Runway incursions at Canadian airports decreased in 2012 compared with 2011, according to a report by NAV Canada, the country’s air traffic services (ATS) provider.1,2 The decrease included incursions attributed both to pilot deviations3 and ATS deviations,4 the report says. There were no “extreme risk” incursions in 2012.
The report also indicates that runway excursions, which are less frequent than incursions but are statistically responsible for more fatalities, were reduced year-over-year throughout the study period 2010–2012.
ATS deviations were reduced from 65 in 2011 to 40 in 2012, a 38 percent drop (Figure 1). Pilot deviations declined by 3 percent, from 212 to 205. Pedestrian or vehicle deviations5 showed almost no change from year to year.
Overall, the 2012 numbers were higher than those for 2010. ATS deviations were 90 percent more frequent than in 2010, although fewer than in 2011 — when the increase from 2010 more than tripled. The decrease in pilot deviations from 2010 to 2012 was 12 percent; from 2011 to 2012, 3 percent. Pedestrian or vehicle deviations were nearly unchanged from 2011 to 2012, but up 34 percent from 2010.
Not all incursions are created equal. NAV Canada has four risk categories, ranging from A to D.
In Category A, “extreme risk,” participants narrowly avoid a collision by taking instantaneous action — for example, rejecting a takeoff or initiating a go-around while above the runway threshold. There were no Category A incidents in 2012, compared with three the previous year and one two years earlier.
Similarly, the number of Category B incursions, “high risk,” was lower in 2012 than in either of the preceding two years (Figure 2). “High risk” is characterized as having “a significant potential for collision.” For example, action must be taken to remove an aircraft or vehicle from a runway because of traffic taking off or landing.
Category C, “some risk,” describes incursions in which “there is ample time and distance to avoid a collision.” The number of Category C incursions, 160, represented a 17 percent increase from the 137 in 2011. Incursions in Category D, “little or no risk,” were 20 percent fewer in 2012 than in the previous year, and about the same as in 2010.
The report categorizes numbers of incursions associated with pilot deviations according to operational type. Airline pilot deviations remained nearly constant over the three-year study period: 78 in 2010, 76 in 2011 and 78 in 2012. There was a wider variation in civil aviation, and an improving trend: 177 in 2010, 167 in 2011 and 141 in 2012.6 In civil aviation, then, there was a 20 percent reduction in pilot-related incursions over three years.
In the absence of data, it might be assumed that more incursions would occur in winter because weather would often reduce visibility. The report shows no such effect. Over the 2010–2012 study period, the fewest incursions were in January, February and March (65, 68 and 70, respectively). The most deviations occurred in June and July (123 and 124, respectively). The report does not speculate about the reason for this counter-intuitive finding, but a varying number of flights in different seasons may have contributed to the effect.
There was a reasonably close monthly correlation in 2010 and 2012 in the numbers of incursions. 2011 was the odd year out. In February, for example, there were 33 incursions in 2011, 16 in 2010 and 19 in 2012. In May, the equivalent numbers were 30, 16 and 31; in August, 29, 50 and 29.
The rate of incursions per 100,000 movements — landings, takeoffs and touch-and-go practices — rose during the study period when quarterly variations were mathematically smoothed (Figure 3).
Annual numbers of runway excursions7 declined during the study period (Figure 4). Landing excursions were reduced from 78 to 49, a 37 percent drop. Takeoff excursions were down from 10 to 6, and “undetermined” excursions — for which it was not possible to determine from reports which phase they occurred in — fell from 10 to 2. In total, the number of excursions from 2010 to 2012 decreased from 98 to 57, or 42 percent.
In each year, landing excursions outnumbered takeoff excursions by a considerable margin.The majority of excursions — including both takeoff and landing excursions — were classified as “loss of directional control” in each of the study period’s three years, but the number was reduced each year (Figure 5). The fewest overruns, both on takeoff and landing, occurred in 2011.
The number of excursions diminished each year in the Edmonton, Toronto and Montreal flight information regions.8
- NAV Canada. Quarterly Runway Safety Report.
- The report defines a runway incursion as “any occurrence at an aerodrome involving the incorrect presence of an aircraft, vehicle or person on the protected area of a surface designated for the landing and takeoff of an aircraft.”
- In the report, a pilot deviation is defined as “an action of a pilot that results in noncompliance with an ATC [air traffic control] instruction/clearance or a violation of a Canadian Aviation Regulation.”
- The report defines an ATS deviation as “a situation which occurs when air traffic services are being provided and when a preliminary investigation indicates that safety may have been jeopardized, less than minimum separation may have existed, or both.”
- A pedestrian or vehicle deviation is defined in the report as “a situation that occurs when a vehicle operator, a non-pilot operator of an aircraft or a pedestrian proceeds without authorization onto the protected area of a surface designated for landing or takeoff. This classification includes security breaches but excludes animals.”
- The report does not define the distinction between civil and airline operations.
- The report defines a runway excursion as occurring “when an aircraft fails to confine its takeoff or landing to the designated runway. This may occur during the takeoff roll if the aircraft leaves the runway other than by becoming fully airborne or if an attempted landing is not completed within the confines of the intended runway.”
- A flight information region (FIR) is an airspace of defined dimensions extending upward from the surface of the earth, within which a flight information service and an alerting service are provided. The Canadian Domestic Airspace is divided into the Vancouver, Edmonton, Winnipeg, Toronto, Montreal, Moncton and Gander domestic FIRs. The regions are shown visually in the Designated Airspace Handbook published by NAV Canada, p. 193. (Link was revised in January 2017.)