In the December 2014 issue, I answered a question from Tim, a reader, regarding filing an IFR flight plan. DUATS flight planner computer accepted the flight plan but the FSS planner rejected it. That was disconcerting, so we dug into it. This article will explain whats happening and Ill illustrate how different flight planning tools can behave differently with some less common routing elements.
ATC offered Tim a clearance that read KAGC AGC073 HOMEE JST300 JST SEG. ATCs intent was to have Tim depart Allegheny County, PA, join the AGC VORs 073 radial and fly it to HOMEE. Then he would fly southeast on the JST VOR 300 radial to JST. Neither route is an airway and this was not a preferred route. Tim has only VOR and DME (with a VFR GPS) aboard and filed accordingly.
Good intentions notwithstanding, ATC gave Tim a flyable clearance but not one that FSS or Center would accept if you were to file it. A clearance you cant file isnt worth much, and this one fails in two respects.