FAR 21.7 — Continued Airworthiness Requirements

FAR 21.7 ties transport category airplane design approvals and production to the continued airworthiness and safety improvement standards in Part 26 of the FARs. It applies to large airplanes (think airliners), not the typical training aircraft you'll fly as a student — but it's a regulation a well-prepared pilot should recognize.

The rule has two parts:

• (a) Design approval holders and applicants: On or after December 10, 2007, anyone holding or applying for a design approval (such as a type certificate) for a transport category airplane must comply with the applicable continued airworthiness and safety improvement requirements in Part 26.
• (b) New production airplanes: For newly manufactured transport category airplanes built under FAA authority, the type certificate holder or licensee must meet the Part 26 requirements that apply to new production airplanes. This only applies when the FAA has jurisdiction over the organization doing final assembly.

Operationally, this is why the airliners you'll one day fly receive ongoing safety upgrades — fuel tank flammability protection, damage tolerance reviews, and similar improvements — long after their original certification.