Narrative:

Aircraft status ccs rdc 8 aft ee bay - ccs remote data concentrator 8 failed. Noted IRU left drift delta value increasing to 4.2. Initiated unreliable nav checklist and began post position plotting. Plot confirmed we were on course with LNAV/vnav active modes; anp 0.03 GPS updating. ATC requested us to confirm back on route. Earlier; other crew pair requested and received left 40nm weather deviation at [time] and reported back on route at [51 minutes later].confirm assigned route.nfff ATC message: ads indicates that you're approx. 40 miles right of route. We confirmed on route cross track error 0.0 GPS updating with anp 0.03. Nfff ATC message: ads still showing deviation slightly right of route. (We still showed on course with anp 0.03.) EICAS: elec gen off R2 followed by pack right alerts. Also had heat pitot C and no land 3 EICAS which cleared up with gen and pack resolutions. (Heat pitot C remained as a status message). Noted heading hold roll mode with power interruption; returned to LNAV.completed both checklists restoring gen with R2 gen ctrl reset per the non-normal and pack restored using air condition reset per the non-normal checklist. Flight attendants informed/briefed about air and electric issues and normal systems restored. Consulted [maintenance control] through dispatch and talked to 787 fleet management via sat phone.IRU left continued to show drift up to 4.9nm and IRU right had no values. GPS was updating and anp remained 0.03. Confirmed with brisbane ads B position showed us on route. Suspect ads data earlier was erroneous due to non-normals experienced. Anp with the GPS updating never exceeded 0.03 and we remained on magenta line in LNAV/vnav.excellent crew CRM!

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Original NASA ASRS Text

Title: Boeing Pilot reported navigational problems.

Narrative: Aircraft status CCS RDC 8 AFT EE BAY - CCS Remote Data Concentrator 8 failed. Noted IRU L drift delta value increasing to 4.2. Initiated Unreliable Nav checklist and began Post Position plotting. Plot confirmed we were on course with LNAV/Vnav active modes; ANP 0.03 GPS updating. ATC requested us to confirm back on route. Earlier; other crew pair requested and received left 40nm weather deviation at [time] and reported back on route at [51 minutes later].Confirm Assigned Route.NFFF ATC message: ADS indicates that you're approx. 40 miles right of route. We confirmed ON Route cross track error 0.0 GPS updating with ANP 0.03. NFFF ATC message: ADS still showing deviation slightly right of route. (We still showed on course with ANP 0.03.) EICAS: Elec Gen Off R2 followed by Pack R alerts. Also had Heat Pitot C and No Land 3 EICAS which cleared up with Gen and Pack resolutions. (Heat Pitot C remained as a Status message). Noted HDG HOLD roll mode with power interruption; Returned to LNAV.Completed both checklists restoring Gen with R2 Gen CTRL reset per the non-normal and Pack restored using Air Condition Reset per the non-normal checklist. Flight attendants informed/briefed about air and electric issues and normal systems restored. Consulted [Maintenance Control] through Dispatch and talked to 787 Fleet Management via SAT phone.IRU L continued to show drift up to 4.9nm and IRU R had no values. GPS was updating and ANP remained 0.03. Confirmed with Brisbane ADS B position showed us on route. Suspect ADS data earlier was erroneous due to non-normals experienced. ANP with the GPS updating never exceeded 0.03 and we remained on magenta line in LNAV/Vnav.Excellent crew CRM!

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.