Citation X (C750)
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 100; Flight Crew Total 3450; Flight Crew Type 1050
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Provided Assistance; Flight Crew Diverted; Flight Crew Landed in Emergency Condition; Flight Crew Overcame Equipment Problem; General Maintenance Action; General Flight Cancelled / Delayed
Aircraft
In cruise; we got a HYD A Volume Low message; it was down to 15%. We monitored and continued per the checklist. We discussed the possibility of losing more fluid on the landing gear deployment and continued flight. We were scheduled to land at ZZZ (7000 ft. runway); but both agreed that if the volume dropped below 10% we would divert to ZZZ1 in order to use the 11;000 ft. plus runway. This was just in case we were to lose all the remaining fluid volume upon thrust reverser deployment and use of brakes; which would force us to use our emergency/air brakes; significantly increasing our stopping distance. When we deployed the gear the volume dropped to 8% so per our plan diverted to ZZZ1 where we landed without incident.
Air Taxi Captain reported main hydraulic system A had a decreasing system quantity; causing a diversion.