Collisions between aircraft on the ground ought to be the most preventable of all potentially serious accidents, yet they happen often and the frequency is growing. A US Federal Aviation Administration-commissioned study by the Massachusetts Institute of Technology has determined that the risk of ground collision varies with the square of the increase in traffic, which would account for a large recent increase recorded in the USA.
NASA and the FAA tests of high technology solutions look promising. The Runway Incursion Prevention System (RIPS) is a smart combination of technologies which keeps the pilots informed of their own position and that of other aircraft and airside vehicles, and provides them with guidance as to their cleared route through the maze of taxiways at major airports, even providing visual cues in poor visibility. Datalinking with air traffic control keeps controllers and controlled in touch, and should leave the pilots in no doubt as to the next holding point at which their current taxi clearance terminates. Finally, visual and aural alerts warn pilots and the tower of imminent incursion.
This smart combination of technologies has huge potential, particularly for the enormous, multiple runway airports of which the USA has many. Frequent-user pilots map-reading their way around the complex networks can find it challenging, let alone foreign occasional visitors. It is easy for pilots to enter the wrong taxiway - or even an active runway - while their heads are down discussing airport charts and their clearance to the stand or take-off point. The machine-gun delivery of ground routing instructions by controllers at airports like Chicago O'Hare or Atlanta Hartsfield may be fine for United or Delta pilots for whom the place is home, but they can intimidate other pilots, making them reluctant to request confirmation. Datalink should help a great deal in that respect.
Many airports in the USA and elsewhere, however, are not as complex and incursions still happen. The contributory factors can be many. Perhaps a small part of the airport is out of sight to the tower; sometimes more than one runway is active but the pilot has not realised it and the active runways may intersect; poor visibility makes life difficult for both the pilot and the tower; poor signage or surface lighting can increase the risk that pilots will misidentify a junction.
But in the final analysis, failure to communicate clearly, to query a clearance or to ask for confirmation or even help, causes the most runway incursions, and RIPS will not be there at all the airports.
Source: Flight International
