What was found
(CAN) LANDING GEAR DID NOT RETRACT, AFTER GEAR UP SELECTION ALL GEARS DID NOT RETRACT FOR APPROX 3 MINS. ALL GEAR THEN RETRACTED. ONCE GEAR UP AND LOCKED A NR 2 HYD PUMP CAUTION AND A PTU FAIL LIGHT ILLUMINATED. THESE THEN RESET WITHOUT INTERACTION. PILOT DECIDED TO RETURN TO BASE. A NORMAL GEAR EXTENSION WAS COMPLETED. AIR FOUND IN NR 2 HYD SYSTEM. FLUID QTY DOWN 2 QTS. ELEVATOR PCU LEAKING.