What was found
AIR TURN BACK DUE TO CYAN RH HYD EDP FAIL CAS AND LOSS OF HYDRAULIC PRESSURE. WHILE COMPLETING CHECKLIST, CREW RECEIVED AN AMBER HYDRAULIC PRESSURE LOW CAS, EVENTUALLY DROPPING TO 0 ON THE RIGHT SIDE. EMERGENCY DECLARED; AIRCRAFT LANDED WITHOUT INCIDENT AT KAPA. AFTER ARRIVAL, A TRAIL OF HYDRAULIC FLUID WAS OBSERVED ON THE RAMP. FOUND A RH HYD BALANCE RELIEF VALVE LINE FITTING LOOSE—SECURED HYD LINE FITTING IAW CH 300 AMM 29-12-65. HYD LEAK CHECK GOOD. SERVICED RH HYD RESERVOIR IAW CH 300 AMM 12-12-00.