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Unstable approaches

Accidents involving unstable approaches continue to occur at Canadian airports.

 Update – What has been done

  • Shortly after the release of the Watchlist, the TSB Chair presented on two occasions during the Air Transport Association of Canada (ATAC) Annual Conference in Vancouver. The presentations highlighted the air and multi-modal Watchlist issues.
  • In December 2016, TSB Board Members and the Chief Operating Officer met with senior officials from NAV CANADA at the TSB Engineering Laboratory to discuss the air and multimodal Watchlist issues.

Why this matters

Every year, there are millions of successful landings on Canadian runways. Unstable approaches, however, significantly increase the risk of accidents during the landing phase of flight—accidents that can result in aircraft damage, injuries, and even fatalities.

Recent Transportation Safety Board of Canada (TSB) investigationsFootnote 1 have found that an unstable approach was causal or contributory to several serious accidents, giving rise to recommendationsFootnote 2 related to this issue.

International research indicates that among commercial operators, 3.5% to 4% of approaches are unstable.Footnote 3 Of these, 97% are continued to a landing, with only 3% resulting in a go-around, despite airlines' stable-approach policies.

Unless there is more compliance with these policies, unstable approaches will carry on being continued to landing, increasing the risk of approach-and-landing accidents.

The tools being used by some airlines to improve flight crew compliance include flight data monitoring, flight operations quality assurance programs, explicit standard operating procedures, and non-punitive go-around policies. However, major airlines need to expand the use of these tools, evaluate them to confirm that they are effective at reducing the number of unstable approaches continued to landing, and integrate them fully into their safety management systems.

In response to the TSB's Recommendation A14-01 regarding unstable approaches, Transport Canada advised airlines in Civil Aviation Safety Alert 2014-03 to monitor and reduce the incidence of landings following unstable approaches. Subsequently, Transport Canada began an inspection campaign to assess the effectiveness of the various voluntary measures taken to reduce the number of unstable approaches that continue to a landing.

Despite these recent efforts by Transport Canada, the TSB remains concerned that, without further action, risks to the public arising from unstable approaches remain.

 Action required

This issue will remain on the Watchlist until

  • major airlines track stable-approach policy compliance through their safety management systems, and take action to reduce unstable approaches that continue to landing; and
  • there is a reduction in the number of incidents of unstable approach and in the number of accidents in which approach stability was a causal or contributory factor.

 Related information

 Previous Watchlists