What was found
AFTER THE NR 1 ENGINE STARTED, NR 1 OIL FILTER BYPASS LIGHT ILLUMINATED FOR APPROX 10 SECONDS, AFTER LIGHT WENT OUT, IT ILLUMINATED 2 MORE TIMES FOR APPROX 5 SECONDS. ALL OTHER ENGINE INDICATIONS NORMAL. POWER AT IDLE DURING ENTIRE TIME WHEN LIGHT ILLUMINATED AND WENT OUT. ACFT GROUNDED. WHILE PERFORMING MAINTENANCE PROCEDURES, FOUND ALUMINUM CONTAMINATION OF THE THE NR 1 ENGINE SCAVENGE OIL FILTER. INSPECTED THE ENG SUPPLY FILTER IAW AMM 79-21-03 AND MCDS IAW AMM 79-00-00-200-804-F00, NO CONTAMINATION NOTED. FOUND NO CDU FAULTS, NO CLOGGED INDICATION SHOWN AND NO OTHER FAULT CODES FOUND. VERIFIED POP OUT INDICATOR NOT EXTENDED. R & R THE NR 1 ENGINE SCAVENGE OIL FILTER IAW AMM 79-21-06, AND OIL SUPPLY FILTER IAW AMM 79-21-03. REPLACED THE NR 1 ENGINE SCAVENGE OIL FILTER CLOGGING TRANSMITTER S125 IAW AMM 79-21-07, NO LEAKS NOTED AND OPS CHECKED GOOD.