Wednesday, January 11, 2012

FAA NextGen Wants Your Comments on Retirement of Legacy Navigation

Welcome to Wired!

In the December 15, 2011 Federal Register, the FAA requested  your comments on its proposed plan to replace legacy navaids, like VORs, with NextGen’s GPS/WAAS RNAV everywhere and required navigation performance (RNP) where beneficial. The comment period ends on March 7, 2012, and you can read the proposal and comment on it here.

Briefly, the plan takes the next step toward NextGen’s “flexible point-to-point navigation enabled by geospatial positioning, navigation, and timing (PNT) infrastructure and aircraft advanced navigation systems.” We emphasized that last part. While not stated as such, it is another heads-up call to those whose fleets have not stepped up to NextGen nav systems.

Sure, in its proposal the FAA plans to retain an optimized network of DME stations and a “minimum operational network (MON)” of VORs to ensure safety  and continuous operations for high and low airways in the lower 48 states and terminal operations at the “Core 30 airports,” the major metropolitan hubs.

The plan also would maintain the existing ILS network to support safety during GPS outages, but it will not build new ones. All new Category I requirements will be satisfied with WAAS localizer performance with vertical guidance (LPV) instrument procedures. It sure sounds like the FAA will keep these legacy systems behind glass labeled “Break In Case of Emergency!”

There are, the proposal says, 967 VORs. More than 80 percent of them have surpassed their service life, and repair parts are getting increasingly harder to find. So the FAA plans to gradually retire them until it achieves MON coverage, which would “enable aircraft anywhere in the CONUS to proceed safely to a destination with a GPS-independent approach within 100 nm” if they are flying above 5,000 feet above ground level.

The FAA is also working on alternate positioning, navigation, and timing (ANPT) solution that would enable “further reduction of VORs below the MON.” The FAA would maintain the VORs that support international Atlantic, Pacific, and Caribbean arrivals, and it seems that ANPT might also allow their retirement.

Naturally, how closely the FAA can stick to its schedule depends on Congress. Several months ago it seemed as through the FAA’s long-term funding reauthorization would pass when 2012 was a few days old. But a recent Wall Street Journal article, Stalemate Over FAA Leaves Bill Unsettled, makes it clear that politicians continue to hold the the future of aviation hostage.

Until next time, stay 5x5, mission ready, and Wired!