One highly knowledgeable and respected instrument instructor categorically stated that Garmin GTN navigators cannot fly DME arcs. He used the GTN simulator to prove his claim since the KMTN VOR or TACAN RWY 15 approach (Martin State Airport in Maryland) isn’t in the database. I confirmed with Garmin that he was partially correct; the approach is not in the database. The reason it is not in the database is a bit convoluted. But his conclusion was not correct. The GTN Pilot’s Guide states, “The unit supports approaches containing DME arcs.”
Usually, I’m leery of absolutes like “never” and “always.” As in mathematics, it only takes one exception to prove the opposite. Also, we must be careful not to use inductive reasoning to reach broader conclusions from scant data. I have flown several approaches with DME arcs in the GTN databases. But what’s up with Martin State?
