I’ve heard rumours that Garmin might be considering or even working on a new pure DME product. I wonder how much wishful thinking is in that vs a real possibility.
Many of the previously installed DME’s have been removed during panel upgrades on the basis that they are no longer needed, despite the discussions about whether certain operations are actually legal without. I believe all new IFR-equipped aircraft are now delivered without DME. Most avionics shops don’t want to touch them anymore and I’m told that the displays are becoming difficult if not impossible to source. True? And yet a used Narco 890 demands $1’300 used with warranty and complete used KN63/KDI572 packages are being quoted in the $3’000-$5’000 range.
I wonder what the market would be for a new DME product with modern technology production parts and methods.
A lot of countries (like Switzerland) are phasing out both ILS/LOC and VOR approaches, which means that associated DME’s are also no longer needed. It would be interesting to see the data on installed operational DME stations over the past 10 years. With the questions being raised about backup alternatives to GPS, and the US intent to use the MON network including DMEs, there still doesn’t seem to be serious consideration in Europe….. any forums at AERO where pointed questions on this could be asked?
chflyer wrote:
It would be interesting to see the data on installed operational DME stations over the past 10 years. With the questions being raised about backup alternatives to GPS, and the US intent to use the MON network including DMEs, there still doesn’t seem to be serious consideration in Europe….. any forums at AERO where pointed questions on this could be asked?
AFAIU the number of DME stations is on the rise, precisely so that DME/DME RNAV can be a viable alternative to GPS.
But are the number of DME’s on the rise in the USA? My guess is no as operators are pulling them out. If there is no market for a new Garmin DME product in the USA then there is no market.
Out of interest how difficult would a NAV/COM/DME box be? Presumably the DME hardware is quite complex?
Bathman wrote:
But are the number of DME’s on the rise in the USA? My guess is no as operators are pulling them out. If there is no market for a new Garmin DME product in the USA then there is no market.
If you are referring to the number of DME ground stations in the US, they are rising as DME/DME is the backup for GPS. About 1/3 of the VOR are being removed in the US and if the site had a collocated DME, the DME in most cases remained to be used as part of the DME/DME RNAV enroute and terminal capability. In some areas, new DME are being deployed where service is sparse. In addition, many ILS localizer installations are adding DME as VOR are removed to provide conventional ground based navigation for along track fixes that go away with the removal of NDB and VOR. Also, although not a DME issue, many ILS procedures are having PBN RNP APCH requirements to join the procedure (for example a TAA) and for the missed approach procedure. The PBN RNP APCH includes RNAV 1 in the initial and missed approach segments. Localizer is still the primary navigation on the final approach segment. DME is low maintenance compared to VOR.
Garmin would be wise to develop a DME/DME RNAV sensor. Their products up to G3000 go bananas when GPS signal is lost. Red crosses on everything, including AHRS. I have first-hand experience. Only the G5000 remains usable, but one needs to ask for vectors. Flying today, I was “lucky” to be on the antique Proline21, when GPS was jammed in Western Poland. Later I had a look at gpsjam.org. It’s real. Several airliners around me reported signal loss as well.
Red crosses on everything, including AHRS
I can only confirm what loco said, it’s really surprising when the G AHRS [expletive deleted] immediately after the GPS signal is lost.
The interesting fact is that at the same time the “uncertified” D ynon antenna would stil somehow receive signals from 4 satellites!
A DME is straightforward to make, and so is a KDI572 (I looked into that one) with a modern LED display.
I don’t think terminal DME is used for INS correction, due to lower power. Quite probably they use only the more powerful DME stations.
Peter wrote:
I don’t think terminal DME is used for INS correction, due to lower power.
DME/DME is not only used for INS correction but very much as a navigation system in its own right. Terminal DMEs are used so that aircraft can fly RNP 1 SIDs and STARs using DME/DME.
E.g. Stockholm/Arlanda has – apart from the 6 (!) usual “runway end” DMEs and the DME colocated with the VOR, three terminal DME stations 4-5 NM from the airport in different directions.
I said for INS correction. Airliner requirements are the only driving force behind DME/DME.
If course you also need DME for ILS and there isn’t any “CAT3 LPV”.
Peter wrote:
I said for INS correction. Airliner requirements are the only driving force behind DME/DME.
Yes you did. And I said that airliners don’t only use DME/DME for INS correction but as a navigation system in its own right. If the purpose was only for INS correction, there would be no need to sprinkle the airport neighbourhood with DME stations, would it?
