Incident Overview
On the morning of December 22, 2004, two float-equipped Cessna 185 aircraft were conducting separate herring patrol missions on the northeast side of Vancouver Island, British Columbia. The aircraft collided in flight at approximately 0948 Pacific Standard Time near Nanoose Bay. Both pilots were able to maintain control of their aircraft after the collision and landed safely without injury.
Flight Details
Aircraft C-GGBT (serial number 18504026) was on a private business flight supporting company fishing vessels near Nanoose Bay. The pilot was monitoring radio frequencies 126.7 MHz and 122.9 MHz. Aircraft C-GTNE (serial number 18501889) was on a charter flight for Fisheries and Oceans Canada (DFO), originating from Comox. The DFO crew intended to observe herring spawn and conduct gear counts, with a planned landing near a DFO boat in Nanoose Bay to pick up a second officer. The pilot of C-GTNE was monitoring frequency 123.2 MHz.
Collision
C-GTNE had completed its spawn count near the government wharf and began a left turn to land. Simultaneously, C-GGBT was exiting Nanoose Bay in level flight at about 400 feet above ground level. The two aircraft collided in flight. The pilot of C-GTNE did not see the other aircraft; the pilot of C-GGBT saw the opposing aircraft but lacked sufficient response time to avoid the collision.
Post-Collision Actions
After the collision, both pilots established radio contact and assessed each other's damage. C-GGBT returned to and landed at Vancouver, while C-GTNE flew to Campbell River and landed without further incident. No injuries were reported.
Damage
C-GGBT sustained damage to the vertical fin and rudder. C-GTNE sustained damage to the forward compartment of the left float.
Pilot Qualifications and Aircraft Condition
Both pilots were certified and qualified, and no physiological factors were found to have affected their performance. No mechanical discrepancies were identified that could have contributed to the occurrence.
Radio Frequency Usage
Both aircraft were operating under visual flight rules (VFR). The pilots were monitoring frequencies appropriate for their respective locations and intentions: C-GGBT on 126.7 MHz and 122.9 MHz, and C-GTNE on 123.2 MHz. However, they were not on a common frequency, so any radio calls made by one pilot were not heard by the other. The selection of frequencies was consistent with standard practices for the area and each flight's purpose.
See-and-Avoid Concept
Safe VFR flight relies on the see-and-avoid concept. The effectiveness of this concept depends on pilots detecting other aircraft on collision courses in time to take evasive action. Factors affecting visual detection include physiological limitations, awareness, field of view, obstructions, aircraft conspicuity, scanning techniques, and workload. In this instance, both aircraft had enhanced conspicuity features: C-GGBT had strobe lights on wing tips and rear stabilizer; C-GTNE had pulsed landing lights and strobes.
Research cited in the investigation indicates that traffic advisories improve visual acquisition. When pilots are alerted to traffic, they are more likely to see the other aircraft and at a greater range. In this case, neither pilot was alerted by radio due to the frequency mismatch.
Conclusion
Both pilots did not see the other aircraft in time to avoid the collision. The risks associated with visual flight are well documented and can be mitigated by radio position reporting on a common frequency. The Transportation Safety Board concluded its investigation and authorized the release of this report on December 22, 2004.