What was found
LIGHT TAIL VIBRATION IN CLIMB FL 210, 325 KTS. STOPPED WHEN SLOWED. AGAIN AT FL260 MACH .78 FOUND RUDDER INDICATION FLUCTUATING, IAW TSM 27-20-00-810-806-A. REPLACED IAW 31-55-34-00 0-001-A, TESTED NORMAL IAW 31-50-00-710-001-A. ACCOMPLISHED VIBRATION CHECK IAW TSM 05-50-810-801-A. RUDDER CHECKED NORMAL IAW TSM 27-20-00-810-802A, ELEVATOR CHECKED NORMAL IAW TSM 27-30-00-810-850-A.