Date: 201912
Local time of day: 1801-2400
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Night
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: CTAF ZZZ
Aircraft component: Engine
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Workload
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Critical
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Landed in Emergency Condition; Flight Crew FLC complied w / Automation / Advisory; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: While cruising at FL320; #2 engine made a loud 'boom' sound; N1 dropped about 20%; and vibration commenced. Autothrottle disengaged on its own. After testing thrust lever modulation to confirm engine vibration; I directed First Officer to accomplish ENGINE HIGH VIBRATION QRH checklist. Requested priority handling with ATC. There was never a non-normal indication on the #2 vibration gauge (it never displayed above 0.8) but vibration was obvious. With #2 thrust lever at idle position; vibration largely ceased and engine remained at idle for remainder of flight. I ran TEST with purser and made PA to passengers. First Officer attempted to contact Maintenance Control through ARINC but that ultimately proved difficult and I directed him to abort that effort to support me for arrival. Workload management at times was somewhat challenging. I directed First Officer to perform ONE ENGINE INOPERATIVE QRH checklist. Remainder of flight was run per single-engine SOP. Approach and landing uneventful. I had forgotten to select an autobrake setting but the aircraft stopped easily with manual braking. Excellent support from airport emergency services once on the ground. Fire crews looked at engine and noted no visible defects. Uneventful taxi to gate except that engine generated notable smoke cloud at shutdown; which was noted by fire crew. We deplaned passengers via jetway.


Second narrative: Cruise just before top of descent into ZZZ heard pop; felt jolt; saw #2 engine drop 20-25% n1 auto throttle kicked off; airplane vibrated. All engine instruments returned to normal. Airplane continued to vibrate. Requested priority handling with ATC. QRH ran high engine vibration checklist when engine at idle no vibration. Left it at idle continued to 26;000 ft. single engine drift down altitude and continued to ZZZ. Ran 1 engine inoperative approach and landing checklist. Landed in ZZZ Runway XX somehow missed setting autobrakes. Quickly realized after touching down and brought aircraft to a stop turned off on Taxiway X and onto Taxiway Y. Checked out by fire crew. Tower said they saw sparks from #2 engine on touchdown. Trucks followed us in after saying they saw nothing abnormal. Shut down. Talked to maintenance. They said it was a major bearing failure.


Synopsis: B737 flight crew reported an engine failure during cruise resulting in a diversion.