The Major Change Process Document (MCPD) replaces the New Aircraft Process Guide (NAPG). The MCPD is designed to provide detailed guidance for a certificate holder-requested change of operations that requires validation tests and/or proving tests under Title 14 of the Code of Federal Regulations (14 CFR) part 121. (For example, a request from an existing 14 CFR part 121 certificate holder to add a new Make and Model (Type) of aircraft to its operations.)

MCPD Introduction – General Information (PDF) - Order 8900.1, Volume 10, Chapter 7, Section 1

MCPD Process (PDF) - Order 8900.1, Volume 10, Chapter 7, Section 2