What was found
THE AIRCRAFT NOSED OVER ON LANDING CAUSED BY BOTH BRAKES BEING LOCKED ON TOUCHDOWN. PRIOR TO LANDING (SHORT FINAL) THE PILOT HAD TO USE FULL RUDDER DEFLECTION. WHEN THE AIRCRAFT TOUCHED DOWN THE AIRPLANE NOSED OVER. THE BRAKES WERE FOUND LOCKED, WHEN FULL RUDDER TRAVEL USED, THE LOCKPLATE CONTACTS THE FIREWALL AND LOCKS THE BRAKES. SUBMITTER STATED THIS IS A KNOWN CONDITION, BUT NO AD HAS BEEN ISSUED.