Following a series of recent studies by international aviation organisations, the objectives for runway safety action have extended well beyond the issue of runway incursion. Until recently, incursion had been seen as the priority target, but data now suggests it should be only one of several areas for action.
Runway excursion has now been elevated to equal priority status with runway incursion because, in the last few years, it has become the biggest killer.
Excursion has long been the most frequent type of landing accident, according to the Flight Safety Foundation's director of technical programmes Jim Burin, but it is often not fatal.
Speaking at the FSF's 10-12 March European Aviation Safety Seminar in Bucharest, Romania, Burin pointed out that a third runway safety risk category - "runway confusion" has also now formally been recognised as a killer category because of accidents like the Singapore Airlines Boeing 747-400 collision with construction equipment at Taipei in 2000, and the Comair Bombardier CRJ100ER take-off overrun at Lexington, Kentucky in 2006.
Burin's study looks at 1,332 runway accidents between 1995 and 2007, affecting all commercial aircraft. Among these, five runway incursions killed 129 people, 31 excursions killed 680, and two runway confusion accidents killed 132.
He concludes that 35% of all jet accidents and 23% of those involving turboprops are runway excursions. Jets usually overrun the end of the runway, turboprops are more likely to veer off the side. But among all runway events, 96% are excursions. In the period under study, 80% of the fatalities associated with runway events have happened in excursions. That is why the US National Transportation Safety Board has recently changed the terminology in its safety priorities list from "runway incursions" to "runway safety".
To flesh out the figures, among the 1,332 accidents to jets and turboprops, 10 were runway incursions, 379 were excursions, and four were runway confusion. Burin points out that commercial aircraft average less than one runway incursion a year but suffer 29 excursions. But Burin explains that since risk is calculated as the probability of an event multiplied by its potential severity, incursion risk is still given a high rating.