B757-200 FLT CREW IS RELUCTANT TO RETURN AND LAND OVER MAX STRUCTURAL LNDG WEIGHT AT DEP ARPT FOLLOWING ABNORMAL LEFT ENGINE EGT INDICATIONS ON TKOF.

Narrative

ON TKOF; L ENG EGT FLUCTUATED THEN SPIKED FROM 795 DEGS C TO AN OVERTEMP CONDITION AT 871 DEGS C. AT 1000 FT AGL; SELECTED CLB THRUST/VNAV. WHEN VNAV SELECTED; TMC IMMEDIATELY DEFAULTED TO MAX CONTINUOUS THRUST. DISCONNECTED AUTOTHROTTLES. SELECTED SPD INTERVENTION 250 KTS AND CLB THRUST AGAIN. RE-ENGAGED AUTOTHROTTLES AND RESELECTED VNAV. TMC AGAIN DEFAULTED TO MAX CONTINUOUS THRUST AND ORANGE SPD BUG DECREASED TO VREF +80 KTS. DISENGAGED AUTOTHROTTLES. DURING REMAINDER OF CLBOUT; L ENG PARAMETERS REMAINED NORMAL. OUT OF 10000 FT; CONTACTED MAINT CONCERNING MECHANICAL FAILURES. RECEIVED ACARS MESSAGE 'RETURN TO FIELD BECAUSE IF YOU CONTINUE IT WILL REQUIRE A LONG ROAD TRIP.' RECEIVED MESSAGE FROM MAINT STATING LAND OVERWT/COMPLY WITH QRH OVERWT LNDG CHKLIST; IE; SINK RATE. REVIEWED OVERWT LNDG CHKLIST. OBTAINED ATC CLRNC TO HOLD TO BURN DOWN FUEL FOR LNDG. COMMUNICATED INDIRECTLY THROUGH MAINT WITH ZZZ CHIEF PLT CONCERNING APPLICATION OF OVERWT LNDG CHKLIST PRIME DIRECTIVE. AFTER 2 HRS HOLDING; RECEIVED ACARS MESSAGE 'YOU ARE CLR TO LAND OVERWT END.' EXPECTING TO LAND AT MAX LNDG WT; L ENG EGT SPIKED INTO YELLOW BAND AGAIN THEN RETURNED TO NORMAL. ON LONG FINAL TO RWY; ELECTED TO LAND 4000 LBS OVERWT IN LIGHT OF INTERMITTENT ABNORMAL EGT INDICATIONS.