As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ANTI SKID SYSTEM TESTED ELECTRONICALLY OK, DUE TO A CHAFING LINE, LINE WAS REPLACED WHICH MANDATED A SYSTEM MECHANICALL CHECK. BOTH VALVES HAD FAILED. THE A/C WAS IN ON A HEAVY CHECK, USING THE MANUFACTER`S WORK CARDS, THERE IS NO CARD TO MECHANICALLY CHECK THIS SYSTEM. THE FAILED VALVE ALLOWED MAXIMUM BRAKE PRESSURE AT ALL TIMES. CANADIAN NORTH WILL BE DEVELOPING THEIR OWN WORK CARD FOR THIS TASK (TC 20090927001)