Narrative:

Normal climb to cruise at FL400. Smooth and clear. At approximately over ZZZZ1 about XA50Z at FL400; #1 engine made loud bang (compressor stall); N1 dropped to about 60-70% and aircraft yawed. I disconnected the autopilot and autothrottles. Captain declared an emergency with center. Engine indications were that it was still operating (rotating N1; N2; ff; etc.) -- although at lower thrust; with no vibration under 60%; but the oil temperature was about +/-123 degrees -- that seemed higher than normal. Right engine (#2 -- good engine) was only showing 80 degrees oil temperature. I asked for the QRH (engine limit/surge stall). No loss in oil quantity or other fluids; pressures. We decided that the engine did not have severe damage that we were aware of at the idle to approximately 50% setting. So we elected to leave it running and monitored it for declining trends. There were none. During this time captain asked for descent to FL200; which we started a gradual descent and had 'continuous' displayed on the FMS N1 limit page. We tried contacting dispatch numerous times. Finally elected through ACARS and got response. We contacted the flight attendants; made a brief PA to passengers. By this time; we had already decided tht ZZZZ1 was our closest suitable airport (now 80 miles behind us). We were only 120;000 pounds (well below landing weight limit). ZZZZ1 had a 7;200 ft runway with crash fire rescue equipment. By the time we asked dispatch about their concurrence about diversion to ZZZZ1; they had started being able to hear us. They asked us to stand by for maintenance control. When they came back to us; they asked if we 'tried' using normal power again. We said no. Then; they asked if we'd considered going to ZZZZ2. Captain's response (shortened version) was 'no.' ZZZZ2 was 300 miles away. ZZZZ1 was only about 100 miles away at this point. ZZZZ3 was across the water 80 miles. We told ATC we were going to change our destination to ZZZZ1. Weather was clear and we obtained current conditions from ACARS and ATC -- and dispatch concurred. We made a 180 degree turn back for ZZZZ1 and planned the descent with FMS and appropriate charts. The captain and I discussed who should do the landing. He had the HUD; more experience; etc. So we decided that he would do the landing. During descent; the #1 engine was brought up to about 65% and we got vibration -- so we pulled it back to idle for the remainder of the flight. However; the only abnormal indication was the 120 degree oil temperature. The rest of the flight was fairly normal. The captain advised the flight attendants and passengers that we were landing in ZZZZ1 and it would be a normal landing. We planned a flaps 40 degree landing due to the 7;200 ft runway at 28 degrees and still having partial power in #1 for go-around. We did the descent approach checklists. Center and tower cleared us all the way down at our discretion and we made a normal landing. During the taxi in; we asked for crash fire rescue equipment personnel to view our #1 engine from a safe distance and report whether there was any visible damage. They reported only 'oil.' but our indications were normal. Except; during the portion right before we turned in to the gate area; we got a caution: 'oil filter bypass' indication. Passengers were deplaned; captain debriefed all of us on the plane immediately and we all discussed for a while. We handled it fine. But we could not get in radio communication with dispatch over ZZZZ1 at FL300-FL400. I don't think they realized the scope of the emergency; as they asked us if: 1) did we try increasing the affected engine's power back to normal? And 2) would we consider a diversion to ZZZZ2 -- which was 200 miles further than nearest suitable ZZZZ1? Nearest suitable airport is the best choice and I don't think that includes having a maintenance person on field.

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Original NASA ASRS Text

Title: B737NG flight crew report compressor stalls and engine failure at FL400 with diversion to nearest suitable airport. Uneventful landing ensues after rejecting company request to return to departure airport.

Narrative: Normal climb to cruise at FL400. Smooth and clear. At approximately over ZZZZ1 about XA50Z at FL400; #1 engine made loud bang (compressor stall); N1 dropped to about 60-70% and aircraft yawed. I disconnected the autopilot and autothrottles. Captain declared an emergency with Center. Engine indications were that it was still operating (rotating N1; N2; FF; etc.) -- although at lower thrust; with no vibration under 60%; but the oil temperature was about +/-123 degrees -- that seemed higher than normal. Right engine (#2 -- good engine) was only showing 80 degrees oil temperature. I asked for the QRH (Engine Limit/Surge Stall). No loss in oil quantity or other fluids; pressures. We decided that the engine did not have severe damage that we were aware of at the idle to approximately 50% setting. So we elected to leave it running and monitored it for declining trends. There were none. During this time Captain asked for descent to FL200; which we started a gradual descent and had 'Continuous' displayed on the FMS N1 limit page. We tried contacting Dispatch numerous times. Finally elected through ACARS and got response. We contacted the Flight Attendants; made a brief PA to passengers. By this time; we had already decided tht ZZZZ1 was our closest suitable airport (now 80 miles behind us). We were only 120;000 LBS (well below landing weight limit). ZZZZ1 had a 7;200 FT runway with CFR. By the time we asked Dispatch about their concurrence about diversion to ZZZZ1; they had started being able to hear us. They asked us to stand by for Maintenance Control. When they came back to us; they asked if we 'tried' using normal power again. We said no. Then; they asked if we'd considered going to ZZZZ2. Captain's response (shortened version) was 'No.' ZZZZ2 was 300 miles away. ZZZZ1 was only about 100 miles away at this point. ZZZZ3 was across the water 80 miles. We told ATC we were going to change our destination to ZZZZ1. Weather was clear and we obtained current conditions from ACARS and ATC -- and Dispatch concurred. We made a 180 degree turn back for ZZZZ1 and planned the descent with FMS and appropriate charts. The Captain and I discussed who should do the landing. He had the HUD; more experience; etc. So we decided that he would do the landing. During descent; the #1 engine was brought up to about 65% and we got vibration -- so we pulled it back to idle for the remainder of the flight. However; the only abnormal indication was the 120 degree oil temperature. The rest of the flight was fairly normal. The Captain advised the Flight Attendants and passengers that we were landing in ZZZZ1 and it would be a normal landing. We planned a flaps 40 degree landing due to the 7;200 FT runway at 28 degrees and still having partial power in #1 for go-around. We did the descent approach checklists. Center and Tower cleared us all the way down at our discretion and we made a normal landing. During the taxi in; we asked for CFR personnel to view our #1 engine from a safe distance and report whether there was any visible damage. They reported only 'oil.' But our indications were normal. Except; during the portion right before we turned in to the gate area; we got a caution: 'Oil Filter Bypass' indication. Passengers were deplaned; Captain debriefed all of us on the plane immediately and we all discussed for a while. We handled it fine. But we could not get in radio communication with Dispatch over ZZZZ1 at FL300-FL400. I don't think they realized the scope of the emergency; as they asked us if: 1) Did we try increasing the affected engine's power back to normal? And 2) would we consider a diversion to ZZZZ2 -- which was 200 miles further than nearest suitable ZZZZ1? Nearest suitable airport is the best choice and I don't think that includes having a maintenance person on field.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.