Discontinuation of VOR Service and Associated Airways
June 16, 2011 1 Comment
The other day, I was looking into an obscure issue related to instrument approach procedures, and my research led me to the Government / Industry Aeronautical Charting Forum.
The minutes of the April 27-28, 2011 meeting (PDF) include an interesting item about the future of VOR-based navigation, which I reproduce below:
Rev 4 April 7, 2011
AERONAUTICAL CHARTING FORUM
Instrument Procedures Group
ACF Meeting 11-01
FAA CONTROL __11-01-241______
SUBJECT: Discontinuation of VOR Service and Associated Airways
BACKGROUND/DISCUSSION: To meet needs for performance based navigation (PBN) and required navigation performance (RNP) for capacity, efficiency and safety area navigation (RNAV) is being implemented in the airspace of the United States. The FAA will transition to PBN based on area navigation RNAV everywhere and RNP where beneficial, enabled by Global Positioning System (GPS) as the primary means and DME/DME/IRU as an initial Alternate to ensure safety and continuous operations in the high altitudes and major terminal areas if GPS becomes unavailable.
VOR service can not meet the needs for RNAV and PBN in most situations. Therefore, the FAA is beginning to discontinue VOR service from facilities in CONUS and intends to have a minimum network in place in 2020. This discontinuation of VOR service will affect approximately half of all VORs in CONUS. Remaining facilities will be used for terminal and enroute functions and reviewed for discontinuation at a later date to move to a totally RNAV airspace system.
Existing Victor Airways and Jet Routes will be replaced by T routes (low altitude) and Q routes (high altitude) and terminal and approach procedures will be RNAV based.
1. The proposed rulemaking action with associated collection and response to comments is sufficient for this discontinuation of service. No formal rulemaking action will be needed for the discontinuation of service from each VOR facility, each airway or airway segment or for each procedure. These will be handled through the informal process used for Part 71 and Part 73 or the non-rulemaking circularization for technical changes in accordance with JO 7400.2H (PDF).
2. The following questions in aeronautical charting and flight procedures should be answered:
a. Should VORs be discontinued to remove whole Jet routes /Victor airways or should individual facilities be removed that will allow the airways to continue as is, possibly with minor rerouting? If airways are to be kept as long as possible what would the impact be on airspace design/redesign and charting?
b. Should Q and T routes be designed and implemented to replace Jet routes/ Victor airways before the VORs describing those routes are discontinued? Should the Q or T route replacing the Jet or Victor be overlayed on those airways/routes and as the VOR service is discontinued the route turns into a Q or T route?
c. When VORs are discontinued such that Victor airways or Jet routes can not be maintained should aircraft not capable of RNAV operation be cleared directly from one VOR to another?
d. For discontinuing VORs supporting terminal procedures (SIDs, STARs, SIAPs) what should the priority order be? Should service be discontinued such that arrivals, departures and approaches are maintained for each direction though not on all runways, then one direction removed and eventually all removed leaving only RNAV based procedures?
As you can see, at this point there are no specifics about which VORs will be turned off and on what schedule. That information is supposed to be in the Federal Radionavigation Plan, updated every two years (the 2010 edition is here [PDF]). The FAA is clearly thinking about the issues involved and soliciting comments from the aviation community, but the agency still hasn’t released a detailed list of navaids that it plans to shut down.