Created a flight plan with RouteFinder EGLL-KSFO today. For North Atlantic sector the plan was ---SHA-BURAK-DOGAL-54N020W-54N030W-54N040W-53N050W-HECKK-YAY---. Had quite a lot of difficulty in determining the format for latlon waypoints but found that e.g. 54N20 was accepted by CDU for 54N020W, etc. On take off, I was repeatedly warned of insufficient fuel, but, what the heck, this is a test! So took-off successfully.Then I noticed that leg was showing over 3000 nms from DOGAL to 54N020W so used REF NAV DATA to determine where FMC thought 54N20 is. It thinks that it is at N54 0.0 W119 60.0 (somewhere in Alberta, Canada). 53N50 (my last latlon before HECKK showed as N52 13.2 W053 22.1 (somewhere in the Gulf of Alaska).I have not yet touched the navdata supplied with the release. Am I the cause of the problem in entering the waypoint names of latlon waypoints incorrectly? If not, why am I getting such peculiar placings?Regards, Richard McDonald Woods,Winchester, UK

Apologies! In post above, 53N50 showed as N53 0.0 W150 0.0Cheers, Richard

The NavData from Navigraph contains these "shorthand" fix entries in the wpNavFIX.txt file. Search for 53N20 you get: 54N20 54.000000-120.000000There is a pattern (see http://ops.precisionmanuals.com/wiki/NAVDA...ta_Dictionary):8750W 8750W-87.000000 -50.00000055S11 55S11-55.000000 111.0000000538E 0538E 5.000000 38.0000003883N 3883N 38.000000 -83.00000038N30 38N30 38.000000-130.000000DOWNS DOWNS 38.053928 -86.251583NNNNN NNNNN dd.dddddd dd.dddddd NNNNN Col 1-5 & 25-30 Fix Name dd.dddddd Col 32-40 Latitude degrees (-Lat for South, sign Col 31)ddd.dddddd Col 41-51 Longitude degrees (-Lon for West, decimal always Col 45) Note: The duplicate name fields may be the result how the FAA provides data, where there are many more fixes defined than provide in the airac data. For example, most terminal data is not included. This data includes airway crossing, radar service boundaries, etc.

Hi Dan!Thanks for introducing me to the complexities of fix naming. It seems VERY complicated but, because most of my flying is over the N Atlantic, all of my fixes will be of the form e.g. 5420W because NATs are always in northern latitudes, and the N Atlantic only goes from around 10W to 80W.Cheers, Richard

To put the record straight, I meant 5420N in the above note, not 5420W.I think I am beginning to get the hang of the naming conventions!Cheers, Richard

To put the record straight, I meant 5420N in the above note, not 5420W.I think I am beginning to get the hang of the naming conventions!Cheers, Richard

A copy of my own cheatsheet:LATITUDE/LONGITUDE NDDMM.MM/WDDDMM.MM Longform NDDWDD Shortform where minutes are zero, Longitude is 3 digits NDDDDW Shortform where minutes are zero, Longitude is 2 digitsN latitude/W longitudeN52 00/W075 00 = 5275NN50 00/W040 00 = 5040NN07 00/W008 00 = 0708NN75 00/W170 00 = 75N70N07 00/W120 00 = 07N20N latitude/E longitudeN50 00/E020 00 = 5020EN75 00/E050 00 = 7550EN06 00/E008 00 = 0608EN75 00/E150 00 = 75E50N06 00/E110 00 = 06E10S latitude/W longitudeS52 00/W075 00 = 5275WS50 00/W040 00 = 5040WS07 00/W008 00 = 0708WS75 00/W170 00 = 75W70S07 00/W120 00 = 07W20S latitude/E longitudeS50 00/E020 00 = 5020SS75 00/E050 00 = 7550SS06 00/E008 00 = 0608SS75 00/E150 00 = 75S50S06 00/E110 00 = 06S10