Date: 202005
Flight conditions: VMC
Light: Daylight
Aircraft: Challenger 300
Operating under: Part 135
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class B ZZZ
Aircraft component: Indicating and Warning - Hydraulics
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Routine Inspection
Result: Air Traffic Control Provided Assistance; Flight Crew Diverted; Flight Crew Landed in Emergency Condition; Flight Crew Overcame Equipment Problem; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: During cruise and about one hour from our destination we noticed the right hydraulic reservoir quantity indication turned white; the value indicated it was on the low side but pressure remained normal. Then; we noticed it was decreasing in 2 percent increments approximately every 5 minutes with a normal pressure (3;000psi) throughout the remaining of the flight. We advised the company; the client and ATC. We looked in the FCOM Vol. 2 for some guidance and decided to get ourselves familiarize with the HYD PRESS LOW procedure listed in the QRH just in case. After assesing the situation and expecting a Hyd Press Low CAS message to come next; we decided and coordinated with the company to divert to ZZZ. We briefed the approach into ZZZ and concluded to configure the aircraft early in case we had to run any checklist. We declared an emergency upon checking in with ZZZ approach. During the configuration of the airplane; the reservoir quantity indication continued to decreased but the pressure remained normal. After fully configured the quantity was reading four percent. We landed on Runway xxR and taxiied to the FBO without incident.


Second narrative: Enroute and about 1 hour away from ZZZ1; we noticed the right hydraulic fluid quantity percentage indicator turned white. Soon we noticed it was dropping 2 % every 5 to 6 minutes; we opened up the QRH for 'L (R) HYD PRESS LOW' checklist and the FCOM 2 to find that the low level percentage for the right hydraulic system is 40% . Even though the hydraulic pressure was normal at 3;000 psi; we decided after reading thought the 'L (R) HYD PRESS LOW' checklist to deviate to ZZZ for the longer runway and [advised ATC] in case of a hydraulic failure. The quantity of the fluid kept dropping at the same rate all the way to landing and after parking at the FBO it was at 4%. Hydraulic pressure was normal at 3;000 psi all the way down. We decided not to proceed with the 'L (R) HYD PRESS LOW' checklist since the system was working properly but we were ready to utilize it and were familiar with it should the system fail last minute on short final or landing. Possible hydraulic leak No suggestions. During preflight cockpit checks; all hydraulic indications showed normal operation and no signs of leaks.


Synopsis: CL-300 flight crew reported loss of fluid for the number 2 hydraulic system; causing a diversion priority landing.