Time to Deploy

Fri, Feb 29, 2008 — David Evans


The Federal Aviation Administration (FAA) should move from the testing phase to deployment of Runway Status Lights (RWSL) systems at airports across the country, according to a report recently released by the Department of Transportation’s Inspector General (DOT/IG). The report concludes that the lighting systems – which provide red and green lights at runway intersections to guide pilots – have been tested and proved useful for reducing runway incursions (see box 1).

The test systems gained widespread support from user groups, including pilots, officials from pilot unions, air traffic control personnel and airport managers. “All agreed that the Runway Status Light system works as intended and has no known negative impact on capacity, communication or safety,” according to the report.

Officials at the National Transportation Safety Board (NTSB) have said the system is a promising technology for addressing its longstanding “Most Wanted” safety recommendation to provide direct warnings to pilots of potential runway conflicts. In addition, in 13 February 2008 testimony to the House Subcommittee on Aviation, DOT/IG Calvin Scoville pointed out the lack of alacrity:

“In May 2007, we reported on runway safety efforts at four airports that had experienced a surge in runway incursions in 2005 and 2006 – Boston, Chicago, Philadelphia, and Los Angeles. We found that airport operators at all four locations responded to the rise in runway incursions by improving airport lighting, adding better signage, and improving runway and taxiway markings….

“However, at all four locations, the actions were taken only after an increase in the number and severity of incidents at those airports.

So what’s the hold-up? Several challenges need to be addressed, the DOT/IG report says, before the system can be effectively deployed (see box 2). One would think the bugs would have been worked out by now. After all, prototype systems have been tested at Dallas-Ft. Worth International Airport (DFW) since 2003 and at San Diego International Airport since 2005. Even in prototype configuration, the system at DFW reduced runway incursions by 70%.

Given that the FAA had planned on system-wide implementation by November 2007, it does seem time to get on with deployment. As the DOT/IG report noted,  “In our opinion, setting the target date for the final investment decision 1 year after the approval of the initial investment decision … does not meet that direction.” The direction referred to was the FAA Joint Resource Council’s call for expedited deployment. (For the report, see; for IG Scoville’s complete testimony, see g

Box 1:


The system includes both runway entrance lights (not shown) and take-off hold lights (shown here). Runway entrance lights are visible to aircraft on taxiways and warn if it is unsafe to enter or cross the runway.  Take-off hold lights illuminate red to indicate an unsafe condition when an aircraft is in position to take off. The DOT/IG audit team observed take-off hold lights on runway 18L at Dallas-Ft. Worth when the runway was unsafe to depart due to an aircraft crossing the runway in the distance. Photo: DOT/IG

Box 2:

Challenges to Efficient Deployment

b RWSL depends on ASDE-X [a radar-based surveillance system known as Airport Surface Detection Equipment – Model X], and the interface between the two systems needs to be modified, as the ASDE-X version at DFW is not the same as he version being deployed nationally.

b Some of the airports where the FAA plans to deploy RWSL are undergoing or will undertake airfield improvements. It is important to coordinate RWSL in-ground infrastructure concurrently with airfield construction.

b Part of the early success of RWSL testing has been immediate input and corrective actions by the research and development (R&D) staff. As the DOT/IG report cautions, “A key factor for maintaining project momentum will be ensuring that similar ‘hands-on’ knowledge is retained during the transition from R&D to the acquisition phases of theRWSL life cycle.”                                 Source: DOT/IG, report number AV-2008-021

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