Narrative:

Departure was uneventful until passing approximately 28;000. Airspeed during the climb was 320 KIAS due to overtaking traffic. Moderate airframe vibration of about 90-120 hertz was felt throughout the aircraft. Autopilot and auto-throttles were manually disconnected during the event. Decreasing both engine power and airspeed had little effect on the severity of the vibration. (All engine parameters were normal during the event and flight.) the event ceased about 45 seconds after it began. The flight attendants called the cockpit shortly after the event to report same. We leveled at FL330 and continued to troubleshoot the event. ECAM reports viewed via the FMGC maintenance reports; showed malfunctions on the ths and the right blue elevator servo. Dispatch was contacted through ACARS and then a phone patch. Maintenance control input was also requested. The connection to maintenance control was never established. The first officer and I decided with the unknown vibration and the flight control abnormality a prudent course of action would be a return to the nearest airport. (A divert airport was chosen due to known good weather [VMC and light winds]; long runway configuration; maintainer support and passenger support.) we informed the flight attendants of the divert and declared an emergency with ATC and received expedited vectors to the airport. At 10;000 ft and 25 NM from the airport we configured and performed a modified controllability check. Landing was uneventful. Crash fire rescue equipment inspected the aircraft prior to taxi to the gate. At arrival aircraft maintenance was debriefed on the event. Areas of concern: while the connection to dispatch went well; the follow on connection to maintenance control was unsuccessful. As such we; the flight crew; were on our own in making the decision to divert. This lack of communication with maintenance control needs to be corrected as soon as possible.

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Original NASA ASRS Text

Title: A320 flight crew climbing out of FL250 at 320 KTS experiences a very strong; fast rhythmic vibration; shaking the entire airplane and lasting for about 20-30 seconds. The vibration stops after the aircraft is slowed and the crew elects to divert to a suitable airport.

Narrative: Departure was uneventful until passing approximately 28;000. Airspeed during the climb was 320 KIAS due to overtaking traffic. Moderate airframe vibration of about 90-120 hertz was felt throughout the aircraft. Autopilot and auto-throttles were manually disconnected during the event. Decreasing both engine power and airspeed had little effect on the severity of the vibration. (All engine parameters were normal during the event and flight.) The event ceased about 45 seconds after it began. The flight attendants called the cockpit shortly after the event to report same. We leveled at FL330 and continued to troubleshoot the event. ECAM reports viewed via the FMGC maintenance reports; showed malfunctions on the THS and the right blue elevator servo. Dispatch was contacted through ACARS and then a phone patch. Maintenance Control input was also requested. The connection to Maintenance Control was never established. The First Officer and I decided with the unknown vibration and the flight control abnormality a prudent course of action would be a return to the nearest airport. (A divert airport was chosen due to known good weather [VMC and light winds]; long runway configuration; maintainer support and passenger support.) We informed the flight attendants of the divert and declared an emergency with ATC and received expedited vectors to the airport. At 10;000 FT and 25 NM from the airport we configured and performed a modified controllability check. Landing was uneventful. CFR inspected the aircraft prior to taxi to the gate. At arrival aircraft Maintenance was debriefed on the event. Areas of concern: While the connection to Dispatch went well; the follow on connection to Maintenance Control was unsuccessful. As such we; the flight crew; were on our own in making the decision to divert. This lack of communication with Maintenance Control needs to be corrected as soon as possible.

Data retrieved from NASA's ASRS site as of July 2013 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.