Extended Distance and Automation Trial of Flight Management Computer Parallel Offset

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. At previous DASC conferences, three separate trials of the FMC offset have been described, in which: 1) the basic feasibility and pilot/controller acceptance were explored, 2) ATC handoffs across facility boundaries were exercised, and 3) potential airline benefits were calculated and pilot/controller phraseology was developed. In the most recent trial, a JetBlue flight from San Diego to New York Kennedy airport was offset soon after take-off, with the intent of staying on the parallel offset track for the entire transcontinental trip. The objective of the test was to uncover potential ATC automation issues, since a variety of situations would be encountered as the flight traversed various sectors and facility airspace.