1. AECC Commercial Aircraft Engine Co, Ltd, Shanghai 200241, China
2. The Second Research Institute of Civil Aviation Administration of China,Chengdu 610041, China
3. Airworthiness Certification Center, Civil Aviation Administration of China,Beijing 100102,China
Carbon fiber/resin composites play an increasingly critical role in civil aviation engines. When composite components work as firewalls, a design assessment is required to demonstrate airworthiness compliance with Airworthiness Standards: Aircraft Engines(CCAR-33R2) 33-17 fire protection. To address the issue that lacking of tests study on fire-resistance of composites components and accumulate fundamental experimental data for fire protection design of composites in civilian aero-engine, the thickness-dependent flame resistance of thermosetting composites (carbon fiber/epoxy resin) and thermoplastic composites (carbon fiber/polyether ether ketone) was investigated by fire tests. Fire tests results show that both composites did not burn through after impingement of standard flame for 15 minutes, demonstrating good flame containment capacity. By measuring the temperature on the backward side, the changes in flame resistance with increasing layer thickness were revealed. A comparative analysis was conducted on the temperature difference on the backward face between the two composites and the influencing factors, which gives significant guidance for the aeronautical certification and validation of fire safety designs for composites, as well as for enhancing the overall fire safety of engines.