scope:

PURPOSE. This order clarifies airworthiness certification requirements for conducting flight testing under § 21.191(b) of Title 14, Code of Federal Regulations (14 CFR) to show compliance with airworthiness regulations for approval of a design change. The procedures in this order apply only to U.S.-registered aircraft with a current standard airworthiness certificate and to be used by all Aircraft Certification Service (AIR) engineers, inspectors, and flight test pilots; all Flight Standards Service (AFS) inspectors; and any appropriately authorized AIR or AFS designees. The order focuses on three areas: (1) early communication with the applicant regarding show compliance requirements, (2) early Federal Aviation Administration (FAA) determination of whether flight testing to show compliance with airworthiness regulations and issuance of a special airworthiness certificate is required, and (3) the aviation safety inspector (ASI)'s or designee's role in reinstating the standard airworthiness certificate.