What was found
FLT 1358 - ANC/LAX - ATB - AFTER TAKEOFF, DURING FLAP RETRACTION, RIGHT NR 1 LEADING EDGE FLAP WOULD NOT RETRACT. TRIED TO USE ALT SYSTEM BUT LE FLAP DRIVE C/B TRIPPED. RESET CIRCUIT BREAKER AND TRIED AGAIN BUT NOT HELP. DUMPED 6,000 KILOS OF FUEL AND RETURNED TO ANC. FOUND RIGHT NR 1 LE FLAP POWER DRIVE UNIT, P/N 126344-15-1 DEFECTIVE. REPLACED PDU AND OPERATION NOW NORMAL. (M)