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rkaplan
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Posted: Sun Feb 26th, 2006 06:37 pm |
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Attached is a screenshot from loading the KMSO ILS 11 in the Garmin 430/530.
Among the initial approach fix choices are D239Y and D340Y. What do these mean?
(Answer in following post.)
Attachment: msoils11.jpg (Downloaded 54 times)
____________________
Richard Kaplan, CFII
rkaplan@flyimc.com
http://www.flyimc.com
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rkaplan
Administrator
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Posted: Sun Feb 26th, 2006 06:39 pm |
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rkaplan wrote: Attached is a screenshot from loading the KMSO ILS 11 in the Garmin 430/530.
Among the initial approach fix choices are D239Y and D340Y. What do these mean?
D239Y means the 25 DME fix on the 239 radial.
D340Y means the 25 DME fix on the 340 radial.
The trick to understanding this nomenclature is that Y is the 25th letter of the alphabet.
____________________
Richard Kaplan, CFII
rkaplan@flyimc.com
http://www.flyimc.com
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rjq
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Posted: Tue Feb 28th, 2006 01:26 am |
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rkaplan wrote:
D239Y means the 25 DME fix on the 239 radial.
D340Y means the 25 DME fix on the 340 radial.
The trick to understanding this nomenclature is that Y is the 25th letter of the alphabet.
So I've seen this a number of times now; the position of the letter being equal to the DME mileage. Is there nothing over 26NM, or if there is/are, how are those notated?
Ron Q.
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rkaplan
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Posted: Tue Feb 28th, 2006 02:12 am |
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rjq wrote: So I've seen this a number of times now; the position of the letter being equal to the DME mileage. Is there nothing over 26NM, or if there is/are, how are those notated?
Hi Ron.
Naming of waypoints including DME waypoints is governed by the ARINC 429 standard. If a DME waypoint distance were over 26NM then an alternate waypoint name would be created as you can read in detail in the Chelton EFIS Appendix here:
http://www.cheltonflightsystems.com/PDFs/50BPilotsGuide/8-Appendix-Index.pdf
Look in particular at pages 8-53 and 8-41.
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Richard Kaplan, CFII
rkaplan@flyimc.com
http://www.flyimc.com
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rjq
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Posted: Tue Feb 28th, 2006 03:32 am |
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Hi Ron.
Naming of waypoints including DME waypoints is governed by the ARINC 429 standard. If a DME waypoint distance were over 26NM then an alternate waypoint name would be created as you can read in detail in the Chelton EFIS Appendix here:
http://www.cheltonflightsystems.com/PDFs/50BPilotsGuide/8-Appendix-Index.pdf
Look in particular at pages 8-53 and 8-41.
Thanks Richard,
Found some info close to the pages you suggest. Can't say I have access to the ARINC standards, don't like the $$$ and haven't found any public domain reprints. The Chelton naming conventions did remind me I've seen something similar before, just didn't remember. Getting old; CRS.
So it would appear we wouldn't see the generic Dxxx{A-Z} format, but a new (named) waypoint would be created instead.
Thanks again for the forums.
Ron
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