Date: 201511
Local time of day: 1201-1800
Location: ZZZZ.ARTCC, FO
Flight conditions: VMC
Light: Daylight
Aircraft: B757 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Aircraft component: Turbine Engine
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown
Second reporter function: Pilot Flying; Captain
Anomaly: ATC Issue All Types; Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Landed in Emergency Condition
Contributing factors: Aircraft; Procedure
Primary problem: Aircraft

Narrative: I was the Second Officer on this flight; but the First Officer was on his break in the cabin when the event occurred. I was the Pilot Monitoring in the right seat. Captain was the Pilot Flying. En route the left engine abruptly rolled back and failed. Captain told me to [notify ATC] and start the checklist. On Control; I announced '[my intentions to ATC] with an engine failure and requires immediate descent.' It took a few radio calls for the controller to understand that we needed lower immediately. He advised unable lower because we had traffic 1;000 ft below us opposite direction. At this point Captain began a left turn off the airway to avoid the traffic as we started down. We again told the controller we were an [priority] aircraft and advised him we were now descending and in the left turn off course. I believe we received two TA's in the initial descent. I did see one aircraft opposite direction below us but we were well clear. I ran the 'Engine Failure or Shutdown' checklist and we discussed which alternate airport would be the best. We agreed ZZZ would be the best choice because I had been there many times; it was in a radar environment; had a long runway; and we were headed in that direction. It was approximately 100 miles away. ZZZ airport was closer but it was behind us; in a non-radar environment with high terrain and neither of us had been there. We advised [ATC] that we requested diversion to ZZZ1. He cleared us direct and shortly thereafter handed us off to [the next] Control. We decided not to attempt restart. N3 was zero and also we received a few shudders in the airplane and flight controls immediately after the engine shutdown. Once we got the situation under control; I called the lead flight attendant; advised her of the situation; and asked her to call FO back to the cockpit. I advised the company using the Diversion prompt of ACARS that we were diverting to ZZZ1. I also followed up with two more ACARS Free Texts advising we had an engine failure and that that we were diverting to ZZZ1. Once FO was back in the cockpit; I stayed in the right seat and continued Pilot Monitoring duties. Crew gave the flight attendants more detail of the situation; made a PA; and advised operations; and backed us up on the checklist. We set up for the visual backed up by the ILS to 17. Weather was good there and made an uneventful single-engine landing. The fire truck and ambulance was standing by for our landing. Station operations personnel should be commended for how well they handled this situation. They were incredibly efficient with very little notice of our arrival.Engine failure - unknown cause at this point.


Second narrative: Engine failure at FL390 while en route; cause unknown. [Notified ATC] and diversion to ZZZ1. All checklists were completed and followed. The landing was uneventful.


Synopsis: B-757 crew experienced engine failure en route. Crew was unable to obtain descent clearance from ATC. Crew turned off track and began drift-down descent. Crew diverted and landed safely.