B787 pilot crew reported a failure of an engine anti-ice system while in icing conditions.

Narrative:

As we were descending into ZZZZ; we received an 'eng core anti-ice right' EICAS caution. We performed the ecl items which stated to avoid icing conditions. This directive escalated the urgency of our situation as we were already IMC in icing conditions. We were cleared to descend to FL140 and proceed to ZZZZ via the zzzzz 2F to hold as published with an efc. The ATIS indicated moderate to severe icing all holding altitudes. The captain attempted to push up the power to increase bleed air. This worked temporarily as the EICAS went away. I requested a lower altitude to avoid icing but ATC indicated expedited handling would only be available if we conveyed urgency or emergency authority. I and the [relief pilot] advocated to [advise ATC] to get out of the icing conditions. The captain felt with the EICAS not present; the situation was not yet that urgent so he directed the [relief pilot] to satcom dispatch and include [maintenance control] in on the call. I flew the aircraft and handled ATC while the captain and [relief pilot] conferred with dispatch and [maintenance control]. The decision was made to expedite our arrival to ZZZZ. We had just entered the hold at zzzzz when the satcom call ended and the captain made the decision to land immediately. We transferred aircraft control and at the direction of the captain I conveyed the 'pan pan' call to ZZZZ director to get us out of the icing due to irregular engine indications (as the captain was not sure ATC would understand our anti-ice systems). We were given vectors out of the holding pattern and when clear of the traffic in the holding stack; we were cleared to descend to FL80. We performed an uneventful cda approach to [runway] xxr. Upon landing; we were instructed to contact crash fire rescue equipment and were further met at the gate by legal authorities and the in flight supervisor. We assume either dispatch or ATC escalated our urgent pan pan call.

Original NASA ASRS Text

Title: B787 pilot crew reported a failure of an engine anti-ice system while in icing conditions.

Narrative: As we were descending into ZZZZ; we received an 'Eng Core Anti-Ice R' EICAS caution. We performed the ECL items which stated to avoid icing conditions. This directive escalated the urgency of our situation as we were already IMC in icing conditions. We were cleared to descend to FL140 and proceed to ZZZZ via the ZZZZZ 2F to hold as published with an EFC. The ATIS indicated moderate to severe icing all holding altitudes. The Captain attempted to push up the power to increase bleed air. This worked temporarily as the EICAS went away. I requested a lower altitude to avoid icing but ATC indicated expedited handling would only be available if we conveyed urgency or emergency authority. I and the [Relief Pilot] advocated to [advise ATC] to get out of the icing conditions. The Captain felt with the EICAS not present; the situation was not yet that urgent so he directed the [Relief Pilot] to Satcom Dispatch and include [Maintenance Control] in on the call. I flew the aircraft and handled ATC while the Captain and [Relief Pilot] conferred with Dispatch and [Maintenance Control]. The decision was made to expedite our arrival to ZZZZ. We had just entered the hold at ZZZZZ when the SATCOM call ended and the Captain made the decision to land immediately. We transferred aircraft control and at the direction of the Captain I conveyed the 'Pan Pan' call to ZZZZ Director to get us out of the icing due to irregular engine indications (as the Captain was not sure ATC would understand our anti-ice systems). We were given vectors out of the holding pattern and when clear of the traffic in the holding stack; we were cleared to descend to FL80. We performed an uneventful CDA approach to [Runway] XXR. Upon landing; we were instructed to contact CFR and were further met at the gate by legal authorities and the In flight Supervisor. We assume either Dispatch or ATC escalated our urgent Pan Pan call.

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.

Attributes
ACN	1644421
Time
Date	201905
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZZ.Airport
State Reference	FO
Environment
Flight Conditions	IMC
Aircraft 1
Make Model Name	Boeing Company Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Component
Aircraft Component	Ice/Rain Protection System
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 186.03 Flight Crew Total 4349.48 Flight Crew Type 1134.43
Person 2
Function	Captain Pilot Flying
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 107.43 Flight Crew Total 10362 Flight Crew Type 404.08
Events
Anomaly	Aircraft Equipment Problem Less Severe Inflight Event / Encounter Weather / Turbulence