A320 captain experienced a low frequency vibration below his feet at FL340 and elects to divert for ...

Narrative:

In cruise at FL340; [we] had a sudden low hum and vibration. There was a windshield pressure leak reported and fixed. First thought was leak was back. Started decent and contacted dispatch and got maintenance on line. Sound and vibration was below my feet. I felt it could have been a loose nose gear door; maintenance felt could be loose radar dome; or leaking window. No emergency declared; but decided ZZZ was best place to get looked at. Approximately 80 miles east of our divert airport at FL240 noise and vibration increased. A few minutes later it stopped and we got an avionics exhaust fan ECAM. [It] had small electric smell. Declared an emergency and picked up speed and landed at the airport. Had equipment standing by; but briefed tower and flight attendants that it was only precautionary. [We had a] normal landing and taxi to gate.

Original NASA ASRS Text

Title: A320 Captain experienced a low frequency vibration below his feet at FL340 and elects to divert for maintenance. During descent the vibration increases then stops abruptly; illuminating an avionics exhaust fan ECAM.

Narrative: In cruise at FL340; [we] had a sudden low hum and vibration. There was a windshield pressure leak reported and fixed. First thought was leak was back. Started decent and contacted Dispatch and got Maintenance on line. Sound and vibration was below my feet. I felt it could have been a loose nose gear door; Maintenance felt could be loose radar dome; or leaking window. No emergency declared; but decided ZZZ was best place to get looked at. Approximately 80 miles east of our divert airport at FL240 noise and vibration increased. A few minutes later it stopped and we got an Avionics exhaust fan ECAM. [It] had small electric smell. Declared an emergency and picked up speed and landed at the airport. Had equipment standing by; but briefed Tower and flight attendants that it was only precautionary. [We had a] normal landing and taxi to gate.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	975335
Time
Date	201110
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Component
Aircraft Component	Cooling Fan any cooling fan
Person 1
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 150 Flight Crew Total 26000 Flight Crew Type 9000
Events
Anomaly	Aircraft Equipment Problem Less Severe

A320 captain experienced a low frequency vibration below his feet at FL340 and elects to divert for maintenance. During descent the vibration increases then stops abruptly; illuminating an avionics exhaust fan ECAM.