Narrative:

On climb out from ZZZ we noticed significant airframe bouncing/vibration while accelerating through 230 KTS. I was hand flying at the time and nothing abnormal could be felt through the control surfaces. Additionally; the flight attendants did not notice the condition. As we accelerated through 250 KTS and gained altitude; the bounce/vibration became less pronounced. However; the condition existed throughout the flight. The first officer and I discussed the flight manual section on vertical bounce and I discussed the situation with dispatch and maintenance control. We made the decision to continue to ZZZ1 as the condition appeared stable and dissipating. The bounce/vibration was slight at FL370 and reduced as we progressed. During descent the condition became more pronounced as we passed through FL300; but never reached the severity of the climb out vibration. The approach and landing were uneventful. Mechanics met the flight and we briefed them and the outbound flight crew. Callback conversation with reporter revealed the following information: this particular aircraft vertical bounce vibration was not a high frequency type of light chop that pilots experience from atmospheric conditions. In his carrier's flight manual there is a page that describes vertical bounce and causes; but those examples did not fit their experiences on this aircraft. Reporter also states the same aircraft was pulled out of service; inspected; but nothing physically found on the external surfaces that may have contributed to the vibration.

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Original NASA ASRS Text

Title: A B737-300 ACFT; DURING CLIMBOUT; EXPERIENCED SIGNIFICANT AIRFRAME BOUNCING/VIBRATION WHILE ACCELERATING THROUGH 230 KNOTS. SAME CONDITION DURING DESCENT.

Narrative: ON CLBOUT FROM ZZZ WE NOTICED SIGNIFICANT AIRFRAME BOUNCING/VIBRATION WHILE ACCELERATING THROUGH 230 KTS. I WAS HAND FLYING AT THE TIME AND NOTHING ABNORMAL COULD BE FELT THROUGH THE CTL SURFACES. ADDITIONALLY; THE FLT ATTENDANTS DID NOT NOTICE THE CONDITION. AS WE ACCELERATED THROUGH 250 KTS AND GAINED ALT; THE BOUNCE/VIBRATION BECAME LESS PRONOUNCED. HOWEVER; THE CONDITION EXISTED THROUGHOUT THE FLT. THE FO AND I DISCUSSED THE FLT MANUAL SECTION ON VERT BOUNCE AND I DISCUSSED THE SITUATION WITH DISPATCH AND MAINT CTL. WE MADE THE DECISION TO CONTINUE TO ZZZ1 AS THE CONDITION APPEARED STABLE AND DISSIPATING. THE BOUNCE/VIBRATION WAS SLIGHT AT FL370 AND REDUCED AS WE PROGRESSED. DURING DSCNT THE CONDITION BECAME MORE PRONOUNCED AS WE PASSED THROUGH FL300; BUT NEVER REACHED THE SEVERITY OF THE CLBOUT VIBRATION. THE APCH AND LNDG WERE UNEVENTFUL. MECHS MET THE FLT AND WE BRIEFED THEM AND THE OUTBOUND FLT CREW. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THIS PARTICULAR ACFT VERTICAL BOUNCE VIBRATION WAS NOT A HIGH FREQUENCY TYPE OF LIGHT CHOP THAT PILOTS EXPERIENCE FROM ATMOSPHERIC CONDITIONS. IN HIS CARRIER'S FLIGHT MANUAL THERE IS A PAGE THAT DESCRIBES VERTICAL BOUNCE AND CAUSES; BUT THOSE EXAMPLES DID NOT FIT THEIR EXPERIENCES ON THIS ACFT. REPORTER ALSO STATES THE SAME ACFT WAS PULLED OUT OF SERVICE; INSPECTED; BUT NOTHING PHYSICALLY FOUND ON THE EXTERNAL SURFACES THAT MAY HAVE CONTRIBUTED TO THE VIBRATION.

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.