What was found
FLAMES/SPARKS WERE OBSERVED FROM BOTH INSIDE & OUTSIDE #1 ENGINE AFTER START WHEN POWERING UP FOR TAXI. GROUND PERSONNEL REPORTED IT TO BE SEVERAL FEET FOR AT LEAST 30 SECS. FIRE/CRASH CHECKED BUT SAW NO INDICATION. NO INDICATIONS FROM ENGINE INSTRUMENTS. GROUNDED - YES. REMOVED PRIMARY NOZZLE ASSY IAW AMM 78-11-01-000-802-F00, AFT PLUG IAW AMM 78-11-02-000-802-F00, FLAME ARRESTOR ASSY IAW AMM 72-56-00-000-802--F00, & FLANGE ASSY IAW AMM 72-56-00-000-802-F00. R & R OIL SUPPLY AFT SUMP TUBE IAW AMM 72-56-00-300-801-F00. INSTALLED (TRF) OIL INLET COVER IAW AMM 72-56-00-400-801-F00. PERF POWER ASSURANCE TEST & AFT SUMP INSP IAW MIG 2C TSR 711846 C/W ITEM 1 THROUGH 8. REF AMM 71-00-00-813-F00, NO DEFECTS NOTED.