A319
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 240; Flight Crew Total 14000; Flight Crew Type 7000
Troubleshooting
Aircraft Equipment Problem Critical
Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Maintenance Action; General Declared Emergency
Aircraft
During the climbout; we experience a severe airframe vibration. We declared an in-flight emergency and return to departure airport for an uneventful landing.
The reporter stated that this aircraft had a history of vibration problems and that Maintenance decided the next step in trouble shooting was to replace both autopilot elevator servos. This was accomplished and the aircraft was returned to service with no subsequent vibration issues reported. At the time of onset the aircraft was climbing at 340 KTS and initial actions to quell the vibrations were to disconnect the autopilot and raise the nose to decrease airspeed to no avail. The flight attendants reported be unable to stand in the tail of the aircraft due to the up and down oscillations.
We were climbing to FL300 with weather radar on (weather in the area); when passing through FL200; we started to hear a very loud; vibrating; pounding noise in both the First Officer and Captain's headsets making communication with ATC difficult. Passing through FLl230; First Officer lost all abilities to hear ATC; (both with his headset and with his speaker volume switch on high) while I could just barely hear ATC on my headset. The First Officer could barely hear ATC through the Captain's speaker with volume turned full up due to noise. I asked ATC for a radio check and Center replied that he could hear us with a loud background noise. While First Officer was trying to reestablish communication; his headset fell off his head and then he stated to me that the deafening pounding sound was coming from inside the cockpit somewhere down by his right foot area. Shortly thereafter; the First Officer stated that he smells something; having just said that; I too could smell the odor. I told the First Officer that it smelled like an electrical wire burning. I told him to don his mask and I too then donned my mask. There was no visual smoke nor EICAS MESSAGES displayed. I assumed the pilot flying duties along with communications since the First Officer still was unable to hear on the radio. I declared an emergency and the need to return. The First Officer was able to notify the Purser that we were returning. While in the descent going through approximately FL200 the pounding noise stopped but the First Officer still was unable to hear on the radio but was able to talk to me on interphone through speaker. First Officer accomplished checklist and provided me with support while I flew/communicated with ATC. Somewhere around 9;000 FT; the First Officer was able to reestablish radio communications and resumed the rest of the pilot not flying duties. Approach and landing was normal and we were met by ARFF with no visual smoke/fire noted by them. There was never any smoke in the cockpit. Both First Officer and I then took off our masks and could not smell anything. We then proceeded back to the gate and canceled the emergency. After blocking in at the gate; we got a phone patch with Dispatch and Maintenance Control to inform them of what transpired. We also gave a verbal explanation to the mechanics who met the plane.
A319 flight crew reports a loud vibrating; pounding noise passing FL230. When ATC communications become nearly impossible the crew elects to declare an emergency and return to the departure airport. At FL200 in the descent the noise disappears and a normal landing ensues.