Date: 202007
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Night
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class B ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Turbine Engine
Component problem: Failed; Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Troubleshooting; Workload
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Flight Crew Inflight Shutdown; Flight Crew Landed in Emergency Condition; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: I was pilot flying during a clear night flight going into ZZZ. As we were in a 1000FPM descent on the arrival; we received direct ZZZ. The FMC determined we were high and throttles started moving towards the idle position. As the throttles were in transition to idle I felt a light abnormal vibration. Looking down at the engine indications; I saw N1 and N2 decreasing; followed by ENG FAIL displayed on our EGT for the #1 engine.The Captain obtained the Engine Failure or Shutdown QRH and gave me the radios; as I was already pilot flying. The CA (Captain) notified ATC that we had an engine failure but did not declare an emergency. At this time; our EGT indicator was reaching its max limitation and the CA made the decision to move the start lever to cutoff; prior to reaching this step in our Engine Failure checklist; to try and prevent exceeding our EGT max limitation. Continuing with the Engine Failure Checklist; we reached the engine restart portion; at which point the CA decided to do an In-Flight Restart. I stated that we exceeded the EGT limit and because of that; I questioned if we should restart the engine. The CA felt comfortable proceeding and explained that when restarting; or if at any point; we see the EGT rapidly increasing or approaching its limitation; we would shut the #1 engine down. I agreed with his plan; and ultimately felt we could still maintain a safe operation. The CA proceeded through the In-Flight Start Checklist. The start was successful and indications were normal. At this point; we were still descending and being vectored onto approach. I believe we were on about an 18 mile final. I began to configure early and when bringing throttles up; we felt a light vibration again. We decided to continue the approach in a partial single engine configuration with the left throttle at idle thrust; when the left throttle was at idle; there was no vibration and the engine indication were within parameters. We felt it was safer to keep the engine at idle rather than shutting it down during this phase of flight. When we felt the vibration after the second engine start; we notified ATC to contact ARFF (Aircraft Rescue and Fire Fighting) to meet us as a precaution. Previously; the CA had pulled up performance numbers for single engine approach and flaps 15. Additionally; the runway was 12250ft; so we both felt comfortable landing with our configuration. The CA ran the single engine landing checklist and I landed the airplane. After landing; I did my after landing flow; the CA shutdown the #1 engine and we taxied to the gate.Looking back on this event; I would have changed a few things. First; I would have [requested priority handling] as soon as ATC was notified that we lost an engine. Second; rather than restarting the engine after it had exceeded its limitation; I feel we could have left the engine shutdown and proceeded single engine. Third; despite having been very busy; we should have notified the FA's (Flight Attendants) and Dispatch.




Synopsis: First Officer reported an uncommanded inflight engine shutdown; causing a partial single engine landing.