B737-400 flight crew has right engine vibration after takeoff; diverts for landing.

Attributes
ACN	705077
Time
Date	200607
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : yvr.airport
State Reference	BC
Altitude	agl bound upper : 3000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : cyvr.tower
Operator	common carrier : air carrier
Make Model Name	B737-400
Operating Under FAR Part	Part 121
Flight Phase	climbout : initial
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain
Qualification	pilot : atp
ASRS Report	705077
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : eng vibration indicator other flight crewa other flight crewb
Resolutory Action	flight crew : landed as precaution flight crew : diverted to another airport
Consequence	other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

Aircraft maintenance log had a write-up for 'possible bird strike; right side aircraft/wing/engine.' maintenance was called out by incoming crew; and verified by our crew. Maintenance by this time had the logbook; so I was briefed this by first officer. Due to security; we did not have face-to-face with inbound crew and had no further information. After maintenance arrived with logbook; I verified the logbook and asked maintenance technician what he found. He said he did find evidence of bird strike on #2 engine; on fan blade; but no indication of any damage or ingestion through compressor section or engine core. Verified discrepancy was addressed per maintenance procedures on log page. Taxied out for departure. On spool-up; engine indications were nominal initially and after passing 90 KTS noticed vibration meter on #2 was about 3 units and stable; and egt about 830 degrees and stable; but approximately 60 degrees above #1 engine level. After takeoff; we both noticed a very slight vibration and louder than normal sound. We continued to monitor engine instruments after climb power set and ran ato checklist followed by 'engine vibration' abnormal checklist. Engine vibration never exceeded about 3.3 units; but never dropped below approximately 2 units. Requested intermediate leveloff; and decided as crew we had possible damage related to bird strike write-up. Next contacted maintenance control and relayed information on engine parameters; previous write-up; and intention to proceed. Next contacted dispatch; and later relayed from maintenance control and dispatch concurrence to proceed. First officer remained PF while I coordination with maintenance control; dispatch; flight attendants and passenger. Autothrottles also turned off to see if idle thrust had any change to vibration level. Vibration remained at 2-3 units; informed dispatch of probable overweight landing; although we lowered gear and drag 30 mi north of sea for visual approach runway 34L. Landed with weight of 122300 pounds with sink rate below 100 FPM; very nice; smooth touchdown by first officer. Used aiii in hgs to monitor parameters.

Original NASA ASRS Text

Title: B737-400 FLT CREW HAS R ENG VIBRATION AFTER TKOF; DIVERTS FOR LNDG.

Narrative: ACFT MAINT LOG HAD A WRITE-UP FOR 'POSSIBLE BIRD STRIKE; R SIDE ACFT/WING/ENG.' MAINT WAS CALLED OUT BY INCOMING CREW; AND VERIFIED BY OUR CREW. MAINT BY THIS TIME HAD THE LOGBOOK; SO I WAS BRIEFED THIS BY FO. DUE TO SECURITY; WE DID NOT HAVE FACE-TO-FACE WITH INBOUND CREW AND HAD NO FURTHER INFO. AFTER MAINT ARRIVED WITH LOGBOOK; I VERIFIED THE LOGBOOK AND ASKED MAINT TECHNICIAN WHAT HE FOUND. HE SAID HE DID FIND EVIDENCE OF BIRD STRIKE ON #2 ENG; ON FAN BLADE; BUT NO INDICATION OF ANY DAMAGE OR INGESTION THROUGH COMPRESSOR SECTION OR ENG CORE. VERIFIED DISCREPANCY WAS ADDRESSED PER MAINT PROCS ON LOG PAGE. TAXIED OUT FOR DEP. ON SPOOL-UP; ENG INDICATIONS WERE NOMINAL INITIALLY AND AFTER PASSING 90 KTS NOTICED VIBRATION METER ON #2 WAS ABOUT 3 UNITS AND STABLE; AND EGT ABOUT 830 DEGS AND STABLE; BUT APPROX 60 DEGS ABOVE #1 ENG LEVEL. AFTER TKOF; WE BOTH NOTICED A VERY SLIGHT VIBRATION AND LOUDER THAN NORMAL SOUND. WE CONTINUED TO MONITOR ENG INSTS AFTER CLB PWR SET AND RAN ATO CHKLIST FOLLOWED BY 'ENG VIBRATION' ABNORMAL CHKLIST. ENG VIBRATION NEVER EXCEEDED ABOUT 3.3 UNITS; BUT NEVER DROPPED BELOW APPROX 2 UNITS. REQUESTED INTERMEDIATE LEVELOFF; AND DECIDED AS CREW WE HAD POSSIBLE DAMAGE RELATED TO BIRD STRIKE WRITE-UP. NEXT CONTACTED MAINT CTL AND RELAYED INFO ON ENG PARAMETERS; PREVIOUS WRITE-UP; AND INTENTION TO PROCEED. NEXT CONTACTED DISPATCH; AND LATER RELAYED FROM MAINT CTL AND DISPATCH CONCURRENCE TO PROCEED. FO REMAINED PF WHILE I COORD WITH MAINT CTL; DISPATCH; FLT ATTENDANTS AND PAX. AUTOTHROTTLES ALSO TURNED OFF TO SEE IF IDLE THRUST HAD ANY CHANGE TO VIBRATION LEVEL. VIBRATION REMAINED AT 2-3 UNITS; INFORMED DISPATCH OF PROBABLE OVERWT LNDG; ALTHOUGH WE LOWERED GEAR AND DRAG 30 MI N OF SEA FOR VISUAL APCH RWY 34L. LANDED WITH WT OF 122300 LBS WITH SINK RATE BELOW 100 FPM; VERY NICE; SMOOTH TOUCHDOWN BY FO. USED AIII IN HGS TO MONITOR PARAMETERS.

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.