What was found
AIRCRFT NOT GROUNDED: OBSERVED FROM EXIT ROW 14 DURING FLAP DEPLOYMENT, SUSPECTED POS 3 AND 4 FLAPS RAPIDLY CYCLED +/- 10 INCHES WHERE INBD FLAPS AND OUTBOARD FLAPS MEET FLAP INDICATION NORMAL CAUSING ENOUGH VIBRATION TO BE NOTICED BY CREWMEMBER SITTING AT EXIT ROW. NOT APPARENT FROM COCKPIT. NOTE: RIGHT SIDE OF A/C. OPERATED FLAP SYSTEM PER AMM 27-50-00. NO ABNORMALITIES NOTED. NO DAMAGE TO FLAP SYSTEM NOTED. NO FAULTS NOTED. OPSCK OF FLAP SYSTEM OPERATION NORMAL.