Occurrence
At 0947 Atlantic standard time, a Provincial Airlines De Havilland DHC-6-300 Twin Otter (registration C-FWLG, serial number 731), operating as Speedair 961 (SPR961), and an Air Labrador De Havilland DHC-6-300 Twin Otter (registration C-FGON, serial number 369), operating as flight 205 (LAL205), collided in mid-air while maneuvering for final approach to Runway 30 at the Natuashish Airport, Newfoundland and Labrador. Neither flight crew was aware of the other aircraft. After the collision, the Provincial Airlines flight crew realized a collision had occurred; the Air Labrador flight crew did not. The right aileron of the Provincial Airlines aircraft sustained substantial damage, and the left horizontal stabilizer of the Air Labrador aircraft sustained minor damage. Both aircraft landed safely without further incident. There were no reported injuries. Both aircraft were operating under visual flight rules at an uncontrolled airport served by an aerodrome traffic frequency (ATF).
Causes and Contributing Factors
- Neither aircraft was aware of the other’s presence.
- Engaged in non-essential communications and having not heard any other aircraft at the Natuashish Airport, the attention of both flight crews was focused on landing and not actively scanning to ensure collision avoidance.
- Neither flight crew followed the standard left-hand traffic circuit, which placed LAL205 in a position that would have made it difficult for the crew to see or be seen by the crew of SPR961.
Risk Factors
- Arriving sooner than expected, LAL205 did not communicate its position and intentions on the ATF until established on final, increasing collision risk.
- The lack of explicit guidance and regulation in the Aeronautical Information Manual (AIM) and the Canadian Aviation Regulations (CARs) regarding radio communication and circuit-joining procedures at uncontrolled airports increased collision risk.
- Neither company had formal policies, procedures, or training for VFR radio communication and circuit-joining at uncontrolled airports.
- Safety culture at both companies did not actively promote sound airmanship and flight discipline during VFR operations.
- Audio selector panels on both aircraft were partially obscured from pilots’ direct line of sight, increasing risk of incorrect radio selection.
Other Observations
- Flight operations along the Labrador coast require frequent radio changes between en route and ATF frequencies, similar to areas where ATF corridors have been established.
- Neither company had documented procedures for preserving cockpit voice recorder (CVR) data after an occurrence; critical CVR data from one aircraft was lost.
- Previous incidents were not fully investigated by the companies, missing opportunities to learn safety lessons.
- Traffic alert and collision avoidance systems (TCAS) reduce the probability of mid-air collisions but were not required or installed on these aircraft.
- It is unclear whether SPR961 was monitoring or broadcasting on the correct ATF.
Safety Actions
Provincial Airlines issued an internal directive reinforcing look, listen, talk, and proper procedures; requested NAV CANADA and Transport Canada establish a frequency corridor (122.8 MHz) between Rigolet and Nain, Labrador; directed flight crews to report any deviations affecting flight safety.
Air Labrador issued a memo implementing: maintaining listening watch on both 126.7 MHz and 122.8 MHz; en route advisories on 126.7 MHz; broadcasting on 122.8 MHz within five nm of coastal airports treating them as mandatory frequency; amended Twin Otter SOPs to include sterile cockpit procedures during ground operations and flight below 5000 feet.