Can a dispatcher release an aircraft with an open Airworthiness Directive?

Only if the AD's compliance time has not yet expired for that specific aircraft — for example, if 200 flight hours remain before the AD is due and the flight is within that limit. If the compliance deadline has passed, the aircraft is legally unairworthy and cannot be dispatched under any circumstances until maintenance certifies compliance. The dispatcher must verify AD status through the maintenance tracking system and maintenance release before signing the dispatch authorization.

Can an MEL deferral be used to get around an Airworthiness Directive?

No. An MEL deferral and an AD are entirely separate regulatory instruments, and the MEL cannot override an AD. The MEL permits certain inoperative equipment to be deferred within defined operational limits, but it cannot authorize deferral of any item that an AD requires to be functional or compliant. Relief from an AD compliance requirement requires either an Alternative Method of Compliance (AMOC) approved in writing by the FAA, or a specific deferral provision written into the AD itself.

What happens if the FAA issues an Emergency Airworthiness Directive for an aircraft already in a dispatcher's schedule?

An Emergency AD can require compliance before the next flight, effectively grounding the affected aircraft immediately regardless of where it is in the network. The dispatcher must identify every tail number in the fleet covered by the AD's applicability, pull those aircraft from the schedule, coordinate with maintenance control to assess compliance status, and reroute or substitute aircraft as needed. The dispatcher may not release a covered aircraft until maintenance provides a written certification of compliance or confirms the aircraft is not within the AD's applicability.

Airworthiness Directives and How They Affect a Dispatchable Aircraft

An Airworthiness Directive (AD) is one of the most powerful regulatory tools the FAA possesses. When an unsafe condition is found to exist in an aircraft type, engine, propeller, or appliance — and that condition is likely to exist or develop in other products of the same design — the FAA issues an AD to mandate corrective action. Unlike a manufacturer's Service Bulletin, which is a recommendation, an AD carries the full force of federal law. For an aircraft dispatcher operating under 14 CFR Part 121, understanding ADs is not an abstract regulatory exercise; it is a day-to-day operational reality that directly determines whether a specific tail number may legally depart.

This article explains what ADs are, how they are structured, how compliance is tracked, and — critically — how an open or deferred AD affects a dispatcher's release decision. The dispatcher shares legal responsibility for the airworthiness of the flight with the pilot in command, making AD awareness an essential competency.

What Is an Airworthiness Directive?

ADs are issued under the authority of 49 U.S.C. § 44701 and are published as amendments to 14 CFR Part 39, which governs airworthiness standards for aircraft products. Each AD identifies the affected make, model, and serial-number range; describes the unsafe condition; and specifies what must be done and by when. The FAA publishes ADs in the Federal Register and makes them freely searchable through the FAA's AD database online.

ADs come in two broad categories. A Notice of Proposed Rulemaking (NPRM)-based AD follows the standard rulemaking process: a proposed rule is published, the public may comment, and a final rule is issued. An Emergency AD (or Immediately Adopted Rule) skips the comment period when the FAA determines an unsafe condition poses an immediate threat to safety. Emergency ADs may ground entire fleets on short notice and are particularly significant for dispatchers because they can arrive mid-schedule.

How ADs Are Structured

Every AD contains several standard elements that a dispatcher and maintenance team must understand together:

Applicability: Defines which aircraft, engines, or appliances are covered, often by manufacturer, model, and specific serial number ranges. An AD for a Boeing 737-800 may not apply to a 737-900ER even within the same airline fleet.
Unsafe Condition: A plain-language description of the hazard — for example, fatigue cracking in a specific structural frame, a faulty actuator that could cause uncommanded control surface movement, or a software anomaly in an avionics unit.
Required Actions: The specific maintenance task, inspection, repair, or modification that must be performed. This may reference a manufacturer's Service Bulletin as the approved method of compliance.
Compliance Time: The deadline by which action must be taken. Compliance times are expressed in flight hours, calendar time, cycles (pressurization cycles, landings), or a combination — for example, within 500 flight hours or 6 months, whichever occurs first.
Alternative Methods of Compliance (AMOC): Some ADs allow an operator or owner to apply to the FAA for approval of an alternative method of compliance if the standard method is impractical, provided it achieves an equivalent level of safety.

The Dispatcher's Legal Framework: 14 CFR 121.628 and AC 120-77

Under 14 CFR § 91.7(a), as incorporated into Part 121 operations, no certificate holder may operate or dispatch an aircraft unless it is airworthy — meaning it must comply with all applicable ADs and be in conformity with its type certificate. 14 CFR § 121.628 (Airworthiness release or aircraft log entry) separately requires an airworthiness release or log entry before operating an aircraft that has undergone maintenance, preventive maintenance, or alterations, and — together with the operator's operations specifications — establishes the framework under which the MEL program operates. The dispatcher's signature on a dispatch release is a legal certification that, to the best of the dispatcher's knowledge, the aircraft is airworthy for the intended operation. This shared authority model, sometimes called the dual release concept, means a dispatcher cannot simply assume maintenance has resolved every open item; the dispatcher has an affirmative duty to verify.

Advisory Circular 120-77 (Maintenance and Alteration Data) provides guidance on how certificate holders should manage and document airworthiness compliance, including AD tracking. AC 120-77 emphasizes that operators must have a system — typically a computerized maintenance tracking program — that identifies every AD applicable to each tail number in the fleet, the current compliance status, and the next due date. The dispatcher relies on this system, in concert with the maintenance release, to confirm that no AD compliance deadline has been exceeded at the time of departure.

How an Open AD Affects Dispatch

When an AD compliance deadline falls due before the next planned maintenance opportunity, or when a recurring AD inspection is overdue, the aircraft is legally unairworthy and may not be dispatched. There is no gray area: dispatching an aircraft with an expired AD compliance interval is a violation of 14 CFR Part 39 and 14 CFR § 91.7, potentially exposing both the dispatcher and the certificate holder to civil penalty and certificate action.

However, not every open AD means an immediate ground stop. The dispatcher and maintenance team must jointly consider:

Compliance time remaining: If 50 flight hours remain before an AD is due and the flight is 4 hours, the aircraft is fully legal for that flight — though the dispatch system should flag when the due date is approaching.
Terminating vs. recurring actions: A one-time modification (terminating action) removes the AD obligation permanently once completed. A recurring inspection AD will come due again after each interval and must be tracked continuously.
Emergency ADs with immediate compliance: Some emergency ADs require action before next flight. In this case the aircraft is grounded until maintenance certifies compliance, regardless of where it sits in the network.
AMOCs in place: If the FAA has approved an AMOC for a specific operator, that approval must be documented and available to the dispatcher; the AMOC itself becomes the compliance method.

ADs and the MEL/CDL Relationship

A common misconception is that a Minimum Equipment List (MEL) deferral can override an AD. It cannot. The MEL, authorized under 14 CFR § 121.628(c) in conjunction with the operator's operations specifications and developed in accordance with the master MEL approved by the FAA (per the framework described in FAA Order 8900.1, Volume 4), is a document that permits inoperative equipment deferrals within defined limits. However, the MEL may never authorize deferral of equipment that is required to be operational by an AD, unless that specific AD itself contains a deferral provision or the operator has obtained an AMOC. Similarly, a Configuration Deviation List (CDL) addresses missing external parts within approved limits — it does not provide relief from AD compliance. The dispatcher must treat AD compliance as a constraint that sits above the MEL/CDL layer in the airworthiness decision hierarchy.

Practical Dispatch Workflow

In day-to-day Part 121 operations, the dispatcher typically does not read each AD text in real time. Instead, the workflow relies on a layered system of controls:

Maintenance tracking system: The airline's computerized system flags upcoming and overdue ADs for each tail number automatically.
Maintenance release: Before each flight, maintenance personnel sign a release certifying the aircraft is airworthy and that no AD compliance is overdue. The dispatcher reviews and accepts this release as part of the dispatch authorization process.
Irregular operations awareness: When Emergency ADs are issued, airline dispatch and maintenance control centers receive notifications through subscription services and FAA channels. The dispatcher must be prepared to ground affected aircraft immediately, reroute, or substitute tail numbers.
Coordination with maintenance control: For any ambiguity — such as an AD that may or may not apply to a specific serial number — the dispatcher escalates to maintenance control and does not release the aircraft until the question is resolved in writing.

Key Numbers and Rules

ADs are regulatory requirements under 14 CFR Part 39 and have the same legal weight as any other FAA regulation.
14 CFR § 91.7, as applied to Part 121 operations, prohibits operation of an aircraft that is not airworthy, which expressly includes AD compliance; 14 CFR § 121.628 separately governs the airworthiness release and log entry requirements tied to maintenance actions.
Compliance times in ADs may be expressed in flight hours, calendar days, cycles, or combinations — all must be tracked simultaneously; the most restrictive limit governs.
An AMOC must be FAA-approved in writing before it may substitute for the standard AD compliance method.
Emergency ADs may require compliance before next flight, effectively grounding the aircraft with little or no advance notice.
Dispatching an aircraft with an expired AD compliance interval is a serious violation of 14 CFR Part 39 and 14 CFR § 91.7; while FAA enforcement does not require proof of intent, operators may still raise defenses such as reasonable reliance on an approved maintenance tracking system or on a maintenance certification.

Common Test Traps

MEL overrides an AD: False. The MEL cannot defer an AD-required item unless the AD itself or an approved AMOC specifically allows it. This is one of the most frequently tested misconceptions on the Aircraft Dispatcher Knowledge Test.
Service Bulletins vs. ADs: A manufacturer's Service Bulletin is advisory unless specifically incorporated by reference into an AD, at which point it becomes mandatory. Confusing the two is a common error.
Applicability assumptions: Assuming an AD applies fleet-wide when it only covers a specific serial number range, or vice versa, can result in either an unnecessary ground or an illegal dispatch. Always verify the exact applicability statement.
AMOC without approval: Performing alternative maintenance without a written, FAA-approved AMOC does not constitute AD compliance, even if the work is technically superior.
Emergency AD timing: Assuming an Emergency AD allows the same compliance window as a standard AD. Emergency ADs often require immediate action before next flight — check the compliance time clause carefully.