8/15/19 3/15/07 12/31/20 AIM  7110.65R CHG 2 AIM TBL 1 − 1 − 1 VOR/DME/TACAN Standard Service Volumes SSV Designator Altitude and Range Boundaries T (Terminal) From 1,000 feet ATH up to and including 12,000 feet ATH at radial distances out to 25 NM. L (Low Altitude) From 1,000 feet ATH up to and including 18,000 feet ATH at radial distances out to 40 NM. H (High Altitude) From 1,000 feet ATH up to and including 14,500 feet ATH at radial distances out to 40 NM. From 14,500 ATH up to and including 60,000 feet at radial dis- tances out to 100 NM. From 18,000 feet ATH up to and including 45,000 feet ATH at radial distances out to 130 NM. VL (VOR Low) From 1,000 feet ATH up to but not including 5,000 feet ATH at radial distances out to 40 NM. From 5,000 feet ATH up to but not including 18,000 feet ATH at radial distances out to 70 NM. VH (VOR High) From 1,000 feet ATH up to but not including 5,000 feet ATH at radial distances out to 40 NM. From 5,000 feet ATH up to but not including 14,500 feet ATH at radial distances out to 70 NM. From 14,500 ATH up to and including 60,000 feet at radial distances out to 100 NM. From 18,000 feet ATH up to and includ- ing 45,000 feet ATH at radial distances out to 130 NM. DL (DME Low) For altitudes up to 12,900 feet ATH at a radial distance corresponding to the LOS to the NAVAID. From 12,900 feet ATH up to but not including 18,000 feet ATH at radial distances out to 130 NM DH (DME High) For altitudes up to 12,900 feet ATH at a radial distance corresponding to the LOS to the NAVAID. From 12,900 ATH up to and including 60,000 feet at ra- dial distances out to 100 NM. From 12,900 feet ATH up to and including 45,000 feet ATH at radial distances out to 130 NM. d. Nondirectional Radio Beacon (NDB) SSVs. NDBs are classified according to their intended use. The ranges of NDB service volumes are shown in TBL 1 − 1 − 2. The distance (radius) is the same at all altitudes for each class. TBL 1 − 1 − 2 NDB Service Volumes Class Distance (Radius) (NM) Compass Locator 15 MH 25 H 50* HH 75 *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 Chart Supplement U.S. 1 − 1 − 9. Instrument Landing System (ILS) a. General 1. The ILS is designed to provide an approach path for exact alignment and descent of an aircraft on final approach to a runway. 2. The basic components of an ILS are the localizer, glide slope, and Outer Marker (OM) and, when installed for use with Category II or Category III instrument approach procedures, an Inner Marker (IM). 1 − 1 − 10 Navigation Aids