ADS vs. ETP Lat/Long
Thread Starter
Joined: Mar 2007
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From: USofA
ADS vs. ETP Lat/Long
I'm trying to locate a point of reference for this subject. I'm constantly seeing oceanic flight plans with the ETP coordinates embedded within the flight plan legs data. Other than common sense I cannot find anything that prohibits this practice and it would seem obvious that any other flight plan routing than the exact ICAO waypoints would be out of bounds for any type of CPDLC/ADS flight following.
If any of you have a source that you can point to, I would appreciate it if you can pass it along.
If any of you have a source that you can point to, I would appreciate it if you can pass it along.

Joined: May 2005
Posts: 1,198
Likes: 32
From: France
I've seen the same problem with UVair flight logs. Really annoying; however, you don't have to put the ETP waypoints into the FMC. If you restrict the FMC waypoints to the ATS flight plan / clearance, you shouldn't have any trouble with CPDLC/ADS.
Similar problems can occur if you are cleared 'direct to' a wpt and use the 'abeam' function for fuel checks, etc. CPDLC will send loads of unnecessary position reports. Better to copy into RTE 2 (if you have one) and use this for the abeam checks.
The best flight logs give you the basic waypoint sequence and then publish ETP/PNR info on a separate page.
Don't think I can answer your actual question though, as I've never seen a reference. As you say, it just seems like common sense.
Similar problems can occur if you are cleared 'direct to' a wpt and use the 'abeam' function for fuel checks, etc. CPDLC will send loads of unnecessary position reports. Better to copy into RTE 2 (if you have one) and use this for the abeam checks.
The best flight logs give you the basic waypoint sequence and then publish ETP/PNR info on a separate page.
Don't think I can answer your actual question though, as I've never seen a reference. As you say, it just seems like common sense.


Joined: Sep 2003
Aviation Qualifications: ATPL
Posts: 956
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From: away from home
We donīt insert the ETP points into the FMC, they are after all not part of the clearance and need not be there. If you want to monitor those points, you can either use RTE 2 (Honeywell) or insert them after the destination airport leaving a discontinuity. Then they will show on the screen but not affect any calculations.
But as Spooky 2 says some flight plan formats are a bother
But as Spooky 2 says some flight plan formats are a bother
Joined: Oct 1999
Posts: 20
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From: 30W
A good reason for not inserting ETP's into the FMS, or whatever system is being used for
Navigation, is that it can and has lead to Gross Navigation Errors.
The ICAO NAT Working groups did include some advice regarding this in some of their
publications, let me see if I can remember where; from memory though it was just advice
and not a specific dictat.
Navigation, is that it can and has lead to Gross Navigation Errors.
The ICAO NAT Working groups did include some advice regarding this in some of their
publications, let me see if I can remember where; from memory though it was just advice
and not a specific dictat.





