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- Order 8900.1 , Volume 10, Chapter 11, Section 1
• MCPD Process - Order 8900.1, Volume 10, Chapter 11, Section 2