FLC SHUT DOWN ENG DUE TO FLUCTUATIONS OF THE TGT GAUGE; DECLARED EMER AND RETURN LAND.

Narrative

WE PERFORMED A PRECAUTIONARY ENG SHUTDOWN ON #2 ENG BECAUSE OF ERRATIC FLUCTUATIONS IN THE TGT GAUGE. BASED ON ALL AVAILABLE INFO AND CONSIDERATION OF AVAILABLE ALTERNATIVES; WE DECIDED THIS WAS THE MOST PRUDENT COURSE OF ACTION. THE CREW WHO HAD THE PLANE FOR THE MORNING SHIFT EXPERIENCED VIEWING THE TGT GAUGE FOR #2 ENG DROP TO ZERO. THEY DECIDED TO FEATHER THAT ENG AND WRITE UP THE PROB. WHEN WE RPTED FOR DUTY; THE MECHS EXPLAINED THEY COULD ONLY FIND A FOULED CANNON PLUG. THEY CLEANED IT; GND TESTED THE ENG AND SIGNED OFF THE MAINT RELEASE. BY THE TIME WE RECEIVED THE PAPERWORK AND ACFT LOG FROM MAINT; THE PAX WERE BOARDED AND THE LOAD MANIFEST COMPLETED. ON TAXI; THE GAUGE FLUCTUATED INITIALLY AND THEN STABILIZED AT A NORMAL READING. WE DID A RUN UP IN THE 13000-14000 RPM RANGE AND THE GAUGE HELD STEADY. BASED ON THIS; WE DECIDED TO TAKE OFF. AFTER TKOF; THE GAUGE AGAIN STARTED FLUCTUATING; NOMINALLY AT FIRST. WE CONTINUED WITH THE DEP; MONITORING THE GAUGE AND OTHER ENG INSTS. WE WERE WELL AWARE THAT THE CHKLIST DIFFERENTIATES BTWN 'REPEATED FLUCTUATIONS OF TGT' AND 'SUDDEN DROP IN TGT.' WE DECIDED TO RETURN TO HNL AND WERE GIVEN CLRNC AFTER A COUPLE OF MI TO TURN BACK. THE PROB HAD BEEN DISCUSSED WITH THE FLT ATTENDANT ON TAXI AND AFTER TKOF; AND SHE MADE THE INITIAL ANNOUNCEMENT OF THE RETURN TO HNL. I ALSO EXPLAINED TO THE PAX WHY WE WERE TURNING AROUND WHEN TIME PERMITTED. WE EXAMINED ALL FACETS OF THE GAUGE PROB AND DECIDED THE SAFEST COURSE WOULD BE TO FEATHER THE ENG; BASED ON CHKLIST PROC AND EXAMINATION OF POSSIBLE DAMAGE TO THE ENG. WE NOT ONLY HAD 'REPEATED FLUCTUATIONS' BUT ALSO SAW 'SUDDEN DROP' FROM 755 TO ZERO DEGS AND BACK. WE TRIED A PWR REDUCTION WITH NO RESULT. WE CONSIDERED ALL THE POSSIBLE SCENARIOS OF WHY WE NEEDED THE TGT GAUGE AND WHEN; EVEN IF ALL THE OTHER ENG INSTS WERE NORMAL. WE REACHED THE DECISION THAT THE SAFEST AND MOST CONSERVATIVE ACTION WAS TO FEATHER THE ENG. WE DID NOT FEEL CONTINUATION OF THE FLT WOULD IN ANY WAY BE JEOPARDIZED BY THIS ACTION; WHEREAS IT WOULD BE POSSIBLE TO 'FRY' THE ENG WITHOUT A TGT GAUGE IN THE EVENT OF A GAR. WE FOLLOWED THE CHKLIST FOR FEATHERING THE R ENG AND SECURING IT. I GAVE A PA ANNOUNCEMENT AND WE LANDED UNEVENTFULLY WITH THE EMER EQUIP STANDING BY.