An air carrier captain reported a cpdlc enroute oceanic weather diversion clearance revision include...

Attributes
ACN	1397571
Time
Date	201610
Local Time Of Day	1201-1800
Place
Locale Reference	KZAK.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Widebody Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Route In Use	Oceanic
Flight Plan	IFR
Component
Aircraft Component	FMS/FMC
Person 1
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Total 10420 Flight Crew Type 6291
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Deviation - Track / Heading All Types

Narrative:

Dispatch recommended a reroute after he found that a ts he thought would not be a factor on our original route was indeed a factor. The reroute included changing n31e180 to n29e180. We requested the reroute and received it via cpdlc from kzak. We proceeded to verify the reroute and load it via the FMC load prompt. Our FMC recognizes 180 degrees of longitude as W180. Sabre and ATC recognize this longitude as E180. When we hit load FMC; apparently the FMC does not recognize E180 (sent to us from ATC); therefore it loaded n29e179 (the next closest point; I guess). Because we did the reroute load procedure properly; we caught the problem and corrected it before executing the reroute. I have subsequently looked for anything in our manuals; bulletins; etc.; about this anomaly and have not found anything.

Original NASA ASRS Text

Title: An air carrier Captain reported a CPDLC enroute oceanic weather diversion clearance revision included an E180 waypoint; but the FMC always recognizes 180° as W180. Sabre and ATC recognizes 180° as E180; a uniformity discrepancy which should be corrected.

Narrative: Dispatch recommended a reroute after he found that a TS he thought would not be a factor on our original route was indeed a factor. The reroute included changing N31E180 to N29E180. We requested the reroute and received it via CPDLC from KZAK. We proceeded to verify the reroute and load it via the FMC Load prompt. Our FMC recognizes 180 degrees of longitude as W180. Sabre and ATC recognize this longitude as E180. When we hit Load FMC; apparently the FMC does not recognize E180 (sent to us from ATC); therefore it loaded N29E179 (the next closest point; I guess). Because we did the reroute load procedure properly; we caught the problem and corrected it before executing the reroute. I have subsequently looked for anything in our manuals; bulletins; etc.; about this anomaly and have not found anything.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

An air carrier captain reported a cpdlc enroute oceanic weather diversion clearance revision included an E180 waypoint; but the FMC always recognizes 180° as W180. Sabre and ATC recognizes 180° as E180; a uniformity discrepancy which should be corrected.