What was found
ENCOUNTERED A HUMMING AND VIBRATION THAT WE COULD FEEL IN THE FLOOR AT HIGHER SPEEDS. SPECIFICALLY BETWEEN 290 TO 315 KTS. THE HUMMING DID NOT SEEM TO BE RELATED TO A SPECIFIC ALTITUDE, BUT MORE TO AN AIRSPEED RANGE. THE AIRCRAFT DID NOT HANDLE ADVERSELY AND OTHERWISE OPERATED NORMALLY. THE POST FLIGHT INSPECTION DID NOT REVEAL ANY STRUCTURAL ISSUES. CORRECTIVE ACTION; PERFORMED AIRCRAFT NOISE AND VIBRATION INSPECTION. FOUND LH IB RAP SHROUD 1 VERY LOOSE IN MULTIPLE AREAS IN COMPARISON TO RH SIDE WHICH IS TIGHT AGAINST THE FLAP. REMOVED AND REPLACED LH IB FLAP SHROUD PANEL IAW PHENOM 300AMM 57-54-00/400.