Substitute DME for GPS?

Dave Butler wrote in message ...
Mick Ruthven wrote:
Some certifiec IFR approach GPS units don't contain the localizer as a
waypoint, so you can't get the LOC distance (required for some LOC/ILS
approaches) directly.

Which ones don't have the localizer as a waypoint?

The Northstar M3 Approach, for one.

John Hamilton wrote:
The lat/long for airports is called the ARP (airport reference point),
usually located near the geographic center of the field. The localizer
is at the far end of the runway. If the approach calls for a DME from
the localizer, you cannot use GPS because there is no coordinate for
the localizer antenna array.

You're making a big assumption here, that a GPS doesn't have the localizer-DME
in its database.

Someone posted that the Northstar M3 does not have localizer DMEs in its database.

The two approach-certified GPS receivers that I've used, the UPSAT GX50 and the
Garmin 430, both -do- have localizer-DME locations in their databases.

Note that for a long runway, like the
11,500 foot long runways at KPIT, it could be more than a mile from
the end of the runway to the ARP.

The FAA is working to determine coordinates for these antennas, I have
heard.

As posted by others, the locations of the DME antennas are well known by the
FAA, and in fact are available in (some? many?) GPS reciver databases.


Otherwise, your GPS will be more accurate than regular DME for VOR.

One is the Trimble Approach 2000 GPS.

"Dave Butler" wrote in message
...
Mick Ruthven wrote:
Some certifiec IFR approach GPS units don't contain the localizer as a
waypoint, so you can't get the LOC distance (required for some LOC/ILS
approaches) directly.

Which ones don't have the localizer as a waypoint?

Thomas Borchert wrote in message ...
Hi all,

a question that has probably been asked before, but I couldn't find it
in Google:

Is it allowed to use an IFR-approach-certified GPS instead of a DME in
a LOC-DME or VOR-DME approach that does not have a GPS-overlay?

Thanks!

Thomas,

in Canada, clearly yes. Approved GPS can be used in lieu of all
ground based naviagtion aids as stated in the A.I.P. 3.16.4.3.1. "GPS
may be used to identify all fixes defined by DME, VOR, VOR/DME and
NDB, including fixes that are part of any IAP, to navigate to and from
these fixes, ..." The only exception *may be* NDBs used for Missed
Approach Fixes; however, just with the last revision of the A.I.P. the
was some change in wording.

Do you know the rules in other European countries?

Gerd

Gwengler,

Do you know the rules in other European countries?


Germany: No. DME required in all IFR-certified (yes, there is such a
thing) aircraft, no matter whether the pilot plans to use approaches or
procedures that require DME or not. ADF only required in IFR training
aircraft. Ask Cirrus, they know very well how to add a remote DME box
to their avionice by now, from all the aircraft going to Europe.

--
Thomas Borchert (EDDH)