What was found
CREW REPORTED HYD 3 LO PRESS INFLIGHT AND LOSS OF ALL HYD 3 FLUID PUMP 3A RAN FOR APPROXIMATELY 5 MINUTES PUMP 3B RAN FOR ABOUT 5 SECONDS CREW USED THE LEANDING GEAR EMERGENCY EXTENSION TO GET GEAR DOWN EMERGENCY DECLARED (FLIGHT 4953 - FILED CLOSED) REFERENCE AML 1982056 REFERENCE AML 1982058 FOR HYD. PUMPS AND EMERGENCY EXTENSION. INSPECTED AIRCRAFT AND FOUND LEFT WING OUTBOARD AILERON PCU LEAKING FROM MAIN PISTON SEAL. REMOVED, AND REPLACED LEFT WING OUTBOARD AILERON PCU IN REFERENCE TO AMM 27-14-01 OPS AND LEAK CHECKS GOOD AT THIS TIME. COMPLIED WITH CARD 27-900-1002-SKY AS REQUIRED OK FOR CONTINUED SERVICE.