A Center Controller and flight crew reported the Controller issued a revised route via controller pilot data link communications. The flight crew did not load the route correctly into the FMC and deviated off course towards restricted special use airspace.
Synopsis
A Center Controller and flight crew reported the Controller issued a revised route via controller pilot data link communications. The flight crew did not load the route correctly into the FMC and deviated off course towards restricted special use airspace.
Narrative
Aircraft X was uplinked a reroute that would change the fix after CABAB from FRA to SANGO. Their previously cleared route was ZZZ ZZZZZ.ZZZZZ1 ZZZZZ2 CABAB FRA FAT. I uplinked to the aircraft a new route that would read ZZZZZ1 ZZZZZ2 CABAB SANGO FAT. The aircraft was uplinked the verbiage 'AT CABAB CLEARED SANGO FAT.' The pilot began to turn left immediately after downlinking a WILCO response. I recognized this; assigned the pilot a heading; and told them they were turning towards military airspace. The pilot responded; 'we were just given a CPDLC (controller pilot datalink communications) clearance direct CABAB.' I told the pilot the clearance I saw that was issued was 'AT CABAB CLEARED SANGO FAT' in which the pilot seemed to agree and recognize their mistake. I was able to obtain a point out from JCF (Joshua Approach); so no airspace violation occurred. I then kept Aircraft X on a heading until clear of the airspace; and cleared them direct CABAB via voice.Suggestion: This issue has occurred on multiple other occasions. It appears pilots are misinterpreting the clearance; and instead of using the autoload functionality of their FMS; they manually load what they believe the correct clearance is into their FMS. While this issue was much more common when we first rolled CPDLC out; it still occurs enough to where some controllers are not comfortable using CPDLC in these instances where it should be providing a huge advantage (lengthy reroutes). I recommend better pilot training and a way to connect pilots and controllers to be able to better understand each side. I believe pilots should have an opportunity to visit ARTCCs with CPDLC enabled to see the interface and clearances we send. Additionally; reintroducing Flight Deck Training to the controller workforce is extremely essential to help bridge the gap and have a better understanding of what the pilot sees and experiences on their end. Without Flight Deck Training; there is an essential piece of communication between controllers and pilots missing.
Second reporter narrative
While at cruise we received a CPDLC clearance to proceed as filed but upon reaching CARAB cleared to SANGO then FAT. We misunderstood it as cleared direct from present position to CARAB SANGO FAT. So; as we started turn ATC intervened with a corrected heading to avoid a MOA. We clarified our clearance with ATC they then cleared us direct CARAB. Then we received a CPDLC (controller pilot data link communications) for a frequency change. After multiple attempts and no response; we contacted ATC on guard to receive a usable frequency. We then proceeded as originally filed from CARAB to FRA. After passing CARAB ATC then ask us if we were going to SANGO per CPDLC. In the confusion of the misunderstood CPDLC and original clearance combined with an unusable frequency change we momentarily deviated from route centerline.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.