Study on Airworthiness Requirements of Composite Aircraft Structure for Transport Category Aircraft in FAA

This article focus on the introduction of composite structure characteristics and background of usage in civil aviation, also on airworthiness requirements in FAR 25 which include raw materials, manufacturing processes, structure static strength, fatigue property and damage tolerance. The building block approach, AGATE and NCAMP program are studied to improve the sharing of database furnished by material suppliers and to reduce cost in airworthiness certification. This article presents an analysis and testing methodology to support certification and maintenance of composite structures based on establishment of residual strength versus damage size relationships, determination of allowable ultimate load damage limits and limit load capability damage thresholds to insure that residual strength of composite structure is higher than the limit load strength. Other airworthiness considerations such as lightning protection, crashworthiness, fire protection and so on, are finally introduced for composite structure. A reference is provided to native composite structural airworthiness certification for transport category aircraft.