Introduction to FAA Airworthiness Directives (ADs)

Overview by Sofema Online (SOL) www.sofemaonline.com

Airworthiness Directives (ADs) are legally enforceable rules issued by the FAA in accordance with 14 CFR part 39 to correct an unsafe condition in a product.

• 14 CFR part 39 defines a product as an aircraft, aircraft engine, propeller, or appliance

AD Development and Issuance

FAA Order 8040.1 defines FAA's authority and responsibility for the development and issuance of ADs.

Who first determines the need for an Airworthiness Directive (AD)?

•  The FAA Aircraft Certification Service has twelve Aircraft Certification Offices (ACO) within four Directorates

•  Each is responsible for the continued operational safety of products for which it has responsibility

•  Directorate responsibility is assigned by type of product: Transport Category Airplanes, Small Airplanes, Rotorcraft, or Engines and Propellers

Aviation Safety Engineers (ASEs) in the Directorate staff monitor assigned products to determine unsafe conditions and the need for ADs.

Additionally, the ASEs are responsible for monitoring products manufactured in other countries that are approved for use in the United States and initiating ADs for those products as necessary.

What are the AD functions of the four Directorates?

When an unsafe condition exists, the Directorate responsible for the product will draft, coordinate, and issue ADs based on information provided by an ACO or Directorate Standards Staff.

What is the responsibility of the owner of a Type Certificate?

The Type Certificate owner is responsible for:

•  Notifying the FAA when they become aware of any failure, malfunction, or defect in any product, part, process, or article manufactured by them (14 CFR 21.3)

•  Developing appropriate design changes to correct the unsafe condition(14 CFR 21.99(a))

•  Incorporating the corrective action in future production of the product to ensure the product is in condition for safe operation (14 CFR 21)

What is the responsibility of aircraft owners/operators?

•  Aircraft owners and operators are responsible for ensuring compliance with the requirements of all ADs that apply to their aircraft

•  Anyone who operates a product that does not meet the requirements of an applicable AD is in violation of 14 CFR 39.7

How do I determine the applicability of an AD?

•  The AD subject line specifically identifies the Type Certificate Holder of the product(s) affected by the AD

•  Specific model(s) affected, and any special considerations such as specific installed part number(s) or modification(s), are listed in the AD applicability section

How do I find all applicable ADs to a specific product?

In order to find all applicable ADs for a specific product, you must search for ADs on the product, for example, the 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.

Who has to comply with ADs?

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.

When do I have to comply with an AD?

The AD specifies a compliance time that relates to the effective date of the AD. That compliance time determines when the actions are required.

Airworthiness Directive Construct

Airworthiness Directives (ADs) consist of two parts, the preamble, and the rule.

The preamble provides the basis and purpose of the AD. The rule portion provides regulatory requirements for correcting unsafe conditions.

The FAA Aircraft Certification Directorates write ADs using the guidance provided in the AD Manual.

While the subject and affected products vary with each AD, the manual provides guidance regarding the content and format necessary in all ADs. The AD Manual is revised periodically for improvements and changes in AD formats and procedures.

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

Concerning Alternate Means of Compliance (AMOC)

Information on alternative methods of compliance with the requirements of the AD

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

Do all ADs include a corrective action?

No. Some ADs include limitations. However, each AD is intended to resolve the unsafe condition. For interim action ADs, actions that terminate the interim action are incorporated into an AD when they are determined.

When is an AD issued?

The FAA issues an AD addressing a product when we find an unsafe condition exists in a product; and,

The condition is likely to exist or develop in other products of the same type of design.

How are Airworthiness Directive (AD) documents tracked?

A decision to issue an AD begins when an Aviation Safety Engineer (ASE) in the accountable Aircraft Certification Office (ACO) or Directorate prepares an AD Worksheet.

The accountable Directorate then assigns a Directorate identifier to that worksheet. The Directorate identifier is the primary tracking number for AD actions involving a Notice of Proposed Rulemaking (NPRM) and for a Final Rule, request for comments (commonly referred to as an Immediately Adopted Rule).

All Final Rule ADs will be assigned an AD number and a 14 CFR part 39 amendment number when issued and sent to the Federal Register for publication.

Where are ADs published?

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 FAA Regulatory and Guidance Library (RGL).

How do I find and obtain copies of ADs?

The RGL contains all ADs. You can search for ADs by manufacturer, model, or AD number. You can download electronic copies of ADs from RGL to your computer. Also, you can subscribe to receive electronic copies of ADs by email:

What types of Airworthiness Directives (ADs) are issued?

We issue three types of ADs:

•     Notice of Proposed Rulemaking (NPRM), followed by a Final Rule
•     Final Rule; Request for Comments
•     Emergency ADs

What is considered the standard AD process?

The standard AD process is to issue an NPRM followed by a Final Rule. After an unsafe condition is discovered, a proposed solution is published as an NPRM, which solicits public comment on the proposed action

•  After the comment period closes, the final rule is prepared, taking into account all substantive comments received, with the rule perhaps being changed as warranted by the comments

•  The preamble to the final rule AD will provide a response to the substantive comments or state there were no comments received

What process can be used if an unsafe condition requires correction quickly?

Final Rule; Request for Comments. In certain cases, the critical nature of an unsafe condition may warrant the immediate adoption of a rule without prior notice and solicitation of comments.

•  This is an exception to the standard process. If the time by which the terminating action must be accomplished is too short to allow for public comment (that is, less than 60 days), then a finding of impracticability is justified for the terminating action, and it can be issued as an immediately adopted rule

•  The immediately adopted rule will be published in the Federal Register with a request for comments. The Final Rule AD may be changed later if substantive comments are received

When is an Emergency Airworthiness Directive (AD) issued?

An Emergency AD is issued when an unsafe condition exists that requires immediate action by an owner/operator. The intent of an Emergency AD is to rapidly correct an urgent safety of flight situation. For more information, see the Emergency AD page.

What is a superseded AD?

An AD is considered no longer in effect when it is superseded by a new AD. The superseding AD identifies the AD that is no longer in effect. There are no compliance requirements for an AD that has been superseded.

What is an Alternative Method of Compliance (AMOC) for an Airworthiness Directive (AD)?

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 may not have been known at the time the AD was issued, an alternative method could 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 provides an acceptable level of safety that is at least equivalent to that of the requirements of the AD

Why have provisions for the approval of an AMOC in an AD?

Provisions for an alternative method are desirable from an aircraft operator’s point of view and also eliminate the need for constant AD revisions when acceptable methods are developed for AD compliance.

•  If an AD does not contain provisions for approving an AMOC, the AD must be revised before compliance can be accomplished by any method other than what is stated in the AD

Who has the authority to approve an AMOC?

Each AD will state which office within the FAA Aircraft Certification Service is responsible for that AD.

•     The manager of the responsible office has the authority to approve an AMOC, including different compliance times, for the requirements of the specific AD
•     One of the FAA Aircraft Certification Offices will have responsibility for AMOC approvals for a product manufactured in the United States
•     For a product manufactured outside the United States, a Standards Staff branch office of one of the four FAA Aircraft Certification Directorates will generally be listed in the AD as having responsibility for AMOC approvals

Next Steps

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