B737-800
Flight Crew Air Transport Pilot (ATP)
Flight Crew Total 12000
Troubleshooting; Workload
Aircraft Equipment Problem Less Severe
Flight Crew FLC complied w / Automation / Advisory; Flight Crew Returned To Departure Airport; Flight Crew Landed As Precaution; General Maintenance Action
Aircraft
During the climb segment of flight; we received an engine hydraulic pump low pressure light system B. A short time later we received an additional master caution to include the electric standby pump system B. System B hydraulic pressure indicated zero. The quantity also indicated zero. We [advised ATC]; completed all associated checklist and returned to the departure airport for an uneventful landing.Possibly the system B engine driven hydraulic pump failed resulting in the total loss of system B hydraulic fluid.
Upon climb out; approaching 18;000 MSL; Master Caution and HYD amber lights illuminated. Further examination showed 'Low Pressure' light illuminated for ENG 2 HYD PUMPS on Overhead Panel. Checked HYDRAULIC SYS QTY Indicators; readings showed quantity at 106% and pressure at 2870. Followed QRH procedure for Hydraulic Pump Low Pressure light. I then contacted Dispatch to notify them of the situation and decision to return. During that radio call; second 'low pressure' light illuminated for ELEC 1 pump for System B. Examination of System pressure and quantity indicated both at 0 (zero). Concluded radio call with dispatcher and notified him we were returning. [Advised] Center; reversed course to return. I took control of aircraft as PF and FO assumed PM duties. Followed QRH procedure for Loss of System B. Notified Dispatch by ACARS of return to ZZZ; asked ATC for ARFF upon landing; briefed Flight Attendants. Upon arrival for final approach; made several turns in a box pattern while completing QRH checklist and other normal procedures/checklists for arrival and landing. Notified ATC when ready to commence approach. Landed without further incident. Stopped on Runway; examined by ARFF; no signs of fire or other damage. Taxied to gate.
B737 flight crew reported the hydraulic system B low pressure alerted followed by the standby pump low pressure and eventually the hydraulic quantity alerted.