What was found
YLW FLIGHT NR 2477: NR 1 HYD SYSTEM FAILED, LOST FLUID AND PRESSURE WITH ZERO FLUID QUANTITY. NR 1 HYD SYSTEM INTERMITTENTLY INDICATED 500-700 PSI PRESSURE BUT NO BRAKES WERE AVAILABLE ON LANDING. MAINTENANCE PERFORMED STEPS 5A, 5B AND 5C OF Q400 AMM 05-54-00 PG 604. REMOVED PRESSURE RETURN AND CARE DRAIN MANIFOLD FILTERS. INSPECTED AND FOUND METALLIC DEBRIS PARTICLES IN THE PRESSURE AND CARE DRAIN FILTERS. INSTALLED NEW HYD SYS NR 1 PRESSURE RETURN AND CASE DRAIN FILTER ELEMENTS IAW Q400 AMM 29-11-32 PGS 401-407. PERFORMED FLUSH OF THE NR 1 HYD SYSTEM IAW AMM TASK 29-10-00-617-802 PARA 1-4J (1)(A) THRU (AP). INSPECTED AND FOUND SOURCE OF HYD LEAK TO BE THE BOOTSTRAP PRESSURE LINE. REMOVED AND REPLACED