1-1-8. Navigational Aid (NAVAID) Service Volumes
a. Most air navigation radio aids which provide positive course guidance have a designated standard service volume (SSV). The SSV defines the reception limits of unrestricted NAVAIDs which are usable for random/unpublished route navigation.
b. A NAVAID will be classified as restricted if it does not conform to flight inspection signal strength and course quality standards throughout the published SSV. However, the NAVAID should not be considered usable at altitudes below that which could be flown while operating under random route IFR conditions (14 CFR Section 91.177), even though these altitudes may lie within the designated SSV. Service volume restrictions are first published in Notices to Airmen (NOTAMs) and then with the alphabetical listing of the NAVAIDs in the A/FD.
c. Standard Service Volume limitations do not apply to published IFR routes or procedures.
d. VOR/DME/TACAN Standard Service Volumes (SSV).
1. Standard service volumes (SSVs) are graphically shown in FIG 1-1-1, FIG 1-1-2, FIG 1-1-3, FIG 1-1-4, and FIG 1-1-5. The SSV of a station is indicated by using the class designator as a prefix to the station type designation.
EXAMPLE- TVOR, LDME, and HVORTAC.
2. Within 25 NM, the bottom of the T service volume is defined by the curve in FIG 1-1-4. Within 40 NM, the bottoms of the L and H service volumes are defined by the curve in FIG 1-1-5. (See TBL 1-1-1.)
e. Nondirectional Radio Beacon (NDB)
1. NDBs are classified according to their intended use.
2. The ranges of NDB service volumes are shown in TBL 1-1-2. The distances (radius) are the same at all altitudes.
| TBL 1-1-1|
VOR/DME/TACAN Standard Service Volumes
|SSV Class Designator||Altitude and Range Boundaries|
|T (Terminal)||From 1,000 feet above ground level (AGL) up to and including 12,000 feet AGL at radial distances out to 25 NM.|
|L (Low Altitude)||From 1,000 feet AGL up to and including 18,000 feet AGL at radial distances out to 40 NM.|
|H (High Altitude)||From 1,000 feet AGL up to and including 14,500 feet AGL at radial distances out to 40 NM. From 14,500 AGL up to and including 60,000 feet at radial distances out to 100 NM. From 18,000 feet AGL up to and including 45,000 feet AGL at radial distances out to 130 NM.|
| TBL 1-1-2|
NDB Service Volumes
|Compass Locator||15 NM|
|*Service ranges of individual facilities may be less than 50 nautical miles (NM). Restrictions to service volumes are first published as a Notice to Airmen and then with the alphabetical listing of the NAVAID in the A/FD.|
|Aeronautical Information Manual (AIM) — Chapter 1|
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