Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 267
Troubleshooting; Confusion
Aircraft Equipment Problem Critical
Flight Crew Diverted; Flight Crew Inflight Shutdown; General Declared Emergency; General Maintenance Action
Aircraft
We were in cruise at 38;000 FT. About 100 miles east of MCI; I noticed a very small vibration almost sounding like a lavatory motor that runs longer than it should. The vibration went away after five seconds. There was no anomaly noted on the engine instruments. The same vibration came back a few more times and would go away in about five seconds with roughly five minutes elapsing between each occurrence. Before the last time the last vibration came back; I asked the First Officer to ask Center for lower because I didn't like that the vibration kept coming back even thought we tried speeds from .80 to .75 in .01 increments.Out of FL360 there was a much more noticeable vibration; which we actually felt through our seats. At this point; the left engine failed; the autopilot disengaged and various alarms illuminated on the engine instrument display screen. The Engine Failure and Driftdown checklists were accomplished after declaring an emergency with Center. A single engine overweight landing was accomplished at the nearest suitable airport.After an initial inspection by company Maintenance I was informed the left engine had seized to the point where you could not even turn the fan blades. A substantial amount of melted engine parts were also found in the tailpipe.
[No substantive additional information was included in the secondary narrative.]
A B737-700 flight crew declared an emergency and diverted to the nearest suitable airport when the left engine seized following several vibration cycles at cruise.