B737-800 flight crew reported the failure of the #2 EDP in flight with the subsequent loss of both main hydraulic systems resulting in a diversion.
Synopsis
B737-800 flight crew reported the failure of the #2 EDP in flight with the subsequent loss of both main hydraulic systems resulting in a diversion.
Narrative
For some historical context; we were flying turns out of ZZZ1 the day prior to our event and witnessed an emergency aircraft that had landed and was waiting off the gate for brake cooling. As we taxied past; we noticed there was a large amount of fluid pooled on the taxiway underneath the right engine. We would come to learn that this aircraft had a loss of Hydraulic System B. The next morning; we reported for our flight at ZZZ1. When we began our preflight duties; Maintenance Personnel came and retrieved the logbook stating there were write ups that needed to be reviewed. We continued boarding the aircraft; got to our scheduled departure time and the logbook had not yet been returned. While we were discussing this; the Captain noticed and brought to my attention that the 'Flap Inhibit' switch was toggled active. We had figured at that point that this aircraft was likely the same aircraft we saw the day prior. Approximately 10 minutes after our scheduled departure time; the logbook was returned; reviewed; and the appropriate checklists completed. We discussed with the Maintenance Personnel that the # 2 engine driven hydraulic pump had been replaced overnight and a ground run had been performed. We departed the gate shortly after this. There were no anomalies on the engine start; taxi; or warmup period. After the takeoff sequence; as the pilot flying (PF); I called for the landing gear to be selected up. While the landing gear retracted; there was a momentary Master Caution light and I saw HYD illuminated on the recall panel. It lasted for less than one second. The hydraulic indications were all normal. During the climbout; we discussed that during the ground run; the landing gear would not have been cycled and that this may have caused the momentary Master Caution/HYD light.We continued the climb and approximately 15-20 minutes into the flight (abeam ZZZ2); the Master Caution light illuminated again with a Low Pressure light illuminated on the ENG 2 HYD Pump. We ran the QRH procedure; which had us place that pump in the OFF position. The quantities and pressures were both still normal at that point. We discussed our options and contacted Dispatch. We felt that continuing to destination was the best course of action. We spent the next 30 minutes or so discussing different scenarios about system failures; reviewing the QRH procedures; etc. I would like to point out that the Captain was very knowledgeable with the systems and it was a great learning experience as I have about 270 hours in type. During this discussion; we noticed that the Hydraulic System A was now indicating 78%. When we departed it was >90%. I wrote down the quantity and time on the ATIS sheet so that we could track the fluid level. Over the next 20 minutes or so; we determined that we had a slow leak of about 2% every eight to nine minutes. I calculated that we would land in ZZZ3 with about 55 to 60% fluid quantity in System A. While we were discussing the now escalating situation; the Hydraulic System B fluid quantity went from 106% to 0% in about 30 seconds. We now had a complete loss of System B with what we believed to be a slow leak in System A. We immediately decided to [request priority handling]; notified Center and requested immediate descent and vectors to ZZZ. We ran the loss of System B QRH procedure; walked through an Approach Brief discussing the nuances of our failed systems and how we would configure. I flew the aircraft and talked to ATC while the Captain coordinated with Dispatch; the Cabin Crew; and ran the QRH. The approach and landing were uneventful.
Second reporter narrative
Divert due to hydraulic system failure. Probationary First Officer (FO) did a great job.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.