Latest Runway Innovations Help Pilots Avoid Ground Collisions

Air Safety Week,  Feb 20, 2006  

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The bottom line, though, is that the screens have to be usable through the entire takeoff sequence, Patterson emphasizes. This would start at the point just before takeoff, when pilots position the craft "on the numbers," then continuing all the way through the takeoff roll to the point where pilots decide whether to lift off or abort the takeoff.

Patterson emphasizes that the screens will only be practical at airports like Dallas that have enough land, and not at many eastern airports.

So, while Patterson and his colleagues continue fine-tuning their screens to make takeoffs safer, across the country at Long Beach Airport (LGB), airport officials in partnership with the FAA are preparing a months-long, real-world demonstration of the Final Approach Runway Occupancy Signal (FAROS). This system will warn pilots on an approach that there's something on the runway.

When and if FAROS becomes generally available, airports wishing to replicate the system would only need to buy some software and install some inductive loop sensors just beneath the surfaces of their runways. The glide slope indicator lights, also known as the precision approach path indicator (PAPI) lights, normally used to help pilots correctly line up their approach, would flash when an aircraft or vehicle is detected on the runway.

Long Beach already had the inductive loop sensors installed for a previous test, so all it needed to test FAROS was the software, Airport Operations Superintendant Fred Pena tells Air Safety Week. Testing is set to begin as early as March.

Inductive loop sensors have already been in use for years by local highway departments to detect the presence of automobiles in the turn lane of an intersection, for example, to activate the turn signal in the next traffic-light cycle. Embedded beneath the roadway are coils of wire that set up an electromagnetic field. Small pieces of iron, like a small iron rod, or very large pieces of iron, like automobiles and aircraft, greatly increase the inductance of the electromagnetic field. The level of inductance can then be read and used to trigger another part of the system, like warning lights.

Long Beach Airport will have three inductive loop sensors embedded under Runway 30, in areas that are being called the FAROS activation zones. "Zone 1" is under the standard full-length departure position at the end of the runway, "zone 2" is at the common departure position where the runway intersects with one of the taxiways, while the third zone is farther up at an intersection with another taxiway.

It was the FAA's Joint Safety Implementation Team that first proposed devising such a method for reducing runway incursions, and the Air Safety Foundation, which is part of that team, suggested making use of the PAPI lights, FAA says. In 2001, the FAA successfully completed a FAROS "proof-of-concept" testing phase, to see if the system would work as planned.