A330
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Confusion; Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Procedure; Human Factors; Aircraft
Flight was from LAX to ZZZZ. During FMS loading we checked the downlinked flight plan vs the paper flightplan and Jepp plates and they all matched.When the KUSA clearance came in via CPDLC there was a route change. (Cleared to IGOTT VIA ZILLI LAUER+Load new rte to IGOTT+).We printed the clearance; and uplinked it into the secondary route on the FMS. We then checked the secondary vs the printed revision and the Jepp plate and accepted it.We then got the same CPDLC clearance again (and another load prompt). They all matched.We then copied the secondary route to the primary.But then I noticed two green lines on the pilot map display and thought the two routes loaded sequentially; so I cleared what I thought were the duplicate waypoints.As we were climbing after ZILLI; the Center Controller asked us if we were flying ZILLI.BEAUT; and I looked at our map display and told the FO to reply 'affirmative.'The Controller then said 'OK; turn right heading 210' and nothing more. A few minutes later he said 'can you verify your clearance.' I retrieved our CPDLC clearance and realized we were not flying the assigned clearance.In retrospect I believe that I had deleted the first part of our route (the revised segment) while leaving the original segment in the FMS.Cause: Assuming the revised route had been uplinked twice; and then deleting the top waypoints without double checking the remaining waypoints.I have had multiple CPDLC clearance revisions over the last few years; and they usually don't uplink properly; so I was surprised when this one did (or so I thought).I thought I had been diligent in checking the printed route with the uplinked route and Jepp plate route; but obviously not enough. In order to prevent this type of uplink/pilot error from happening again; I think the safest course of action is to NOT to uplink the revised route; but instead print it; enter it manually; and then 'clean up' (delete) the 'old' waypoints; and THEN check the entire route against the revised printout and Jepp plate.
A330 Captain reported a track deviation occurred on a trans-Pacific flight after the CPDLC clearance was not loaded properly.