DOT/DOD releases its latest federal radionavigation plan

 - May 19, 2008, 6:24 AM

Other than the occasional contradiction, the recently released federal radionavigation plan (FRP) reveals few surprises. The FRP does, however, include a revised schedule
for the gradual phaseout of certain VOR, VOR/DME and ILS installations across the continental U.S., primarily following nationwide certification of WAAS. Originally planned to commence in 2008, the phaseout has now slipped to 2011.

The biennial joint DOT/DOD federal radionavigation plan has now been published in  two volumes. It sets out federal government policy regarding the provision of current radionavigation aids for civil and military aviation, marine and land users. It also provides a broad timetable for the future availability of various systems.

The specific systems addressed are GPS; WAAS and LAAS; loran-C; VOR and VOR/DME; tactical air navigation (Tacan); ILS; microwave landing system (MLS); and NDB. Uniquely military systems are not included in the FRP.

In the past, the FRP was a single document, but the most recent one has become two documents, with the second called federal radionavigation systems (FRS). The thinking was that since much of the material in the basic FRP, such as system descriptions and statements of federal navaid legislation, remained unchanged from year to year, these could go into the companion FRS volume, allowing the FRP to be more easily updated every two years.

Some Inconsistencies

However, although this new format has worked fairly well, it is also clear from the newly released documents that since they were nearing final publication last fall, some last-minute text modifications were required to accommodate the events of September 11 and subsequent government actions, coupled with the September 10 Volpe Center report on GPS vulnerability. As a result, some conflicts appear in the printed words.

For example, the section dealing with reliance on GPS includes an extract from a 1999 Johns Hopkins University study that “GPS with appropriate WAAS/LAAS configurations can satisfy navigation performance requirements as the only navigation system installed in the aircraft and the only navigation service provided by the U.S. federal government for aviation…” After September 11 and the Volpe report, one would be hard pressed to find an FAA official who would agree with such a statement. And indeed, several paragraphs later, the FRP directly refers to the Volpe report’s recommendation that backups to GPS are required.

Unfortunately, the FRP was unable to include the assessments and recommendations released in March from the various DOT operating agencies regarding proposed steps to mitigate GPS vulnerabilities, as well as the department’s subsequent action plan in that direction (see April, page 85).

Despite its minor oddities, the FRP and its companion FRS remain useful reference additions to a flight department’s library. Free copies are available on CD-ROM from the Volpe National Transportation Systems Center, Kendall Square, Cambridge, MA 02142. The documents are also available online at www.navcen.uscg.gov/pubs/frp2001.