As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AIRCRAFT WAS ON CLIMBOUT GOING THROUGH 6000 FEET WHEN ECS LIGHT CAME ON AND CABIN STARTED TO DE-PRESSURIZE. AIRCRAFT RETURNED TO RANKIN INLET WHERE MAINTENANCE DISCOVERED THAT TCA VALVE WAS STUCK IN THE FULL OPEN POSITION AND EXCESS HEAT TRIPPED THE SYSTEM OFF. TCA VALVE WAS REPLACED AND ECS SYSTEM CHECKED OK. (TC NR 20061204004)