Definition
An airborne navigation computer that converts VOR/DME signals into a selectable course referenced to a chosen waypoint, allowing the pilot to fly direct tracks between points that are not located at the VOR station itself. By offsetting the VOR/DME information to a phantom waypoint defined by a bearing and distance from the station, the CLC provides course guidance as if a VOR existed at that waypoint.
Plain English
A piece of cockpit equipment that lets a pilot create an imaginary navigation point at any chosen spot near a VOR/DME station and then fly straight to or from that point, instead of being forced to fly only to or from the station itself.
Context Anchor
Seen in FAA acronym lists and in discussions of navigation equipment, especially where older or integrated navigation systems are described.
Derivation
Course line computer is named for what it does: it computes a course line — a straight track between waypoints — using inputs from VOR and DME ground stations.
Why Pilots Care
The CLC was an early form of area navigation. It freed pilots from flying airway-to-airway via VOR stations and let them fly more direct routes, saving time and fuel. Understanding it helps explain how RNAV evolved into the GPS-based direct routing used today.
Intuition Check
Do not read “computer” here as a laptop or tablet. In aviation equipment, a computer can be a built-in electronic function that performs one specific calculation.
Example Sentence 1
Before GPS became common in general aviation, a course line computer allowed the pilot to fly direct to an airport that did not have its own VOR.
Example Sentence 2
Before electronic flight computers, many pilots carried a CLC in the cockpit to solve course corrections during cross-country flights.