What was found
IN LEVEL FLIGHT AT 11,000 FT, AUTOPILOT OFF, EXPERIENCED AN AIRFRAME VIBRATION AT APPROX 240 KTS. VIBRATION WAS FELT IN THE AIRFRAME, NOT & OF THE FLIGHT CONTROLS. FLIGHT CONTROL SYNOPTIC PAGE APPEARED NORMAL. VIBRATION DECREASE & WENT AWAY BELOW 230 KTS. LANDED AT 37,000 LBS GROSS. ON WALK AROUND, DISCOVERED THE LT UPPER HORIZONTAL STAB WIPER FARING CRACKED. FOUND HYD OIL COOLER FAN VIBRATING IN CASING. R & R HEAT EXCHANGER IAW AMM 29-11-42. SN OFF 1217 & SN ON 1323 JLC.