A320 crew had an airframe vibration that seemed to be associated with higher airspeed.

Attributes
ACN	602752
Time
Date	200312
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : tpa.airport
State Reference	FL
Altitude	msl single value : 31000
Environment
Weather Elements	Turbulence
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zjx.artcc
Operator	common carrier : air carrier
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude climbout : vacating altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 20500 flight time type : 2500
ASRS Report	602752
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	other flight crewa other flight crewb
Resolutory Action	other
Consequence	other other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

During climb out of FL310 at 310 KIAS, we encountered a moment of moderate turbulence. Immediately after that there began a very strong rhythmic vibration that lasted for less than 2 mins. It was more noticeable in the rear of the aircraft, but was still significant throughout the aircraft. We were hand flying the aircraft, started slowing almost immediately and the vibration stopped very suddenly at about 285 KIAS. Speed was later increased to over 300 KIAS with no vibration. Continued to ord. Made logbook write-up and notified maintenance controller of occurrence.

Original NASA ASRS Text

Title: A320 CREW HAD AN AIRFRAME VIBRATION THAT SEEMED TO BE ASSOCIATED WITH HIGHER AIRSPD.

Narrative: DURING CLB OUT OF FL310 AT 310 KIAS, WE ENCOUNTERED A MOMENT OF MODERATE TURB. IMMEDIATELY AFTER THAT THERE BEGAN A VERY STRONG RHYTHMIC VIBRATION THAT LASTED FOR LESS THAN 2 MINS. IT WAS MORE NOTICEABLE IN THE REAR OF THE ACFT, BUT WAS STILL SIGNIFICANT THROUGHOUT THE ACFT. WE WERE HAND FLYING THE ACFT, STARTED SLOWING ALMOST IMMEDIATELY AND THE VIBRATION STOPPED VERY SUDDENLY AT ABOUT 285 KIAS. SPD WAS LATER INCREASED TO OVER 300 KIAS WITH NO VIBRATION. CONTINUED TO ORD. MADE LOGBOOK WRITE-UP AND NOTIFIED MAINT CTLR OF OCCURRENCE.

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.