B737 Undifferentiated or Other Model
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Flight Crew Last 90 Days 151; Flight Crew Total 10195; Flight Crew Type 10195
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Provided Assistance; Air Traffic Control Issued New Clearance; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification; General Maintenance Action; General Flight Cancelled / Delayed
Aircraft
Leaving ZZZ an engine HYD SYS (Hydraulic System) A loss light illuminated. A SYS HYD Quantity at that time was normal. After approximately 2 hours into the flight A SYS HYD quantity fell to 16%. Although the A SYS HYD electric pump was providing pressure for the A SYS; I believed that there was potential that we might experience a total loss of the A SYS hydraulics once the landing gear was extended. I [requested priority handling] and contacted Dispatch. We extended the landing gear early and it extended normally. On approach; the gear and all other systems functioned normally. Landing was normal and uneventful. We taxied to the gate and discovered that we had a major HYD leak in the A SYS pump.
B737 Captain reported loss of Hydraulic System A during cruise.