How FAA Hopes to Change the Airway Structure

FAA has outlined a concept for overhauling the current network of low- and high-altitude airways. The plan is part of the FAA’s initiative to move toward performance-based navigation (PBN). At present, the proposal is just that—it isn’t a formal program with full funding.

The presentation, given at the FAA’s Aeronautical Charting Forum meeting on October 28-30, is available as a PDF in my  Aviation Documents folder at OneDrive.

The guiding principles of the proposal are:

  • “Structure where structure is necessary and point-to-point where it is not.”
  • Route structure requirements will be based on factors such as traffic demand, airspace utilization, ATC task complexity, airspace access, and user operational efficiencies.
  • Ground based airways will be retained in areas of with poor radar coverage and in mountainous terrain.

Pilots of light aircraft are most concerned about low-altitude airways and routings, including the venerable victor airways and newer T-routes.

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Regarding T-routes, FAA hopes to publish low-altitude PBN ATS routes “precisely where needed to”:

  • Access rather than circumvent Class B/C airspace
  • Lower minimum altitudes in areas of high terrain to improve access and avoid icing
  • Circumvent Special Use Airspace in safe and optimal manner

The presentation includes an interesting slide that shows daily utilization of victor airways. The average for the top 81-100 low-altitude airways was just 3 operations (in FY2013).

The graphic below shows how V2, which runs east-west across the northern part of the US, was used in the last two fiscal years. Very few aircraft flew most segments of the airway.

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Note that the segment that crosses the Cascades east of Seattle (SEA-ELN) gets regular traffic. Other segments, such as MINNY-MKG across Lake Michigan, and legs near BUF, are also well-used, probably due to ATC requirements in these high-traffic areas.

The FAA notes that 80-90% of the aircraft flying the 20 most-used victor airways are already equipped to fly T-routes, which require an IFR-approved GPS.

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Given that so many aircraft are RNAV-capable, FAA notes that “Users file any combination of route segments, NAVAIDs, and  waypoints when not route restricted by ATC and automation.”

The proposal advocates retiring existing point-to-point navigation programs to give pilots more flexibility in planning and filing direct routes. FAA says it will work with users to create a network of optimally placed waypoints. When specific routes are required, the plan would expand the network of ATC IFR preferred routes, which would not necessarily follow existing airways. Point-to-point navigation would available elsewhere.

The new routes outlines in the plan would also:

  • Increase the number of parallel route options through high density airspace
  • Reduce separation between centerlines of published routes to 8 nm
  • Circumnavigate Special Activity Airspace

For example, the program noted that T-319 passes directly over KATL, giving controllers a straightforward way to route aircraft through the Atlanta Class B airspace.

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Latest Update from FAA on Plans to Decommission VORs

Two representatives from the FAA recently provided an update on the agency’s plans to decommission VORs. The presentation, given at the FAA’s Aeronautical Charting Forum meeting on October 28-30, is available as a PDF in my Aviation Documents folder at OneDrive. The presentation largely recapped information described in briefings and white papers (described here, here, and here), but it did restate several key points and provide some new information.

Highlights from the latest presentation include:

  • The VOR MON Program will implement the [minimum operational network of VORs] by decommissioning 30-50% of the VORs in the NAS by 2025 (although the current plan retains all VORs in the designated mountainous region of the U.S.—roughly the western third of the country).
  • The reduction will begin gradually over the first five years during which time the bulk of the procedural/airway/airspace work will assessed. Then the plan is to accelerate the process, with 20-25 VORs shut down each year.
  • Only FAA owned/operated VORs will be considered for shutdown.
  • DMEs and TACANs will generally be retained.
  • Many of the remaining VORs will be enhanced to supply increased service volume. VOR standard service volume (SSV) will become 77 NM radius at 5000 ft. AGL.
  • Increase support for direct navigation between VORs without airways.
  • Retain sufficient ILSs, LOCs, and VORs to support “safe-landing” at a suitable destination with a GPS-independent approach (ILS, LOC or VOR) within 100 NM of any location within CONUS.
  • Provide seamless VOR coverage at and above 5000 ft AGL.
  • More than 5,000 instrument approaches may be affected by the reduction in operational VORs.
  • Nearly 1,300 SIDs, STARs, and ODPs may be affected by the reduction in operational VORs.
  • FAA is considering how to refer to and chart DME-only facilities.
  • Graphics in the presentation include a pair of maps that show how the current airway structure will be changed when the MON is established.

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