B737-700
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Flight Crew Last 90 Days 140
Confusion; Troubleshooting
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Fuel Issue
Air Traffic Control Provided Assistance; Flight Crew Diverted; Flight Crew Inflight Shutdown; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification; General Maintenance Action
Aircraft
Upon reaching cruise altitude of FL 340; we noticed a growing fuel imbalance between the main fuel tanks (no fuel in the center tank). As the left main tank quantity was decreasing more rapidly than the right; I had the FO (First Officer) go to the cabin for a visual inspection of the area around the left engine. He returned to the flight deck and reported nothing unusual. All other flight deck switches and indications were normal.Given the rate of the growing imbalance; approaching 700 lbs less in the left versus right tank; we decided to commence the Fuel Imbalance QRH checklist. As the checklist would direct a shutdown of the #1 engine; we requested priority handling with Center and began a diversion to ZZZ. We completed the checklist as we descended; accomplished a single-engine landing; and proceeded to the gate otherwise uneventfully.
Upon reaching FL 340 cruise altitude; the Captain noticed that the left fuel indicator showed approximately 500 lbs less than the right tank. We also noticed that the left fuel indications (quantity and lbs) were decreasing faster than the right indications. It was a ferry flight with only the two Pilots and two FAs (Flight Attendants) onboard; so the Captain had me go to the rear and look for indications of fuel leak. Using the wing lights and a flashlight I carry I was unable to see any loss of fuel occurring.Upon returning to the flight deck; the Captain had the QRH out and was looking at the procedure. At this time it reached its max imbalance of 700 lbs. We executed the QRH checklist. It required the shutdown of the left engine. The Captain coordinated with ATC and requested priority handling for fuel; and we diverted to ZZZ. The descent; approach; and landing were uneventful. We executed the QRH until the procedure was complete.
B737-700 flight crew reported a growing fuel imbalance during cruise and the subsequent decision for an in-flight engine shut down and diversion to another airport.