What was found
LOSS OF MULTIPLE SYS DURING CLIMB OUT. ACFT WAS LOADED DURING HEAVY RAIN, DURING LAST PART OF LOADING SECONDARY EXTERNAL POWER CYCLED OFF & ON RAPIDLY SEVERAL TIMES CAUSING TIMING OUT OF SEVERAL SYS. DURING CLIMB LOST VSPD GUIDANCE ON FLIGHT DIRECTOR FOLLOWING BY AUTO THROTTLE, AUTOPILOT. DURING THIS PERIOD WE EXPERIENCED AIRFRAME BUFFET ALL DURING THIS TIME ACFT WAS FLYING IN HEAVY RAIN & MODERATE TURBULENCE. EVENTUALLY SYS, INCLUDING AIRSPEED WHICH HAD BEEN UNRELIABLE READING LOW. ACCOMPLISHED AIRFRAME BUFFET INSPECTION, NO DEFECT NOTED. R & R LT AIMS CPM & STD. ACCOMPLISHED AUTO LAND GND TEST & ALL PASSED.