Eclipse DME - From the King Himself
There is a lot of confusion about the DME function on the Eclipse 500. I want to give you the facts. First and foremost there was never intended and has never been a DME receiver installed on the Eclipse 500. This is simply due to the fact the FAA made a very enlightened and informed decision several years ago that the expensive and unreliable DME system could be easily replaced by the GPS system. So when we received FAA Type Certification in September, 2006 that included operations up to 41,000 feet with "synthetic DME". The FAA approved the Distance Function that uses two GPS signals to give distance information to a fix in place of a conventional DME system. This Distance Function will accurately display to the pilot the distance between the aircraft and a navigation station tuned on the NAV receiver. This system avoids the DME slant-range error that is most prevalent at higher altitudes and gives the pilot a more accurate distance from aircraft position to the fix. Crossing directly over a nav fix at FL410 and having your distance indication show 8 miles to go to the fix is always somewhat amusing. The distance is calculated from the position of the navigation station, as retrieved from a navigation database. Therefore the currency of the database MUST be verified prior to using the Distance Function to ensure safe operations.
When we received the type certificate, the navigation database was up to date and allowed the synthetic DME Distance Function to be used. As you all know from IFR flying, the navigation database needs to be updated every 28 days, but the current version of Avidyne hardware installed in Eclipse 500s does not allow for cyclical updates.As a result the Eclipse 500 fleet has been limited to flying below FL240 due to the lack of current navigation database. The simple reason that the database could not be updated is due to the fact that Avidyne could not make the UBS interface port work correctly. Avidyne has now solved that problem and is working on new hardware to be installed that will allow us to update the navigation database. This new hardware is supposed to be approved and available to us any day now. As soon as the new hardware is approved, we will install the new hardware and navigation database and the "DME inoperative" restriction will be removed.
For those of you who simply can't stand to be without a DME receiver you can always order the International Operations Package and have a single DME receiver, in addition to an ADF receiver installed in your Eclipse 500. We have created this option for those that will be basing their aircraft in nations that have not taken the progressives steps that the FAA to start the modernization of their airtraffic control systems.
Vern Raburn President & CEO