Date: 201706
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: B737 Next Generation Undifferentiated
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Turbine Engine
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Anomaly: Aircraft Equipment Problem Critical
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Aircraft Aircraft Damaged; Flight Crew Landed in Emergency Condition; Flight Crew Diverted; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: At FL410; with no warning; the number two engine failed. The first indication was a slight jerk to the left; as if a provisioning truck had slightly nudged the fuselage. There was no noise associated with the jerk. I immediately noticed the autothrottle annunciator flashing as well as the LOW OIL PRESSURE and ENG FAIL indications on the upper display unit. The engine had not seized. The airspeed began decreasing rapidly. I announced that we had an engine failure. The First Officer agreed and began to refer to the QRH. As he did that; I selected single engine data on the FMS and requested a descent to FL310 with Center. I told them that we had experienced an engine failure and would provide further information as we knew more. We began a controlled descent and ran the Engine Failure Checklist. The APU was available and put online for electrical power. Once the Engine Failure Checklist was complete; we discussed the possibility of restarting the engine. The failed engine indicated N1 rotation; there was never any indication of fire or vibration. Other engine parameters; according to verbiage in the QRH; indicated that an engine restart attempt was appropriate. According to the QRH; the top of the restart envelope was FL240; so we requested and were granted further descent. While we descended to FL240; I contacted the Flight Attendants and advised them that we had experienced an engine failure; were about to try to restart the engine and I would advise them of our intentions once we had tried the restart. The Flight Attendant indicated that they had noticed that we were descending early and that the passengers didn't seem to know that anything unusual was going on. I didn't specifically ask; but I recall the Flight Attendant indicating that they hadn't noticed anything unusual about the failed engine. Once in the air start envelope; we determined that we had the parameters for a windmill start. We ran the QRH procedure; but the engine would not restart. At this point; I directed the First Officer to [advise ATC] and that we would be landing at the nearest suitable airport. As we were attempting the restart; I received an ACARS message from Dispatch asking if we were having a mechanical problem. I then responded to their message stating that we had an engine failure that would not restart; and we would be diverting to the nearest suitable airport. Dispatch responded with information [on which airport] was closest; along with weather and NOTAMS. The First Officer and I concurred and informed Center that we would require an enroute descent and immediate approach. Center cleared us to the IAF and appropriate descent to cross the fix at 4000 MSL. The distance remaining allowed us just the right amount of time to brief the approach and conduct the One Engine Inoperative Landing Checklist in the QRH. While the First Officer calculated the single engine landing data; I then made an announcement to the passengers to the effect that we had an engine that was 'acting up' a little and I didn't feel safe taking it all the way to [destination]; but would be making a stop. I assured them that there was absolutely nothing to worry about and we would be on the ground in a few minutes. The single engine approach and landing were uneventful. We cleared [the] taxiway and were met by the awaiting Fire Crews. The Fire Chief made an external inspection of the aircraft; then; saying that everything looked fine; cleared us to resume taxiing to parking. Company Ground Personnel were waiting for us. We parked and deplaned the passengers. A post-flight exterior inspection of the aircraft revealed a 10-20 inch gash on the interior portion of the number two cowling. A contract Mechanic arrived to remove the cowling; and discovered a chunk of metal approximately four inches long by two inches wide had ripped from the engine case and been thrown through the cowling. There was no indication of fuel or oil leak in the engine. I contacted the Operations Center and passed all this information on to Dispatch; Maintenance Control; Chief Pilot on Call and other interested parties. I made a write-up in the logbook and left the aircraft with the contract Mechanic.     My only regret with the way everything played out was my decision to try to restart the engine. Until we were at the gate; I had no idea that the engine cowling showed damaged. According to the QRH; we had all the parameters to attempt the restart. The QRH says nothing about a visual inspection from inside the cabin. This damage to the cowling was visible from the cabin; but only if you looked as far down on the underside of the inboard side of the motor as possible. Because of this; and the fact that no passenger said anything to the Flight Attendants; I don't believe any of them noticed the damage. According to the cabin crew after the flight; they were also unaware of any damage and noted that the passengers remained completely calm throughout; as though they had no idea anything had occurred. I will also note that in this age of cell phone cameras and a news media hungry for any story regarding airline incidents; nothing at all surfaced from this entire situation. Taking all that into consideration; in retrospect; had I specifically asked a Flight Attendant to examine the engine from the cabin; the damage would have been discovered and I would not have tried to restart the engine.




Synopsis: B737 Captain reported diverting after the #2 engine failed at FL410. Post flight inspection revealed damage to the engine cowl.