What was found
SEA - RIGHT BLEED DUCT WARNING MESSAGE AT FL 390. BOTH BLEEDS CLOSED. LOST CABIN PRESSURE. PASSENGER O2 MASKS DEPLOYED. NOTICED A BURNING ODOR IN CABIN ON DESCENT. LANDING UNEVENTFUL. REMOVED AND REPLACED CROSSOVER DUCT IAW CRJ 700 AMM 36-19-09-000-801-A04 AND 36-19-09-400-801-A04. OPERATIONAL CHECK LEAK CHECK OF BLEED AIR DETECTION LOOPS CHECKS GOOD. REMOVED AND REPLACED USED O2 GENERATORS IAW AMM TASKS 35-21-03-000-801-A01 AND 35-21-03-400-801-A01. OPERATIONAL TEST OF THE PAX O2 MANUAL DEPLOYMENT SYSTEM (ENTIRE SHIP SET) TEST GOOD IAW AMM TASK 35-20-00-710-803-A01. ACFT OK FOR CONTINUED SERVICE.