What was found
A VIBRATION WAS FELT FROM APPROX MID CABIN GOING AFT. THE RT ELEVATOR INDICATION ON THE LOWER EICAS PAGE WAS INDICATING A FLUTTERING OF ABOUT 1 INDICATOR WIDTH. NO VIBRATION WAS FELT IN THE COLUMN OR YOKE. THE CTR AP WAS ENGAGED & REMAINED ENGAGED. CHANGES IN AIRSPEED & ALTITUDE DID NOT SEEM TO CONSISTENTLY AFFECT THE FLUTTERING IND ON EICAS. WHILE ACCOMPLISHING AIRFRAME VIBRATION CONDITIONAL INSPECTION IAW AMM 05-51-38, FOUND LT MOST AFT WING TO BODY FAIRING FASTENERS LOOSE. SECURED, ACCOMPLISHED ELEVATOR OPERATIONAL CHECK IAW AMM 27-31-00. NO DISCREPANCIES NOTED.