How Do AD’s Effect your Aircraft Operation? By Ken Dufour, ASA, MAM, ATP, CFI

By Andrew Myers

September 9, 2020 Educational

An Airworthiness Directive (AD) is an important tool used by the Federal Aviation Administration (FAA) to communicate unsafe operating conditions relating to aircraft and aircraft equipment to aircraft owners. A primary safety function of the FAA is to require the correction of unsafe conditions found in an aircraft, aircraft engine, propeller, rotor, or appliance when such conditions exist or are likely to exist or develop in other products of the same design. These unsafe conditions can exist because of a design defect, maintenance, or other causes.

Title 14 of the Code of Federal Regulations (14 CFR) Part 39, Airworthiness Directives, defines the authority and responsibility of the Administrator in requiring the necessary corrective action to address unsafe conditions. ADs are used to notify aircraft owners and other interested persons of unsafe conditions and to specify the conditions under which the product may continue to be operated.

Definition of Airworthiness Directives

FAA's airworthiness directives are legally enforceable rules that apply to the following products: aircraft, aircraft engines, propellers, and appliances.

When does FAA issue airworthiness directives?

FAA issues an airworthiness directive addressing a product when we find that:

  1. An unsafe condition exists in the product; and
  2. The condition is likely to exist or develop in other products of the same type design.

What is the legal effect of failing to comply with an airworthiness directive?

Anyone who operates a product that does not meet the requirements of an applicable airworthiness directive violates this section.

What if I operate an aircraft or use a product that does not meet the requirements of an airworthiness directive?

If the requirements of an airworthiness directive have not been met, you violate §39.7 each time you operate the aircraft or use the product.

What actions do airworthiness directives require?

Airworthiness directives specify inspections you must carry out, conditions and limitations you must comply with, and any actions you must take to resolve an unsafe condition.

Are airworthiness directives part of the Code of Federal Regulations?

Yes, airworthiness directives are part of the Code of Federal Regulations, but they are not codified in the annual edition. FAA publishes airworthiness directives in full in the Federal Register as amendments to §39.13.

Note: For a complete list of citations to airworthiness directives published in the Federal Register, consult the following publications: For airworthiness directives published in the Federal Register since 2001, see the entries for 14 CFR 39.13 in the List of CFR Sections Affected, which appears in the “Finding Aids” section of the printed volume and at www.govinfo.gov. For citations to prior amendments, see the entries for 14 CFR 39.13 in the separate publications List of CFR Sections Affected, 1973-1985, List of CFR Sections Affected, 1964-1972, and List of CFR Sections Affected 1986-2000, and the entries for 14 CFR 507.10 in the List of Sections Affected, 1949-1963. See also the annual editions of the Federal Register Index for subject matter references and citations to FAA airworthiness directives.

Does an airworthiness directive apply if the product has been changed?

Yes, an airworthiness directive applies to each product identified in the airworthiness directive, even if an individual product has been changed by modifying, altering, or repairing it in the area addressed by the airworthiness directive.

What must I do if a change in a product affects my ability to accomplish the actions required in an airworthiness directive?

If a change in a product affects your ability to accomplish the actions required by the airworthiness directive in any way, you must request FAA approval of an alternative method of compliance. Unless you can show the change eliminated the unsafe condition, your request should include the specific actions that you propose to address the unsafe condition. Submit your request in the manner described in §39.19.

May I address the unsafe condition in a way other than that set out in the airworthiness directive?

Yes, anyone may propose to FAA an alternative method of compliance or a change in the compliance time if the proposal provides an acceptable level of safety. Unless FAA authorizes otherwise, send your proposal to your principal inspector. Include the specific actions you are proposing to address the unsafe condition. The principal inspector may add comments and will send your request to the manager of the office identified in the airworthiness directive (manager). You may send a copy to the manager at the same time you send it to the principal inspector. If you do not have a principal inspector, send your proposal directly to the manager. You may use the alternative you propose only if the manager approves it.

Where can I get information about FAA-approved alternative methods of compliance?

Each airworthiness directive identifies the office responsible for approving alternative methods of compliance. That office can provide information about alternatives it has already approved.

May I fly my aircraft to a repair facility to do the work required by an airworthiness directive?

Yes, the operations specifications giving some operators the authority to operate include a provision that allows them to fly their aircraft to a repair facility to do the work required by an airworthiness directive. If you do not have this authority, the local Flight Standards District Office of FAA may issue you a special flight permit unless the airworthiness directive states otherwise. To ensure aviation safety, the FAA may add special requirements for operating your aircraft to a place where the repairs or modifications can be accomplished. FAA may also decline to issue a special flight permit in particular cases if we determine you cannot move the aircraft safely.

How do I get a special flight permit?

Apply to FAA for a special flight permit following the procedures in 14 CFR 21.199.

What do I do if the airworthiness directive conflicts with the service document on which it is based?

In some cases, an airworthiness directive incorporates by reference a manufacturer's service document. In these cases, the service document becomes part of the airworthiness directive. In some cases, the directions in the service document may be modified by the airworthiness directive. If there is a conflict between the service document and the airworthiness directive, you must follow the requirements of the airworthiness directive.

Types of ADs issued

The FAA issues two categories of ADs:

• Normal Issue

• Emergency Issue

Standard AD Process

The standard AD process is to issue a Notice of Proposed Rulemaking (NPRM), followed by a Final Rule. After an unsafe condition is discovered, a proposed solution is published in the Federal Register 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 responds to the substantive comments or states there were no comments received.

Emergency AD

In some instances, the critical nature of an unsafe condition may warrant the immediate adoption of a rule without prior notice and solicitation of comments. An Emergency AD intends to correct an urgent safety of flight situation rapidly. This is an exception to the standard process. If 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.

Superseded AD

An AD is 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 a superseded AD.

Compliance with ADs

For purposes of compliance, ADs may be divided into two categories:

•Those of an emergency nature requiring immediate compliance before further flight, or

•Those of a less urgent nature requiring compliance within a relatively long period.

ADs are the “final rule,” and compliance is required unless a specific exemption is granted. Aircraft owners are responsible for ensuring compliance with all pertinent ADs. This includes those ADs that require recurrent or continuing action. For example, an AD may require a repetitive inspection every 50 hours of operation, meaning the particular inspection must be accomplished and recorded every 50 hours in service.

CAUTION: Aircraft owners are reminded that there is no provision to overfly the maximum hour requirement of an AD unless it is written explicitly into the AD

Amateur-Built Aircraft

For help in determining if an AD applies to your amateur-built aircraft, contact your local Flight Standards District Office (FSDO)

Summary of ADs

14 CFR Part 91, section 91.417, requires a record to be maintained that shows the current status of applicable ADs, including:

• Method of compliance;

• AD number and revision date;

• Date and time when due again, if recurring;

• certified mechanic’s signature;

• Type of certificate; and

•Certificate number of the repair station or mechanical performing the work

For ready reference, many aircraft owners keep a chronological listing of the pertinent ADs in the back of their aircraft and engine records. Generally, a summary of ADs contains all the valid ADs previously published. Figure 9-1is a sample form of a summary of ADs.

Obtaining ADs

Both AD categories (small and large aircraft) are published in biweekly supplements. All ADs are available on the FAA website at www.faa.gov. Advisory Circular (AC) 39-7 (as revised), Airworthiness Directives, provides additional guidance and information for aircraft owners and operators about their responsibilities for complying and recording ADs. For more information, contact the FAA Regulatory Support Division, Delegation, and Airworthiness Programs Branch (AIR-140). AIR-140 contact information is available in the FAA Contact Information appendix on pages A1–A2 of this handbook.

For more information on Aircraft Appraisals please contact VREF or Jason Zilberbrand at Jason@VREF.com

The above article is intended to provide an explanation and augment in pilots or technicians' language, topics to introduce aircraft owners and operators with supplemental information for our VREF subscribers. It is intended as a guide. Contact your nearest FAA Flight Standards District Office (FSDO) or FAA.gov for additional information. The data/information is obtained from numerous FAA and other industry sources. It is edited and believed to be accurate. VREF does not warrant the accuracy or the source material and assumes no responsibility to any person in connection with the use of this VREF article. Permission to reprint this article is granted, so far as the context of the information remains intact and appropriate credit is given to VREF Inc.