Federal Aviation Regulations Part 25 (FAR Part 25)

FAR Part 25 is the airworthiness standard for transport-category airplanes (over 12,500 lb max takeoff weight, or any turbojet). Every commercial airliner from a regional jet up is certified to it. The European equivalent is CS-25. The standard is 700-plus pages and prescriptive, covering structural integrity, performance, systems, and operational interfaces. Certification to Part 25 consumes 60 to 80 percent of an OEM's engineering effort on a new program. Compliance is shown through means of compliance: analysis, similarity, ground test, flight test, simulation, or a combination. Roles where this matters: Engineering, Certification, Flight Test, Quality.