Chapter 12. Publications, Forms, & Records

Airworthiness Directives (ADs)

In accordance with part 39 of Title 14 of the Code of Federal Regulations, the FAA issues airworthiness directives in response to deficiencies and/or unsafe conditions found in aircraft, engines, propellers, or other aircraft parts. ADs, as they are known in the industry, require that the relevant problem must be corrected on all aircraft or aircraft parts using the same design. ADs are initiated as either proposed, corrective, or final (telegraphic) via the Federal Register. The Federal Register is the official daily publication of the United States Government. It is the printed method of informing the public of laws that are enacted or will be enacted. Electronic versions of ADs are available from the Federal Register and from the Regulatory and Guidance Library. You can search by manufacturer, model, or AD number. All ADs are “incorporated by reference" into part 39, and are considered final. ADs must be followed to remain in compliance with the FAA. Once an AD has been issued, a person/company is authorized to use the affected aircraft or part only if it has been corrected in accordance with the AD.

AD Content

Generally, ADs include:

  • A description of the unsafe condition.
  • The product to which the AD applies.
  • The required corrective action or operating limitations, or both.
  • The AD effective date.
  • A compliance time.
  • Where to go for more information.
  • Information on alternative methods of compliance with the requirements of the AD.

AD Number

ADs have a three-part number designator. The first part is the calendar year of issuance. The second part is the biweekly period of the year when the number is assigned. The third part is issued sequentially within each biweekly period.

Applicability and Compliance

The AD subject line specifically identifies the type certificate holder of the aircraft or products affected by the AD. The specific models affected, and any special considerations, such as specific installed part numbers or modifications, are listed in the AD applicability section. In order to find all applicable ADs for a specific product, you must search for ADs on the product, aircraft, engine(s), propeller, or any installed appliance. If there are multiple series under the aircraft or engine model, you must also search for ADs applicable to the model as well as the specific series of that model. The final determination of ADs applicable to a particular product can only be made by a thorough examination of the ADs and the product logbooks. No person may operate a product to which an AD applies, except in accordance with the requirements of the AD. Furthermore, the owner or operator of an aircraft is required by 14 CFR §91.403 to maintain the aircraft in compliance with all ADs. The AD specifies a compliance time that relates to the effective date of the AD. That compliance time determines when the actions are required.

Alternative Method of Compliance

Different approaches or techniques that are not specified in an AD can, after FAA approval, be used to correct an unsafe condition on an aircraft or aircraft product. Although the alternative was not known at the time the AD was issued, an alternative method may be acceptable to accomplish the intent of the AD. A compliance time that differs from the requirements of the AD can also be approved if the revised time period and approved alternative method provides an acceptable level of safety as the requirements of the AD.

Aircraft Listings

This document contains the specifications and data for certificated aircraft when the number of registered aircraft is 50 or fewer.

Aircraft Specifications

“Specifications" were originated during implementation of the Air Commerce Act of 1926. Specifications are FAA recordkeeping documents issued for both type certificated and non-type-certificated products which have been found eligible for U.S. airworthiness certification. Although they are no longer issued, specifications remain in effect and will be further amended. Specifications covering type-certificated products may be converted to type certificate data sheets at the option of the type certificate holder. However, to do so requires the type certificate holder to provide an equipment list. A specification is not part of a type certificate. Specifications are subdivided into five major groups as follows:

  • Group I — Type Certificate Aircraft, Engines and Propellers. Covering standard, restricted, and limited types issued for domestic, foreign, and military surplus products.
  • Group II — Aircraft, Engine, and Propeller Approvals. Covering domestic, foreign, and military surplus products constructed or modified between October 1, 1927, and August 22, 1938, all of which have met minimum airworthiness requirements without formal type certification. Such products are eligible for standard airworthiness certification as though they are type-certificated products.
  • Group III — Aircraft, Engine, and Propeller Approvals. Covering domestic products manufactured prior to October 1, 1927, foreign products manufactured prior to June 20, 1931, and certain military surplus engines and propellers all of which have met minimum airworthiness requirements of the Air commerce Act of 1926 and implementing Air Commerce Regulations without formal type certification. Such products are eligible for standard airworthiness certification as though they are type-certificated products.
  • Group IV — Engine Ratings. Covering unapproved engines rated for maximum power and speed only, their use being limited to specific aircraft with maximum gross weights less than 1,000 pounds. Such engines are not eligible for independent airworthiness certification. These ratings are no longer issued.
  • Group V — Engine Approvals. Covering military surplus engines meeting Civil Air Regulation (CAR) 13 design requirements without formal type certification. Such engines are eligible for airworthiness certification as though they are typecertificated engines.
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