Air carrier crew reported the left center fuel tank pump failed in flight. The crew reported they had a low pressure light indication prior to departure but were assured by maintenance the recurring issue had been resolved and the indication was a faulty light.
Synopsis
Air carrier crew reported the left center fuel tank pump failed in flight. The crew reported they had a low pressure light indication prior to departure but were assured by maintenance the recurring issue had been resolved and the indication was a faulty light.
Narrative
While on the ground and doing our preflight checks for flight ZZZ-ZZZ1; we noticed the left center tank fuel pump low pressure light illuminated. This had been a recurring issue that we had seen in the logbook so Maintenance was contacted and they came to the aircraft. He reset the pump and explained that they had worked on it overnight and that it was just an issue with the light; not the actual pump itself. He told us that if the light came back on in flight; to write it up en route to ZZZ1. He then went outside; verified the pump was working again; and communicated through the ground intercom that it was indeed working properly. We took off without issue; and as we climbed out the low pressure light illuminated; and we canceled it believing it was just a faulty indicator light as he had explained. Approximately over [landmark] we noticed we had a pretty big fuel imbalance; about 1800 lbs with the left tank being the low side. The Captain handed me the controls and ran the QRH. After reading through the checklist; we decided to divert based on a few factors. First; at the end of the checklist it has you turn off the other center tank fuel pump; rendering the center fuel tank unusable. There was roughly 5 to 6;000 lbs in there at the time; and we felt we would not have enough fuel in the wings to continue to ZZZ1. Also; the left center tank had failed which was also the side of the imbalance and the 'low side'. The imbalance checklist also rendered all fuel pumps on the left engine shutoff; which created a concern of solely suction feeding that engine from a high power setting. These factors led us to divert to ZZZ2 where we landed without incident as a non-emergency divert. Maintenance met the aircraft at the gate and performed the necessary checks and write ups- including placing it under MEL; which required several maintenance functions. We departed for ZZZ1 shortly thereafter.
Second reporter narrative
While on the ground in ZZZ; the left center tank fuel pump low pressure light illuminated. Maintenance was contacted as this was a repeat write up that had just been cleared. Maintenance came to the aircraft and reset the pump saying it was only a pump indicator light that was faulty. The mechanic went outside to verify that the pump was running and notified us via intercom that we were good to go as the pump was operational. He mentioned that if the light came back on to write it up en route to ZZZ1. After takeoff; the left pump low pressure light illuminated once again but it was canceled believing it was only the indicator light that was malfunctioning. Passing through 23;000 feet we noticed a fuel imbalance of almost 1800 lbs with the left main tank being low. The checklist for fuel pump low pressure light and fuel imbalance were completed. The checklists had all fuel pumps on the left engine shut off and this created a concern about solely suction feeding that engine at a high power setting. Additionally; due to the potential for the center tank fuel to become unusable if the second center pump failed; the decision was made to divert to ZZZ2 to have the problem resolved. Upon arrival at ZZZ2; we wrote up the malfunction and maintenance boarded the aircraft. They verified that the left pump would be deferred and we received a new Maintenance Release. We departed for ZZZ1 shortly thereafter.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.