service volume

service volume

[′sər·vəs ‚väl·yəm] (navigation) That volume in airspace surrounding a VOR, Tacan, or Vortac facility within which a signal of usable strength exists and is free of interchannel and cochannel interference; the advertised service volume is defined as a simple cylinder of airspace, usually smaller than theoretical maximum, and is used in planning areas of air operations.