Date: 202002
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: B737 Next Generation Undifferentiated
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
ATC / advisory: TRACON ZZZ
Aircraft component: Hydraulic Main System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Second reporter function: Pilot Flying; First Officer
Anomaly: Aircraft Equipment Problem Critical
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Climbing through 10;000 ft.; we received a Master Caution with a 'LOW PRESSURE' light illuminated over the Engine Driven Hydraulic Pump for System A. I used the QRH (Quick Reference Handbook) and completed the checklist for the malfunction; isolating the pump. Shortly after that; we noticed that the quantity indication was decreasing; and stabilized at 20%. We recognized that as a leak in the pump itself; or possibly the lines to the pump; and considered that the primary cause for the failure. As such; and given that the electric pump was operational and no other system degradation was noticed; we continued to ZZZ. We monitored the hydraulic page; and noticed that the quantity was further decreasing; at a rate of 1% every ten to fifteen minutes. We calculated that we'd land with 8% to 10%.During this time (from occurrence to top of descent); we coordinated with Dispatch and Maintenance Control. The decision to continue was supported. At the top of descent (almost immediately after starting down); the Master Caution illuminated again; this time with a 'LOW PRESSURE' light above the B system Engine Driven Hydraulic Pump. I delegated flying and radios to the FO; who was the Pilot Flying for the leg; and ran the same checklist as before. With the B system pump isolated; we noticed the quantity decreasing (initially 106%; now 80%.) It stabilized at 80% and didn't further decrease. After running the checklist; I told the FO that with two system failures that weren't at all typical; I would like to proceed direct to ZZZ. He agreed; and I did so with Approach.We were approximately 75 miles from the airport. I sent a message to Dispatch and Maintenance Control explaining the new problem. I called the Purser and told her what was happening; and discussed the [briefing] items. I told her that no cabin preparation was necessary and that we'd land in about 25 minutes. We concluded; and I made a PA to the passengers. I told them that we had a hydraulic problem; that the airplane was flying normally; but that as a cautionary measure we would be followed in by fire trucks after landing all the way to the gate; and that it was not something with which to be concerned.We got vectored for a right base and landed with no incident. On rollout; the A system quantity went to zero; and then restabilized at 12%. Nosewheel steering was normal; and braking action was normal. I elected to taxi clear of the runway and proceed to the gate with no further assistance. We ran the Parking Checklist and debriefed the flight; then per Gate Message; ran the Terminating Checklist. By that time; maintenance technicians were already inspecting the airplane. We could only see the left engine; and there was a large puddle of fluid underneath it.


Second narrative: [Report narrative contained no additional information.]


Synopsis: B737NG Flight Crew reported continuing to destination with a low pressure caution on the A system hydraulics; and as they approached destination; a low pressure caution on the B system hydraulics.