Airworthiness directives are mandatory FAA rules that require you to correct a specific unsafe condition in your aircraft, engine, propeller, or appliance. Under 14 CFR Part 39, each one carries the force of federal regulation, and an aircraft that is out of compliance with even a single applicable directive is legally unairworthy and cannot be flown.1eCFR. 14 CFR 39.3 – Definition of Airworthiness Directives
What an Airworthiness Directive Does
The FAA issues an AD when it finds that an unsafe condition exists in a product and that the same condition is likely to appear in other units of the same type design.2eCFR. 14 CFR 39.5 – When Does FAA Issue Airworthiness Directives The causes vary: design flaws, manufacturing defects, or problems that only surface after years of service.
Each AD spells out the inspections you must perform, the conditions and limitations you must follow, and the corrective actions you must take.3eCFR. 14 CFR 39.11 – What Actions Do Airworthiness Directives Require ADs are published in the Federal Register as amendments to 14 CFR 39.13 and become part of the Code of Federal Regulations, though they are not reprinted in the annual edition.4eCFR. 14 CFR 39.13 – List of Airworthiness Directives When the unsafe condition demands immediate action, the FAA can issue an emergency AD delivered directly to known owners by fax, letter, or other means, effective only for those who receive it until a final rule follows in the Federal Register.5Federal Aviation Administration. Emergency Airworthiness Directives
Finding the ADs That Apply to Your Aircraft
The legal responsibility for keeping the aircraft airworthy, including compliance with every applicable AD, sits with the owner or operator.6eCFR. 14 CFR 91.403 – General You need to know which ADs apply to your airframe, your engine, your propeller, and every installed appliance.
The FAA’s Dynamic Regulatory System at drs.faa.gov is the official database. You can search by aircraft make, model, or AD number, and the FAA offers email subscription notifications for newly issued ADs. Your mechanic or inspection shop will typically cross-check ADs at annual inspection, but the legal obligation does not shift to them.7Federal Aviation Administration. Airworthiness Directives – Responsibilities
Reviewing the aircraft’s existing maintenance records is equally important. Those records should document every AD that has been complied with, the method used, and whether any recurring actions remain due. This is where problems hide when you buy a used aircraft. Incomplete AD compliance records can be costly to sort out after the sale.
Complying With an Airworthiness Directive
When You Have to Act
Every AD specifies its own compliance time. Some require action before the next flight. Others give you a window measured in hours of operation, calendar time, landing cycles, or a combination of these.8Federal Aviation Administration. AC 39-7D – Airworthiness Directives Read the compliance section of the AD carefully. The deadline is not negotiable without formal approval.
One-Time and Recurring Obligations
Some ADs require a single action. Inspect a component, replace a part, install a modification, and you are done. Recurring ADs mandate repetitive inspections or actions at set intervals. If an AD requires an inspection every 100 hours, that obligation continues for as long as you own and operate the aircraft. The AD may allow some flexibility to align the interval with other scheduled inspections, but any other change to the compliance time requires an approved alternative method.8Federal Aviation Administration. AC 39-7D – Airworthiness Directives
Who Can Do the Work
AD work must be performed by a certificated airframe and powerplant mechanic or an FAA-approved repair station. The exception is narrow: if the AD text itself says a pilot may accomplish the required action, a pilot can do it. AD compliance is not classified as preventive maintenance under 14 CFR Part 43 Appendix B, so owners holding only a pilot certificate cannot sign it off on their own authority.
Alternative Methods of Compliance
You do not always have to follow the exact procedure written into the AD. Anyone can propose an alternative method of compliance, or a different compliance timeline, as long as the proposal provides an equivalent level of safety.9eCFR. 14 CFR 39.19 – May I Address the Unsafe Condition in a Way Other Than That Set Out in the Airworthiness Directive This is called an AMOC.
Submit the proposal to your FAA principal inspector. If you don’t have one, send it to the manager of the FAA office identified in the AD.9eCFR. 14 CFR 39.19 – May I Address the Unsafe Condition in a Way Other Than That Set Out in the Airworthiness Directive The proposal must describe the specific actions you plan to take. The principal inspector may add comments and forward it to the responsible manager for a final decision. You cannot use the alternative until the manager approves it.
Each AD identifies the FAA Aircraft Certification Service office responsible for it, and the manager of that office has approval authority. In some cases the office delegates AMOC authority to designated engineering representatives or organization designation authorization holders, and the AD will say so. If an AD contains no AMOC provision at all, the AD itself has to be revised before any alternative method can be used.10Federal Aviation Administration. Airworthiness Directives – Alternative Methods of Compliance
Documenting Compliance
Recording AD compliance properly is a regulatory requirement, and weak records create real problems during inspections, audits, and aircraft sales.
Under 14 CFR 43.9, the person who performs the work must make a maintenance record entry that includes a description of the work (or a reference to approved data), the date it was completed, the name of the person who performed the work if different from the one approving it, and the signature and certificate number of the person approving return to service.11eCFR. 14 CFR 43.9 – Content, Form, and Disposition of Maintenance Records
Beyond the individual work entry, 14 CFR 91.417 requires you to maintain the current status of every applicable AD, including the AD number, revision date, and method of compliance. For recurring ADs, the records must also show when the next action is due.12GovInfo. 14 CFR 91.417 – Maintenance Records These AD status records travel with the airframe permanently and must be transferred to the buyer when you sell the aircraft. Advisory Circular 43-9C offers a suggested format for tracking AD compliance and describes acceptable methods for meeting the record-keeping requirements of Parts 43 and 91.13Federal Aviation Administration. AC 43-9C – Maintenance Records
What Happens If You Don’t Comply
The Aircraft Is Grounded
Operating a product that does not meet the requirements of an applicable AD violates 14 CFR 39.7.14eCFR. 14 CFR 39.7 – What Is the Legal Effect of Failing to Comply with an Airworthiness Directive Each time you fly or use the product while out of compliance, you commit a separate violation.15eCFR. 14 CFR 39.9 – What if I Operate an Aircraft or Use a Product That Does Not Meet the Requirements of an Airworthiness Directive An aircraft that is not in compliance with every applicable AD is considered unairworthy and cannot legally be flown.
Civil Penalties
The FAA can impose civil penalties under 49 U.S.C. ยง 46301. The base statutory cap for an individual or small business under the general penalty provision is $1,100 per violation, but violations of aviation safety regulations carry a higher cap of up to $10,000 per violation for individuals. For companies and other entities that are not individuals or small businesses, the maximum reaches $75,000 per violation.16Office of the Law Revision Counsel. 49 USC 46301 – Civil Penalties These statutory amounts are periodically adjusted for inflation. Because each flight while out of compliance counts as a separate violation, exposure adds up quickly.
Certificate Actions
The FAA can also act against pilot certificates, mechanic certificates, or repair station certificates. A pattern of operating an unairworthy aircraft, or of signing off AD compliance improperly, can lead to suspension or revocation.
Insurance
Aviation insurance policies commonly exclude unlawful use of the aircraft and operation without a valid airworthiness certificate in full force and effect. Flying with outstanding ADs can put you inside those exclusion clauses, and an insurer may deny a claim after an incident. Policy language varies, so read yours, but the risk of a coverage denial is real.
Who Pays for AD Compliance
This catches many new owners off guard. The FAA places no legal obligation on manufacturers to cover the cost of AD compliance. Financial responsibility falls entirely on the aircraft owner. Some manufacturers voluntarily absorb part or all of the cost, particularly for newer aircraft or where the AD addresses a clear manufacturing defect, but there is no industry-wide standard and each manufacturer handles it case by case. If you believe the manufacturer should share the cost, your options are to negotiate directly or, as a last resort, pursue the matter in court. For older aircraft or ADs that address wear-related issues, expect to pay the full bill yourself.
Moving a Grounded Aircraft for Repairs
If an outstanding AD grounds your aircraft but the repair has to happen at a distant facility, you are not necessarily stuck. Under 14 CFR 21.197, the FAA can issue a special flight permit, sometimes called a ferry permit, for an aircraft that does not currently meet airworthiness requirements but is capable of safe flight. Flying to a base where maintenance will be performed is one of the most common reasons these permits are issued.17eCFR. 14 CFR 21.197 – Special Flight Permits
Approval isn’t automatic. The FAA reviews the applicable ADs to determine whether the aircraft is eligible, and a certificated mechanic or repair station must inspect the aircraft before flight and document that inspection in the maintenance records. You will need to explain why the aircraft doesn’t meet airworthiness requirements and specify any restrictions during the ferry flight. The permit is issued by the Flight Standards District Office responsible for the departure area, or by an authorized Designated Airworthiness Representative, and comes with operating limitations that must be displayed in the aircraft alongside the airworthiness certificate, if applicable, and the permit itself.18Federal Aviation Administration. Special Flight Permits Not every AD situation qualifies. A cracked wing spar is a very different risk profile than an inspection of a fuel gauge sender.