What was found
DURING TAXI OUT FOR DEPARTURE, WE EXPERIENCE SOME BRIEF BRAKE CHATTER DURING OUR LAST TURN PRIOR TO THE RUNWAY. WHILE AWAITING TAKEOFF CLEARANCE, WE SET THE PARKING BRAKE AND RECEIVED AN AMBER BRK FAIL CAUTION. WE CALLED OPS AND MCC, THEN SHUT THE AIRCRAFT DOWN AND CALLED THE FBO FOR A TOW BACK TO THE RAMP. A GROUND RESET PROCEDURE WAS NOT ACCOMPLISHED BECAUSE THE ISSUE OCCURRED WELL AFTER START UP AND TAXI OUT. RESET BRAKES. OPS CHECK GOOD. IAW PHENOM 300 AMM 31-31-00