Do I need DME or ADF in an IFR-certified GPS panel?

On Fri, 10 Jun 2005 03:06:48 GMT, Dave S
wrote:



Newps wrote:

Not required. You just need to have any fix of the approach in the
database.

Usually I agree with you, but I am confused here.

Why WOULDN'T you need the physical location of the DME in the database,
if you are using the distance from that location as the basis of
whatever decision you were using the DME for?

I would think it depends on the type of approach. For example, flying
the VOR/DME 23 into 6B6 (Stow, MA) I could either use distance from
MHT, leaving MHT as the waypoint, or I could use the 5.1 distance from
EGORE intersection instead. Either way, the MAP is 25.1 from MHT.

However, it appears that you do need the actual I-whatever ILS device
in the database if you're substituting the GPS for an actual DME on a
ILS/DME or LOC/DME approach. KLN94 manual, 6.2.13 - "Using GPS
Distance as a Substitute for DME on Localizer-Type Approaches" reads
"The FAA allows the use of GPS distance as a substitute for DME on
localizer-type approaches when the DME facility is stored in the GPS
database. The KLN 94 stores DME's associated with localizer-type
approaches using the navaid identifier of the approach. For example,
the DME facility associated with the ILS DME 33 approach for
Burlington International airport is stored in the KLN 94's database as
IVOE."