What was found
BRAKE SYSTEM: ON TAKEOFF ABOUT 80 KTS THE AIRCRAFT MADE AN UNCOMMANDED HARD RIGHT TURN. THERE WAS NO INDICATION OF ENGINE FAILURE, OR THRUST REVERSE DEPLOYMENT. THE RUNWAY WAS CONTAMINATED AND THE AIRCRAFT HAD BEEN DE-ICED SO THE ONLY THING THAT COMES TO MIND IS THAT A BRAKE LOCKED UP, BUT I HAVE NO IDEA OTHER THAN IT WAS ALL I COULD DO TO KEEP THE AIRPLANE ON THE RUNWAY WITH FULL LEFT RUDDER AND FULL LEFT BRAKE AS WELL AS USING POWER FROM THE RIGHT ENGINE. IT CAME VERY CLOSE TO GOING OFF THE RUNWAY