The FAA wants to start turning off VORs in 2007 in anticipation of a fully functioning satellite-based navigation system using GPS. Responding to the FAA's draft report on the transition to a GPS-only system, AOPA told the FAA that the transition timeline was too aggressive, that there aren't adequate back-ups in the event of a system failure, and that the satellite-based system does not currently provide enough benefits over the existing ground-based system of VORs.
"A transition from one navigation system to another takes considerable time," said AOPA Director of Advanced Technology Randy Kenagy. "There have to be substantial benefits to pilots in place before they'll accept the transition, and AOPA has yet to see those benefits emerge."
AOPA said the replacement service needs to demonstrate significantly improved capabilities over the current system, including GPS-based precision approaches to every runway at every public-use airport in the United States, and GPS transition routes through Class B and special-use airspace. The FAA's timetable is based on a presumption that the new capabilities will become available on time and as expected. AOPA is not confident that presumption is correct.
AOPA is also concerned that the FAA plans to begin decommissioning 450 VORs, slightly less than half of the 1,033 now operating, without an adequately developed back-up plan for a failure of or interference with the GPS system. The FAA is researching loran as a possible fallback system but appears to be going forward with an aggressive transition timeline even before that research is complete.
In its comments, AOPA also pointed out that until all the pieces of a satellite navigation system are in place and functioning reliably, general aviation aircraft owners are unlikely to make what may be a high-cost, high-risk investment in new avionics.
"We strongly object to any decision to decommission ground-based navaids as discussed in the transition strategy," said Kenagy. "While some parts of the document are well thought out, some parts are still clearly notional. It is AOPA's position that continued discussion needs to occur before AOPA supports further development or use of this strategy."