Narrative:

At XA40Z, we received a clearance from nadi control to deviate right off course 50 NM. At XA20Z, we received a clearance to deviate left 50 NM, both due to WX. We ultimately deviated right 30 NM. After being changed to auckland control, the nadi controller inquired if we were deviating and what direction. We informed him right off course, 30 NM and that we were back on course at that time. The nature of the inquiry caused concern on the flight crew's part that we had possibly reported back on course prior to initiating the deviation. An inventory of the cpdlc ATC log indicated we had not cancelled the deviation request. This incident brings up certain concerns of cpdlc deviation clrncs. 1) unlike block altitude clrncs where we can input flxxx/flyyy, left and right deviation requests cannot be conveniently entered in one message. We either have to submit 2 messages, one for left and one for right, or input one direction and add text for the other. I find the latter lacking as most of the time the controller doesn't read the text or understand the request and just clears the deviation to the main direction and not the one requested in the text. 2) when 2 requests are sent consecutively does the controller possibly think the second cancels or overrides the first? This might be the case in the current situation. 3) as an aside when a request is made for a deviation the clearance includes a request to 'report back on route.' this automatically puts a 'back on route' prompt in the ATC FMC page. If we ask for deviations each way in 2 separate messages there are 2 of these prompts. Is each prompt specifically related to the message, one for left and one for right? Can we delete one and send the other and then cancel both deviation clrncs or do we need to send both?

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Original NASA ASRS Text

Title: NFFF COMMERCIAL RADIO OPERATOR MONITORING WX DEVS IN SOUTH PACIFIC VIA B744 IS CONFUSED BY DATALINK COMS FROM B747-400 FLT CREW.

Narrative: AT XA40Z, WE RECEIVED A CLRNC FROM NADI CTL TO DEVIATE R OFF COURSE 50 NM. AT XA20Z, WE RECEIVED A CLRNC TO DEVIATE L 50 NM, BOTH DUE TO WX. WE ULTIMATELY DEVIATED R 30 NM. AFTER BEING CHANGED TO AUCKLAND CTL, THE NADI CTLR INQUIRED IF WE WERE DEVIATING AND WHAT DIRECTION. WE INFORMED HIM R OFF COURSE, 30 NM AND THAT WE WERE BACK ON COURSE AT THAT TIME. THE NATURE OF THE INQUIRY CAUSED CONCERN ON THE FLT CREW'S PART THAT WE HAD POSSIBLY RPTED BACK ON COURSE PRIOR TO INITIATING THE DEV. AN INVENTORY OF THE CPDLC ATC LOG INDICATED WE HAD NOT CANCELLED THE DEV REQUEST. THIS INCIDENT BRINGS UP CERTAIN CONCERNS OF CPDLC DEV CLRNCS. 1) UNLIKE BLOCK ALT CLRNCS WHERE WE CAN INPUT FLXXX/FLYYY, L AND R DEV REQUESTS CANNOT BE CONVENIENTLY ENTERED IN ONE MESSAGE. WE EITHER HAVE TO SUBMIT 2 MESSAGES, ONE FOR L AND ONE FOR R, OR INPUT ONE DIRECTION AND ADD TEXT FOR THE OTHER. I FIND THE LATTER LACKING AS MOST OF THE TIME THE CTLR DOESN'T READ THE TEXT OR UNDERSTAND THE REQUEST AND JUST CLRS THE DEV TO THE MAIN DIRECTION AND NOT THE ONE REQUESTED IN THE TEXT. 2) WHEN 2 REQUESTS ARE SENT CONSECUTIVELY DOES THE CTLR POSSIBLY THINK THE SECOND CANCELS OR OVERRIDES THE FIRST? THIS MIGHT BE THE CASE IN THE CURRENT SIT. 3) AS AN ASIDE WHEN A REQUEST IS MADE FOR A DEV THE CLRNC INCLUDES A REQUEST TO 'RPT BACK ON RTE.' THIS AUTOMATICALLY PUTS A 'BACK ON RTE' PROMPT IN THE ATC FMC PAGE. IF WE ASK FOR DEVS EACH WAY IN 2 SEPARATE MESSAGES THERE ARE 2 OF THESE PROMPTS. IS EACH PROMPT SPECIFICALLY RELATED TO THE MESSAGE, ONE FOR L AND ONE FOR R? CAN WE DELETE ONE AND SEND THE OTHER AND THEN CANCEL BOTH DEV CLRNCS OR DO WE NEED TO SEND BOTH?

Data retrieved from NASA's ASRS site as of July 2007 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.