FAR 23.2235 — Structural Strength

FAR 23.2235 establishes the basic structural strength requirements that small airplanes certified under Part 23 must meet. The structure has to be strong enough to handle two distinct load categories:

• Limit loads — the maximum loads expected in normal service. The airframe must support these without:
  • Interfering with the safe operation of the airplane (controls, systems, and handling must remain functional), and
  • Causing detrimental permanent deformation (the structure can flex, but it must return to shape).
• Ultimate loads — typically 1.5× limit loads. The structure must support these without breaking, even though permanent deformation is acceptable at this level.

Why it matters operationally: As a pilot, this is the rule behind your airplane's published load factor limits (the G-limits in your POH). Staying within those limits keeps you in the limit-load envelope, where the airframe is guaranteed safe and undamaged. Exceeding them pushes you toward ultimate loads — and beyond that, structural failure.