intersecting routes, as neither the DND nor Transport Canada were aware of the other's established flight paths in that specific area.
- The military pilot was unaware of the specific VFR routes and the recent communication advisories for the region.