ERJ 175 flight crew reported they departed with a hydraulic system issue and were informed in flight the aircraft should not have been dispatched. After landing at destination; flight crew completed required maintenance follow-up.
Synopsis
ERJ 175 flight crew reported they departed with a hydraulic system issue and were informed in flight the aircraft should not have been dispatched. After landing at destination; flight crew completed required maintenance follow-up.
Narrative
The previous three flights leading up to the event had operated smoothly. I had received the proper amount of rest; 8 hours; I ate healthy; and hydrated throughout the day. Following a X:XX hour[s] sit in ZZZ we began our fourth and final leg of the day scheduled to depart at XA:35. We continued with normal operations and began to push back from the gate. After a normal start on both engines we ran through the after start flow. During the flight control check we received a HYD 3 LO PRES Caution message on EICAS. Up to this point our flows had been competed correctly and all systems were functioning normally. The parking break was set and we utilized company guidance to handle the situation. I advised Ground Control that we would remain on the taxiway while we dealt with the maintenance issue. I opened up the Hydraulic synoptic page and saw that Hydraulic pump 3A was not functioning. We opened up the associated QRH procedure and after turning pump 3B to ON and 3A to OFF the EICAS Caution message for HYD 3 LO PRES was extinguished; leaving two crew awareness messages; HYD 3A NOT ON and HYD PUMP NOT AUTO. At that point we discussed how operation on the backup Hydraulic 3B pump would affect operations in the event of a system 3 failure in flight. After discussion the Captain stated that he was comfortable with the situation and there was no need to return to the gate due to the message being resolved with the QRH procedure after blockout and that we can write it up on the ground in ZZZ1. I agreed with his decision and advised Ground Control that we were ready to taxi. We departed off Runway XXR without issue and proceeded to ZZZ1. In flight; the Captain sent a message to Maintenance Control advising them that he would be writing up the HYD 3 LO PRES on the ground. Maintenance Control messaged back saying; that is a no-Dispatch message; where are you?". We were unable to reply at the time due to already beginning the descent in ZZZ1. We then landed and taxied into the gate without issue. After the shutdown procedure the Captain wrote up the issue and called Maintenance Control. Cause: Looking back on the situation; my mental acuity was not as sharp as it was in the beginning of the day. Three prior legs with a X:XX hour[s] sit prior to our final leg contributed to my mental fatigue. I should have took more time to assess the situation; and be less agreeable with the Captain's decision to continue the flight rather than return to the gate. However; the flight was safely completed after following the appropriate procedures and understanding the risk of the associated maintenance issue. The policy and procedures state that the "flight is authorized to continue provided the QRH procedure corrects the irregularity." The associated QRH procedure we used resolved the Caution message and left us with the two crew awareness messages. Solution: This was my first time dealing with a Caution message after block out during my 450 hours on the line. It had been a long day and this was an unexpected threat. In the future I will be sure to slow down my decision making and be more assertive with my opinions regarding the operation of flights. I will also make sure Maintenance Control is contacted once a maintenance issue is presented after block out of the aircraft. If we had contacted Maintenance Control on the ground; rather than solving the message with the QRH procedure and operating the flight on the backup hydraulic pump; we would have known not to continue the flight and to return to the gate."
Second reporter narrative
We were starting leg four of four after a X+ hour sit in ZZZ with the flight scheduled to depart at XA:35. The day had been uneventful thus far and I had attempted to take a nap in the crew quiet room. I was unable to rest in the quiet room as it smelled like a locker room; could hear the jet bridge alarms; and I could hear all the vehicles driving by next to the building. During the sit I ate a fairly healthy meal warmed up in the microwave. Once we got to the plane and started it up; the Flight Data Recorder had some issues to which it was a non-issue after writing it up. As we neared departure time; we were informed of a connection hold which likely caused our X minute delay as we had to wait for the cargo to be finalized. We continued with normal operations and started pushing back. As we pushed back; we started the engines and everything was normal. When performing the flight control test; we got a HYD 3 LO PRES message on EICAS. Up to this point; flows had been done correctly and HYD 3a was in the on position. We used the team model to work through the problem with the parking brake set and let ground control we would need some time to work out the problem. We opened the synoptic page and saw Hydraulic pump 3a was not functioning; opened the QRH and ran the procedure. The procedure had us turn pump 3b on and 3a off; this solved the caution message and left us with two advisory messages: HYD 3A NOT ON and HYD PUMP NOT AUTO (both crew awareness messages). At this point we discussed how the lack of this pump would affect system operations and looked at the tree of QRH procedures to determine if we needed to return to gate. Based on the resulting loss of a backup pump for system 3; we decided the ramifications were not limiting to the completion of the flight. I made the decision to move forward and continue the flight with the understanding that our flight controls would be limited to hydraulic systems 1 and 2 maintaining flight controls should system 3 become inoperative; eg; backup hydraulic power to RH [control surfaces]" would not be available. On a personal note; I did not have the same mental acuity as when the day started; there was some target fixation on wanting to finish the work day; and a little pressure to rush due to the delay. We continued the flight with no issues and I sent a message to Maintenance Control to inform them of the issue and they raised concerns about my decision to continue the flight which was very distracting during the flight. Once we were approaching our destination; we focused on the safe completion of the flight over discussing maintenance controls messaging. The rest of the flight was uneventful; we made it to our destination with no issues; and I wrote up the issue per FOM describing a maintenance issue after block out. Cause: A flight was completed after following procedures and using discretion understanding the risks of the associated maintenance issue. The policy and procedures state that the "flight is authorized to continue…provided the procedure corrects the irregularity." In this case the QRH caused the caution message to extinguish and the advisory messages were crew awareness to which we had assessed the risks.Solution: If we are not to fly with the QRH solving the problem and understanding the risks after block out; it should be documented and communicated. A distinction between a "necessary" piece of equipment such as a backup hydraulic pump and solving the resulting message prior to takeoff should be made in the way mechanical irregularities are to be managed. Take away the human factor of decision making in broken equipment. Based on reviewing more information; the lack of the 3a pump would be one step closer to an NTSB reportable item and would have been a no-fly item."
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.