Latest Runway Innovations Help Pilots Avoid Ground Collisions

Air Safety Week, Feb 20, 2006

Two new runway technologies still in the testing phases will help pilots avoid collisions with other aircraft and airport vehicles during both takeoffs and arrivals.

On the arrival side, the Federal Aviation Administration (FAA) is about to begin a demonstration of the nation's first automated system for detecting aircraft and vehicles on runways and then alerting incoming pilots with flashing runway lights.

For enhanced safety during takeoffs, engineers with the FAA's William J. Hughes Technical Center are developing a distinctively low-tech response. Their solution would help avoid confusion for pilots who are just about to begin their takeoff roll, and who spot another aircraft far down the runway, but can't tell whether the other craft is actually on the runway or just on an "end-around taxiway." In such cases, the pilot has to get final clearance from air traffic control. Hughes Center technicians would simply to hide those aircraft behind large screens.

The Hughes Center, which is near Atlantic City, N.J., calls itself "the nation's premier aviation research and development, and test and evaluation facility" and "the national scientific test base for the FAA."

Reducing the number of runway incursions--consisting of collisions or near collisions between aircraft and other craft, ground vehicles, or other objects--is a top priority of both the FAA and the National Transportation Safety Board (NTSB). Of the 257 million aircraft arrivals and takeoffs from 2001 to 2004, there were 1,395 runway incursions--an average of nearly one per day during the four-year period, FAA says. The issue of runway incursions also has been on the NTSB's "most wanted" list of safety recommendations since 1990.

Furthermore, in three recent incidents from 2005 (at Boston in June, New York in July, and Las Vegas in September), the airport movement area safety system (AMASS) alerted air traffic control (ATC) without enough time to do much good, NTSB explains. AMASS simulations using data from actual incursions show that alerts may occur as little as 8 to 11 seconds before a potential collision. This type of situation cries out for a better system that provides direct information or warnings to pilots.

Meanwhile, for large airports with enough real estate to build them, end- around taxiways can be a great way to improve efficiency and enhance safety, says the Hughes Center's Jim Patterson. Instead of having a taxiway cutting across the middle of two or more parallel runways, it's built just beyond the runway's end.

Two airports that do have enough land beyond their runways and which have recently built end-around taxiways are Detroit Metropolitan Wayne County Airport (DTW) and Hartsfield-Jackson Atlanta Int'l (ATL). In Atlanta, the end-around taxiway happens to be on land that is quite a bit lower in elevation than the runway itself, so when looking down the runway, all one sees of an aircraft on the taxiway is the top of its tail, Patterson tells Air Safety Week.

But at Dallas-Fort Worth Int'l (DFW), everything is pretty flat. Looking down one of its 14,000-foot runways at the end-around taxiway beyond the runway's end, an airplane on the taxiway is fairly visible. So Dallas is set to become the first customer for the large screens that the Hughes Center is developing.

That will happen a few months after Patterson and his colleagues finish testing the screens at Atlantic City Int'l (ACY), which is adjacent to the center. Testing there is expected to end in April. Installation at DFW should begin early next fall.

The Atlantic City screens are 112-foot long, 13-foot high plastic cardboard sheets. For a permanent installation (like at Dallas), the dimensions will be similar, but the backing structure will be concrete. But for the purposes of testing at ACY, the screens have been mounted on truck trailers so they can be quickly moved around, says Patterson, who is the projector director for the screens at Hughes.

Recently, the screens were set up at the end of a 10,000-foot runway at ACY, with a speeding airport vehicle simulating an aircraft on a takeoff roll. Videotaping allowed the Hughes Center technicians to see how well the screens blocked the pilots' view of the area just off the end of the runway.

Moreover, the screens' mobility at ACY is allowing Patterson and his colleagues to experiment with different screen colors and varying types of visual patterns. So far, alternating patterns of red and white do well because at least one of those colors contrasts with 99 percent of the aircraft in use. Upcoming tests will determine if the colors should be arranged in a large "chevron" pattern (of stripes) or in large blocks as on a checkerboard, or in some other pattern. Checkerboard has an advantage because it's already mentally associated with other obstruction markings.

Size, of course, is a major design factor. The screens have to be large enough to hide a commercial jet, but not so large that they themselves became obtrusive. They also have to be visible day or night.