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Low visibility, blowing snow factors in King Air runway excursion in Canada
26 May 2021

In its investigation report, TSB Canada identified the recurring issue of approaches continued in low visibility environments as a contributing factor a Beech King Air runway excursion. The investigation found that the flight crew believed the landing was permitted given the absence of an approach ban, and landed even though the reported ground visibility was below the minimum aerodrome operating visibility.

On 28 April 2020, a Buffalo Airways Ltd. Beechcraft King Air A100 aircraft was conducting a charter flight under instrument flight rules, from the Cambridge Bay Airport, Nunavut to Kugaaruk, Nunavut, with two flight crew members and freight on board. Immediately after touchdown at the Kugaaruk Airport, the aircraft veered to the right and departed from the runway surface. The aircraft came to rest after colliding with a snowbank on the northwest side of the runway. The crew was uninjured and egressed the aircraft via the main cabin door. There was no fire, but the aircraft sustained substantial damage.

The investigation determined that during the later stages of the approach, a crosswind from the left, and the visual effects of blowing snow contributed to the aircraft being aligned with the right side of the runway. The aircraft touched down near the right edge of the runway and, when the right landing gear impacted the deeper snow along the runway edge, the aircraft veered to the right and departed the runway surface.

Approaches to airports north of 60°N latitude are not restricted by ground visibility and, as a result, the flight crew continued the approach when the reported visibility was ¼ statute mile, which is lower than the published advisory visibility of 1¾ statute miles for this approach. The flight crew believed that the lack of an approach ban permitted a landing, and landed at Kugaaruk Airport even though the reported ground visibility was below the minimum aerodrome operating visibility of ½ statute mile.

The rules that govern instrument approaches in Canada are too complex, confusing and ineffective at preventing pilots from conducting approaches that are not allowed, or banned, because they are below the minimum weather limits, TSB stated. In 2020, the TSB issued recommendations A20-01 and A20-02 calling on Transport Canada (TC) to review and simplify operating minima for approaches and landings at Canadian aerodromes and to introduce a mechanism to stop approaches and landings that are actually banned.

In a response to both recommendations, TC stated that it would be forming and leading an industry working group to draft a Notice of Proposed Amendment to update approach ban regulations, as well as the supporting documentation and guidance. Until these recommendations are fully addressed, there remains a risk that flight crews will initiate, or continue, approaches in weather conditions that do not permit a safe landing.

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