Few navigation systems have experienced the ups and downs of loran as they sought recognition. In December, a UK agency said the system is an essential back-up to GPS; the same month the FAA rejected it for the same purpose and an independent group of U.S. experts unanimously endorsed the system as a backup. To outside onlookers, the alternating acceptance/rejection/acceptance of the system must appear puzzling, a circumstance certainly not helped by the mysterious e-Loran term that nowadays creeps into discussions of the system.
What exactly is e-Loran? To most pilots, loran was a pre-GPS navaid that obtained its position from curving radio position lines transmitted from groups of stations–called “chains”–in widely separated parts of the nation. The accuracy was fairly good, but precipitation static could wipe it out, and on longer trips you either had to retune to different station combinations in the same chain or switch to another chain entirely. GPS, with its higher accuracy, all-weather performance and nationwide turn-on-and-forget-it technology, essentially ended the loran era.
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