The flight management computer (FMC) parallel offset is a procedure which allows a pilot to turn left or right of course in order to intercept a track which is parallel to the originally-cleared route of flight. The offset route is established by way of an input parameter to the FMC. "L5.0", for example, would establish a 5 NMI offset to the left of the original route. The aircraft may turn back to course later or simply continue on the offset path until receiving vectors in the terminal arrival area. The entire procedure is subject to air traffic control (ATC) approval