What was found
PILOT EXPERIENCED PROBLEM WITH HIS LANDING GEAR WHILE ON APPROACH. THE GEAR UNSAFE LIGHT FLICKERED ON AND OFF WHILE ENROUTE; WHEN GEAR LEVER WAS PUT DOWN, NOTHING HAPPENED. AFTER EXECUTING A CHECKLIST TO TROUBLESHOOT, HE DETERMINED THAT SOMETHING IN THE SYSTEM HAD MALFUNCTIONED. MAINTENANCE TROUBLESHOT PROBLEM TO A DEFECTIVE HYDR POWERPACK PN HYC5005, SN AH10437, TIS/TSO-43 HOURS, DATE OF LAST O/H MARCH 13, 2008. (K)