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

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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.