Narrative:

On feb/sat/04, I was sent to ZZZ to ferry an aircraft back to ZZZ1. A B737-200 series aircraft had been removed from service for in-flight vibration. The aircraft had been written up approximately 5 times in the previous 5 days for a pronounced vibration which usually occurred at or above 290 KIAS. As I recall, the aircraft had flown at least 2 times during that period with no write-ups concerning a vibration. I talked with the maintenance controller in ZZZ about the aircraft's history as I was concerned about an aircraft having any kind of vibration in-flight. He stated he had seen about 9 other instances of this type of vibration with B737-200 aircraft in his 15 or so yrs in his job. Each time the problem was caused by worn bushings in the elevator tabs. This is what was suspected in this aircraft. Over the previous 5 days, maintenance had accomplished the 'easy stuff' in their troubleshooting guide and it was now to the point where they were going to have to tear down the elevator and replace some parts. Our maintenance man assured me that with the bolt that holds the elevator in place, there was no way it could depart the aircraft due to this vibration. An air carrier mechanic was flying into ZZZ to sign off the maintenance ferry paperwork and I requested he join us on the flight to ZZZ1. I also had him do a thorough preflight walkaround with special emphasis on all flight control surfaces. We even deployed the flaps so he could check them more thoroughly. Through discussions with our dispatcher, our system manager of domestic flight operations, and our maintenance controller in ZZZ1, we deemed the aircraft to be flight worthy and agreed to fly the aircraft back to ZZZ1. Taking into consideration the consistency of the write-ups, the fact that no one had diverted due to the vibration, and that the aircraft had recently flown a few legs without any vibration write-up, we felt the aircraft could be safely flown to ZZZ1 at 280 KIAS so as to not get the vibration. The flight was uneventful, although we did get the vibration at a few points during the flight. It occurred at 257 KIAS and 262 KIAS at different points during descent. We also got the vibration at one point during climb out at 280 KIAS. Having the autoplt on or off did not make a difference. Callback conversation with reporter revealed the following information: the reporter stated the vibrations could be duplicated at several airspds with autoplt on or off. The reporter said the maintenance action taken and components replaced to correct the vibration is unknown. The reporter stated maintenance said the positive fix action would be reported to the crew.

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Original NASA ASRS Text

Title: A B737-200 WITH RPTED INFLT VIBRATION 5 TIMES IN 5 DAYS IS MAINT FERRIED TO A MAINT FACILITY. CAUSE UNKNOWN.

Narrative: ON FEB/SAT/04, I WAS SENT TO ZZZ TO FERRY AN ACFT BACK TO ZZZ1. A B737-200 SERIES ACFT HAD BEEN REMOVED FROM SVC FOR INFLT VIBRATION. THE ACFT HAD BEEN WRITTEN UP APPROX 5 TIMES IN THE PREVIOUS 5 DAYS FOR A PRONOUNCED VIBRATION WHICH USUALLY OCCURRED AT OR ABOVE 290 KIAS. AS I RECALL, THE ACFT HAD FLOWN AT LEAST 2 TIMES DURING THAT PERIOD WITH NO WRITE-UPS CONCERNING A VIBRATION. I TALKED WITH THE MAINT CTLR IN ZZZ ABOUT THE ACFT'S HISTORY AS I WAS CONCERNED ABOUT AN ACFT HAVING ANY KIND OF VIBRATION INFLT. HE STATED HE HAD SEEN ABOUT 9 OTHER INSTANCES OF THIS TYPE OF VIBRATION WITH B737-200 ACFT IN HIS 15 OR SO YRS IN HIS JOB. EACH TIME THE PROB WAS CAUSED BY WORN BUSHINGS IN THE ELEVATOR TABS. THIS IS WHAT WAS SUSPECTED IN THIS ACFT. OVER THE PREVIOUS 5 DAYS, MAINT HAD ACCOMPLISHED THE 'EASY STUFF' IN THEIR TROUBLESHOOTING GUIDE AND IT WAS NOW TO THE POINT WHERE THEY WERE GOING TO HAVE TO TEAR DOWN THE ELEVATOR AND REPLACE SOME PARTS. OUR MAINT MAN ASSURED ME THAT WITH THE BOLT THAT HOLDS THE ELEVATOR IN PLACE, THERE WAS NO WAY IT COULD DEPART THE ACFT DUE TO THIS VIBRATION. AN ACR MECH WAS FLYING INTO ZZZ TO SIGN OFF THE MAINT FERRY PAPERWORK AND I REQUESTED HE JOIN US ON THE FLT TO ZZZ1. I ALSO HAD HIM DO A THOROUGH PREFLT WALKAROUND WITH SPECIAL EMPHASIS ON ALL FLT CTL SURFACES. WE EVEN DEPLOYED THE FLAPS SO HE COULD CHK THEM MORE THOROUGHLY. THROUGH DISCUSSIONS WITH OUR DISPATCHER, OUR SYS MGR OF DOMESTIC FLT OPS, AND OUR MAINT CTLR IN ZZZ1, WE DEEMED THE ACFT TO BE FLT WORTHY AND AGREED TO FLY THE ACFT BACK TO ZZZ1. TAKING INTO CONSIDERATION THE CONSISTENCY OF THE WRITE-UPS, THE FACT THAT NO ONE HAD DIVERTED DUE TO THE VIBRATION, AND THAT THE ACFT HAD RECENTLY FLOWN A FEW LEGS WITHOUT ANY VIBRATION WRITE-UP, WE FELT THE ACFT COULD BE SAFELY FLOWN TO ZZZ1 AT 280 KIAS SO AS TO NOT GET THE VIBRATION. THE FLT WAS UNEVENTFUL, ALTHOUGH WE DID GET THE VIBRATION AT A FEW POINTS DURING THE FLT. IT OCCURRED AT 257 KIAS AND 262 KIAS AT DIFFERENT POINTS DURING DSCNT. WE ALSO GOT THE VIBRATION AT ONE POINT DURING CLBOUT AT 280 KIAS. HAVING THE AUTOPLT ON OR OFF DID NOT MAKE A DIFFERENCE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE VIBRATIONS COULD BE DUPLICATED AT SEVERAL AIRSPDS WITH AUTOPLT ON OR OFF. THE RPTR SAID THE MAINT ACTION TAKEN AND COMPONENTS REPLACED TO CORRECT THE VIBRATION IS UNKNOWN. THE RPTR STATED MAINT SAID THE POSITIVE FIX ACTION WOULD BE RPTED TO THE CREW.

Data retrieved from NASA's ASRS site as of July 2007 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.