Boeing urges pilots to abort unstable approaches

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Boeing is the latest organization to address growing concern about unstable approaches, publishing an article urging pilots to perform go-arounds when they are not properly configured for landing.

The article, published in Boeing’s technical journal Aero, follows a number of recent accidents that were preceded by unstable approaches and comes as industry groups work to give pilots better go-around guidance.

Boeing’s article notes that unstable approaches are the primary cause of commercial aviation hull losses and account for one-third of all commercial aviation accidents.

It adds that industry data shows that nearly half of commercial aircraft accidents in 2011 could have been prevented by a go-around.

“The conclusion of this analysis is that flight crews need to know when to abandon an approach to landing and perform a go-around maneuver,” says Boeing’s article. “Airlines should emphasise to flight crews the importance of making the proper go-around decision.”

Boeing reiterates industry recommendations that flights be stabilised by the time they descend to an altitude of 1,000ft in instrument flight conditions and by 500ft in visual flight continues.

An approach is stable if the aircraft requires only small changes in heading and pitch and is not travelling slower than its target landing speed or more than 20kt faster than the target, says the article.

Aircraft should also have a sink rate no greater than 1,000ft/min and be properly configured, and the crew should have completed checklists.

Meanwhile, the US-based Flight Safety Foundation is working on a study about factors surrounding unstable approaches and reasons why pilots decide to abort, or continue, such approaches.

The study will be released in mid-summer and will be followed by recommendations that the group expects to publish prior to its International Air Safety Summit in November in Abu Dhabi.

Data compiled by the group shows that 3.5% to 4% of approaches are unstable, but in 97% of those cases pilots elect to land anyway.

The increased scrutiny follows a number of recent accidents linked to unstable approaches.

Those include the 6 July crash at San Francisco of Asiana flight 214, which impacted the airport’s seawall after the aircraft’s speed degraded to 103kt, or 34kt below the reference speed for landing.

Other examples include the 22 July crash landing of Southwest flight 345 at New York’s LaGuardia airport.