A B757-200 in climb at FL260 diverted due to unusual vibration in yoke, rudder pedals and floorboard...

Attributes
ACN	498904
Time
Date	200101
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl bound lower : 2500 msl bound upper : 26000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zma.artcc
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	climbout : intermediate altitude
Route In Use	enroute airway : a555.airway
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	498904
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical non adherence : published procedure non adherence : company policies other anomaly other
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : diverted to another airport
Consequence	other
Supplementary
Problem Areas	Aircraft Company Maintenance Human Performance
Primary Problem	Aircraft

Narrative:

We had departed ZZZ. On climb out, my first officer and I noticed an unusual vibration emanating from the yoke, rudder pedal, and floor boards. Flight attendant in the tail reported feeling a rumbling type vibration and noises coming from the floor and 4L door. They also said passenger could feel rumbling in their seats in the last rows of coach. I got a patch in to dispatch and maintenance control, and attempted to diagnose the problem as per technician's instructions, but could not pinpoint the problem. Technician suspected an access door or gear door open or possible rudder flutter. Technician recommended we land and I concurred. Mia ahead with thunderstorms en route and low ceilings and visibility. ZZZ was clear so we declared an emergency to get priority handling and returned to ZZZ. Normal landing was made and passenger were accommodated by services. Aircraft was taken OTS by maintenance. Callback conversation with reporter revealed the following information: the reporter stated the cause of the airframe vibration were loose fasteners on the mid cabin lavatory service panel door. The reporter said the door was closed, but the loose fasteners allowed the door to bulge into the airstream causing vibrations.

Original NASA ASRS Text

Title: A B757-200 IN CLB AT FL260 DIVERTED DUE TO UNUSUAL VIBRATION IN YOKE, RUDDER PEDALS AND FLOORBOARDS CAUSED BY LOOSE FASTENERS ON THE MID CABIN LAVATORY SVC PANEL DOOR.

Narrative: WE HAD DEPARTED ZZZ. ON CLBOUT, MY FO AND I NOTICED AN UNUSUAL VIBRATION EMANATING FROM THE YOKE, RUDDER PEDAL, AND FLOOR BOARDS. FLT ATTENDANT IN THE TAIL RPTED FEELING A RUMBLING TYPE VIBRATION AND NOISES COMING FROM THE FLOOR AND 4L DOOR. THEY ALSO SAID PAX COULD FEEL RUMBLING IN THEIR SEATS IN THE LAST ROWS OF COACH. I GOT A PATCH IN TO DISPATCH AND MAINT CTL, AND ATTEMPTED TO DIAGNOSE THE PROB AS PER TECHNICIAN'S INSTRUCTIONS, BUT COULD NOT PINPOINT THE PROB. TECHNICIAN SUSPECTED AN ACCESS DOOR OR GEAR DOOR OPEN OR POSSIBLE RUDDER FLUTTER. TECHNICIAN RECOMMENDED WE LAND AND I CONCURRED. MIA AHEAD WITH TSTMS ENRTE AND LOW CEILINGS AND VISIBILITY. ZZZ WAS CLR SO WE DECLARED AN EMER TO GET PRIORITY HANDLING AND RETURNED TO ZZZ. NORMAL LNDG WAS MADE AND PAX WERE ACCOMMODATED BY SVCS. ACFT WAS TAKEN OTS BY MAINT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE CAUSE OF THE AIRFRAME VIBRATION WERE LOOSE FASTENERS ON THE MID CABIN LAVATORY SVC PANEL DOOR. THE RPTR SAID THE DOOR WAS CLOSED, BUT THE LOOSE FASTENERS ALLOWED THE DOOR TO BULGE INTO THE AIRSTREAM CAUSING VIBRATIONS.

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.

A B757-200 in climb at FL260 diverted due to unusual vibration in yoke, rudder pedals and floorboards caused by loose fasteners on the mid cabin lavatory service panel door.