What happened
On a morning in Labrador, two De Havilland DHC-6-300 Twin Otter aircraft were performing maneuvers for final approach to Runway 30 at Natuashish Airport. The first aircraft, a Provincial Airlines flight registered C-FWLG, was operating a passenger service. The second aircraft, an Air Labrador cargo flight registered C-FGON, was also in the vicinity. At 0947 Atlantic standard time, the two aircraft collided in mid-air. The impact caused substantial damage to the right aileron of C-FWLG and minor damage to the left horizontal stabilizer of C-FGON. Despite the collision, both crews managed to land their aircraft safely, and there were no injuries reported.
The investigation
The investigation examined several factors, including communication, airmanship, and regulatory guidance. It was determined that neither flight crew was aware of the other's presence prior to the impact. The investigation found that the Air Labrador crew had arrived earlier than expected and began their communications only while executing a steep right descending turn toward final approach, a maneuver that reduced their visibility to other aircraft.
Furthermore, the investigation looked into the regulatory environment, noting that while the Aeronautical Information Manual (AIM) provides recommendations for joining circuits, the Canadian Aviation Regulations (CARs) lacked unambiguous requirements for mandatory communications at this uncontrolled airport. The investigation also noted that neither operator had established formal training or specific procedures for VFR operations at uncontrolled airports served by an aerodrome traffic frequency (ATF). Additionally, the investigation found that safety cultures at both companies allowed for non-essential radio chatter and lacked active supervision regarding proper circuit-joining procedures.
Findings
- The primary cause of the collision was that neither aircraft was aware of the other's presence.
- Both flight crews were engaged in non-essential communications and were focused on landing rather than maintaining an active visual scan.
- Neither crew followed the standard left-hand traffic circuit, which placed the Air Labrador aircraft in a position that made it difficult to be seen or to see the Provincial Airlines aircraft.
- The Air Labrador crew did not communicate their position and intentions on the ATF until they were already established on final approach.
- A lack of explicit regulatory guidance regarding radio communication and circuit-joining procedures at uncontrolled airports increased the risk of error.
- The physical location of the audio selector panels on both aircraft made it difficult for pilots to visually confirm they were monitoring the correct frequency.