ASF - Aircraft Deicing/Anti-icing Equipment

March 25, 2013

AOPA Air Safety Foundation

Aircraft Deicing and Anti-icing Equipment

FAA Safety Logo

The resources listed below are provided as additional information to the AOPA Air Safety Foundation's Aircraft Deicing and Anti-icing Equipment Safety Advisor. The links below provide information on icing accident statistics, weather flying strategies, certification of aircraft, and suggestions on how to tell if your aircraft is approved for flight in known icing conditions.

Safety Advisors ASF Safety Publications

FAA Advisory Circulars FAA Advisory Circulars

FAR/AIM Federal Aviation Regulations (FAR)
  • FAR 23 — Airworthiness Standards: Normal, Utility, Acrobatic, and Commuter Category Airplanes
  • FAR 91.527 — Operations in Icing Conditions

NASA Logo National Aeronautics and Space Administration (NASA)

Ice on wing Is my airplane approved for flight in icing conditions?

To determine if an airplane has flight in icing conditions certification:

Checkmark Check to make sure a placard that prohibits flight in icing, or similar wording such as "known icing", or "icing conditions," is not installed. This is one clue, but it should be backed up.
Checkmark Check the FAA approved Flight Manual (AFM), or the AFM supplement in the case of an airplane that has icing protection equipment installed in accordance with a STC, for wording on approval or prohibition of flight in icing conditions.
Checkmark If the airplane is new — or built after 1973 — check for references in the AFM or AFM supplement to "FAR 25, Appendix C" or similar. There may also be reference to the terms "continuous maximum" and "intermittent maximum" icing conditions. If the wording isn't there and ice protection equipment is installed, chances are the airplane has a non-hazard-type system.

Not all airplanes that are approved for flight in icing were certificated to the same standards. Aircraft certificated before the mid-1960's were considered "approved for flight in known icing" when the airplane was equipped with a complement of certified ice protection equipment spelled out in operational requirements, such as Bureau of Flight Standards Release No. 434. In the AFMs of these airplanes you will find a list of equipment required for flight in (known) icing. It's important to know if your airplane is in this category because the operating rules for icing distinguish these airplanes from ones that were certificated for icing by showing compliance to the later rule, 23.1419 Amendment 23-14, which became effective in 1973.

Airplane AFMs will provide a list of equipment that must be installed and must be operational before a flight into icing conditions is undertaken.

If none of the above answers the question satisfactorily, the airplane type certificate data sheet (TCDS) may provide a definitive answer under "Certification Basis". This heading is included in every TCDS under the "Data Pertinent to all Models" heading situated near the end of each TCDS. If there's a reference to 23.1419 at amendment 23-14 or higher, or to 25.1419, or to section 34 of Special Federal Aviation Regulation 23 (SFAR23) the airplane is approved for flight into icing conditions.

Manufacturers of airplanes equipped with approved-for-icing-condition systems today are complying with the latest standards, which require the performance, stability and controllability during flight in icing conditions to comply with the non-icing standards used for the basic airplane. In the TCDS for these airplanes you will find reference to 23.1419 at amendment 23-43 or higher.