Narrative:

During climb out through FL260 the captain announced we had an oil filter bypass light illuminated on the #1 engine. I was flying and continued to do so; while also taking over ATC communications. The captain referenced the FM and accomplished the oil filter bypass checklist while I requested to leveloff at FL280 with ATC. While following the checklist we retarded the left throttle to extinguish the light. At idle after a few seconds the light went out. I set up the aircraft for the drift-down and requested a lower altitude with ATC. The checklist directed to land at the nearest suitable airport so I requested a present position hold with ATC about 60 NM north of ZZZ. The captain finished the checklist and ran the drift-down checklist while in the holding pattern. I declared an emergency with ATC and the captain attempted to contact dispatch. It took several frequency changes to get a frequency that we could communicate with dispatch on. We decided to divert to ZZZ with dispatch concurrence. The captain advised the flight attendants of our situation and asked them to do a cabin advisory. He also spoke to the passenger and let them know of our intentions. We set up for the approach in the holding pattern and reviewed the abnormal landing confign landing distance and briefed the flaps 15 degree approach and landing. We coordinated to have emergency vehicles standing by in ZZZ; after the approach descent checklist was done the captain took the airplane and landed uneventfully with the left engine at idle. We taxied to the gate and shut down normally. The station was well prepared and ready for our arrival.

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Original NASA ASRS Text

Title: B737 FLT CREW EXPERIENCES OIL FILTER BYPASS LIGHT CLIMBING OUT OF FL260 AND AFTER COMPLYING WITH PROCEDURES; RETURNS TO DEPARTURE ARPT.

Narrative: DURING CLBOUT THROUGH FL260 THE CAPT ANNOUNCED WE HAD AN OIL FILTER BYPASS LIGHT ILLUMINATED ON THE #1 ENG. I WAS FLYING AND CONTINUED TO DO SO; WHILE ALSO TAKING OVER ATC COMS. THE CAPT REFED THE FM AND ACCOMPLISHED THE OIL FILTER BYPASS CHKLIST WHILE I REQUESTED TO LEVELOFF AT FL280 WITH ATC. WHILE FOLLOWING THE CHKLIST WE RETARDED THE L THROTTLE TO EXTINGUISH THE LIGHT. AT IDLE AFTER A FEW SECONDS THE LIGHT WENT OUT. I SET UP THE ACFT FOR THE DRIFT-DOWN AND REQUESTED A LOWER ALT WITH ATC. THE CHKLIST DIRECTED TO LAND AT THE NEAREST SUITABLE ARPT SO I REQUESTED A PRESENT POS HOLD WITH ATC ABOUT 60 NM N OF ZZZ. THE CAPT FINISHED THE CHKLIST AND RAN THE DRIFT-DOWN CHKLIST WHILE IN THE HOLDING PATTERN. I DECLARED AN EMER WITH ATC AND THE CAPT ATTEMPTED TO CONTACT DISPATCH. IT TOOK SEVERAL FREQ CHANGES TO GET A FREQ THAT WE COULD COMMUNICATE WITH DISPATCH ON. WE DECIDED TO DIVERT TO ZZZ WITH DISPATCH CONCURRENCE. THE CAPT ADVISED THE FLT ATTENDANTS OF OUR SITUATION AND ASKED THEM TO DO A CABIN ADVISORY. HE ALSO SPOKE TO THE PAX AND LET THEM KNOW OF OUR INTENTIONS. WE SET UP FOR THE APCH IN THE HOLDING PATTERN AND REVIEWED THE ABNORMAL LNDG CONFIGN LNDG DISTANCE AND BRIEFED THE FLAPS 15 DEG APCH AND LNDG. WE COORDINATED TO HAVE EMER VEHICLES STANDING BY IN ZZZ; AFTER THE APCH DSCNT CHKLIST WAS DONE THE CAPT TOOK THE AIRPLANE AND LANDED UNEVENTFULLY WITH THE L ENG AT IDLE. WE TAXIED TO THE GATE AND SHUT DOWN NORMALLY. THE STATION WAS WELL PREPARED AND READY FOR OUR ARR.

Data retrieved from NASA's ASRS site as of May 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.