Victor route using an unusable sector of a VOR

Question

V155 is an airway that terminates at the BROOKE VORTAC on the 214 radial. The chart supplement says all of its radials are unusable (radials 001 thru 360). How could this be a valid route since no radials are usable to be able to navigate to this VORTAC after the changeover point?

Answer 1

When a victor airway is established, FAA flight test pilots verify the VOR can provide adequate / acceptable navigation along that route through (1) the halfway point to the next VOR or (2) changeover point. Since V155 uses BRV it has undoubtedly been flight tested to within acceptable tolerances. If the VOR is unusable after flight testing, a NOTAM will be issued for the VOR and most likely a FDC NOTAM issued for the airway.

The chart supplements lists navigational issues for the VOR within it's service volume as detailed in the AIM (1-1-8)

b. A NAVAID will have service volume restrictions if it does not conform to signal strength and course quality standards throughout the published SSV. Service volume restrictions are first published in Notices to Air Missions (NOTAMs) and then with the alphabetical listing of the NAVAIDs in the Chart Supplement. Service volume restrictions do not generally apply to published instrument procedures or routes unless published in NOTAMs for the affected instrument procedure or route.

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Looking at the low enroute chart for Brooke VOR.

• V155 SW bound has a change over point 10 NM past the VOR on a 53 NM leg.
• V286 NW bound uses the VOR for 20 NM before a change in heading precipitates the use on a different VOR
• V286 SE bound has a change over point 22NM past the VOR while the other VOR is used for 66NM.
• It is also interesting that OJAAY intersection is defined by the CSN VOR 39NM away instead of the Brooke VOR at 10NM away.