Narrative:

Left engine oil filter bypass illuminated and we had to shut down the left engine in accordance with abnormal procedures. We coordination a descent and declared an emergency with center through a relay with an air carrier aircraft. For approximately 10 mins we couldn't contact our dispatcher through the radio or with ACARS (no communication). First officer flew aircraft while I coordination with ATC; the cabin; and finally our dispatcher. Our initial plan was to land at ZZZ1; but had to change our plan due to a pending thunderstorm at ZZZ1. ZZZ2 was also threatened by bad WX. We also ruled out ZZZ3 due to the short runways there. We decided to divert to ZZZ4 with the concurrence of our dispatcher. This allowed us to avoid thunderstorms and windshear. Minimal deviating of thunderstorms was also a result of this plan. We landed at ZZZ4 uneventful on runway 34L. First officer did great job of flying aircraft which allowed me time to focus on the coordination required to divert safely. I was certainly more comfortable in this scenario since I had seen a similar event in our simulator.

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Original NASA ASRS Text

Title: A B737-800 EXPERIENCED A L ENG OIL FILTER BYPASS WARNING AND FOLLOWING ABNORMAL PROCS SHUT THE ENG DOWN. AN EMER WAS DECLARED.

Narrative: L ENG OIL FILTER BYPASS ILLUMINATED AND WE HAD TO SHUT DOWN THE L ENG IN ACCORDANCE WITH ABNORMAL PROCS. WE COORD A DSCNT AND DECLARED AN EMER WITH CTR THROUGH A RELAY WITH AN ACR ACFT. FOR APPROX 10 MINS WE COULDN'T CONTACT OUR DISPATCHER THROUGH THE RADIO OR WITH ACARS (NO COM). FO FLEW ACFT WHILE I COORD WITH ATC; THE CABIN; AND FINALLY OUR DISPATCHER. OUR INITIAL PLAN WAS TO LAND AT ZZZ1; BUT HAD TO CHANGE OUR PLAN DUE TO A PENDING TSTM AT ZZZ1. ZZZ2 WAS ALSO THREATENED BY BAD WX. WE ALSO RULED OUT ZZZ3 DUE TO THE SHORT RWYS THERE. WE DECIDED TO DIVERT TO ZZZ4 WITH THE CONCURRENCE OF OUR DISPATCHER. THIS ALLOWED US TO AVOID TSTMS AND WINDSHEAR. MINIMAL DEVIATING OF TSTMS WAS ALSO A RESULT OF THIS PLAN. WE LANDED AT ZZZ4 UNEVENTFUL ON RWY 34L. FO DID GREAT JOB OF FLYING ACFT WHICH ALLOWED ME TIME TO FOCUS ON THE COORD REQUIRED TO DIVERT SAFELY. I WAS CERTAINLY MORE COMFORTABLE IN THIS SCENARIO SINCE I HAD SEEN A SIMILAR EVENT IN OUR SIMULATOR.

Data retrieved from NASA's ASRS site as of January 2009 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.