B767-300 flight crew reported problems with one engine while descending for a landing.

Attributes
ACN	1543592
Time
Date	201805
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	IMC
Light	Dawn
Aircraft 1
Make Model Name	B767-300 and 300 ER
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Other On SID/STAR
Flight Plan	IFR
Component
Aircraft Component	Engine
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 90 Flight Crew Total 13000 Flight Crew Type 5700
Person 2
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 175 Flight Crew Total 12700 Flight Crew Type 375
Events
Anomaly	Aircraft Equipment Problem Less Severe

Narrative:

Normal flight from departure through top of descent. At TOD (top of descent); the VNAV path was captured and the aircraft started its descent. Both throttles were reduced to idle using autothrottle. I noticed a slight rumble; but though it was nothing more than some light chop (turbulence) as the throttles reduced. Once in the descent; we noticed the engine parameters were significantly different for the two engines. The left side looked normal; but the right engine N1 was 15% lower than the left; and the right egt (exhaust gas temperature) was around 400 degrees higher than the left. This was still well below any engine limits for the CF6. I tried to advance the thrust on the right engine and found it unresponsive. We subsequently ran the qrc procedure for engine limit/surge/compressor stall; which did not remedy the issue. The engine was operating at idle thrust; but no more than idle thrust was generated when requested. I opted to leave the right engine operating at idle thrust; but prepared for a 'single-engine' ILS approach to destination. We completed the engine failure/shutdown QRH procedure without actually cutting off the fuel control switch or pulling the fire handle; and proceeded uneventfully to a flaps 20 ILS approach into ZZZ. After landing; we taxied back to park without assistance. Engine was finally shut down once in parking.

Original NASA ASRS Text

Title: B767-300 flight crew reported problems with one engine while descending for a landing.

Narrative: Normal flight from departure through top of descent. At TOD (Top of Descent); the VNAV Path was captured and the aircraft started its descent. Both throttles were reduced to idle using autothrottle. I noticed a slight rumble; but though it was nothing more than some light chop (turbulence) as the throttles reduced. Once in the descent; we noticed the engine parameters were significantly different for the two engines. The left side looked normal; but the right engine N1 was 15% lower than the left; and the right EGT (Exhaust Gas Temperature) was around 400 degrees higher than the left. This was still well below any engine limits for the CF6. I tried to advance the thrust on the right engine and found it unresponsive. We subsequently ran the QRC procedure for Engine Limit/Surge/Compressor Stall; which did not remedy the issue. The engine was operating at idle thrust; but no more than idle thrust was generated when requested. I opted to leave the right engine operating at idle thrust; but prepared for a 'single-engine' ILS approach to destination. We completed the Engine Failure/Shutdown QRH procedure without actually cutting off the fuel control switch or pulling the fire handle; and proceeded uneventfully to a flaps 20 ILS approach into ZZZ. After landing; we taxied back to park without assistance. Engine was finally shut down once in parking.

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.