FAR 23.2540 — Icing Certification
FAR 23.2540 sets icing certification requirements for Part 23 airplanes: ice protection system safety and stall protection with the autopilot engaged.
FAR 23.2540 applies to manufacturers seeking certification of a Part 23 airplane for flight in icing conditions. The baseline icing environment is defined in Part 1 of Appendix C to Part 25, and an applicant may also request certification for additional atmospheric icing conditions beyond that baseline.
To earn that certification, the applicant must demonstrate, within the icing conditions requested:
- The ice protection system (anti-ice and de-ice equipment) provides for safe operation of the airplane throughout those conditions.
- The airplane design protects against stalling while the autopilot is engaged, since ice accretion can change stall characteristics and an inattentive pilot relying on autopilot could otherwise be surprised by a stall.
Why it matters operationally: as a pilot, knowing your airplane is certified under § 23.2540 tells you the ice protection equipment and autopilot stall behavior have been tested for the specific icing envelope listed in your AFM. Operating outside that envelope — for example, in freezing rain or large supercooled droplets not covered by the certification — is not approved.