Aircraft Lessons: What is an Airworthiness Directive

The Code of Federal Regulations (CFR) refers to the rules and regulations published in the Federal Register by the executive departments and agencies of the United States federal government. The CFR includes laws governing all aviation in the country, listed in Title 14 under Federal Aviation Regulations (FARs), as prescribed by the Federal Aviation Administration (FAA).

14 CFR 91.7 states that it is strictly prohibited for any person to operate an aircraft that is not in an airworthy condition. It is worth noting that airworthiness is not necessarily the same as flyable. In fact, many aircrafts owners might not even aware that their airships might be violating the law for not being “airworthy.”

What is Airworthiness?

The FAA provides a definition of airworthiness in FAR 3:5. Under this definition, airworthy means that “the aircraft conforms to its type design and is in a condition for safe operation.” Additionally, the regulation places responsibility on the pilot in command by stating, “the pilot in command of a civil aircraft is responsible for determining whether that aircraft is in condition for safe flight. The pilot in command shall discontinue the flight when unairworthy mechanical, electrical, or structural conditions occur.”

More information about the responsibility that lies with determining airworthiness is found in 14 CFR 91.407, stating that “no person may operate an aircraft that has undergone maintenance, preventative maintenance, rebuilding, or alteration unless: (1) It has been approved for return to service by a person authorized under 43.7 of this chapter; and (2) The maintenance record entry required by 43.9 or 43.11, as applicable, of this chapter, has been made.”

This section is important because a lot of aircraft owners and operators only rely on maintenance personnel to apply necessary repairs and carry out required inspections. The maintenances facilities are also the ones tasked to ensure all airworthiness directives are properly logged and signed. It is rare for the owners and operators to personally check if proper endorsements have been made to approve an aircraft for service. These endorsements are important because they also state if the aircraft is airworthy, provided that a 100-hour or annual inspection has taken place.

Regardless of the condition of the aircraft, the owner or operator should personally review the logged information after the aircraft comes back from maintenance. The logbooks are key in proving that an aircraft has been cleared for service since it should contain logs of the inspection, repairs, and airworthiness directives as required by the law.

Airworthiness Directives (ADs)

The airworthiness directives, or AD for short, help the FAA to keep aircraft owners, operators, pilots, and mechanics on the lookout for the latest maintenance issues. ADs are important enough to land its own section in the FARs, which is not usually included in commercial versions of the regulations.

There are different ADs that an aircraft might need to comply with before it is allowed to return to service. There are ADs that only require a one-time inspection or modification, while some others look for periodic inspections or part replacements. An AD can also apply to all aircraft within a specific brand or model, or it can only affect aircraft that fall into a certain serial number range. There are even ADs that only pertain to a determined set of components such as propellers, engines, landing gears, and accessories.

Passing an annual inspection is not enough to consider an aircraft airworthy in today’s AD-dependent standards. For instance, if an aircraft fails to secure any recurring ADs before its deadline, it will not be deemed airworthy even if it has already cleared its annual inspection.

Pilots aren’t normally required to check the aircraft’s AD compliance because it should be done by the owner or operator. However, if a pilot periodically flies the said aircraft, it is probably a good idea to check with the owner or operator if the necessary ADs have been complied with.
The AD compliance table is usually part of the aircraft’s maintenance records, so asking the mechanic about it is also a smart idea.

Registration and Re-Registration Requirements

If you are a first-time aircraft owner, your priority action should be to register your aircraft with the FAA. FAR 47.31 clearly states that “no one can operate an aircraft until it’s registered.” The same section includes information on how to apply for a certificate of registration. Once the FAA approves an aircraft’s permanent registration, the owner must keep the certificate in the aircraft at all times.

After an aircraft is successfully registered with the FAA, its owner becomes legally responsible for keeping it in an airworthy shape. FAR 91.403 attests to this, including requiring the owner to comply with all ADs issued by the FAA for the aircraft, its engine, and any relevant equipment. In addition, FAR 47.41 mandates the registered aircraft’s owner to report to the FAA any change in his (or her) permanent address, sale or export involving the aircraft, or any reason for ineligibility to register the aircraft.

Regulatory Requirements

According to FAR 91.7(a), “no person may operate a civil aircraft unless it is in an airworthy condition.” Subsection (b) of the same section states that an aircraft’s pilot-in-command should be fully responsible in determining if the aircraft is in a condition for safe flight. If the aircraft runs into any unairworthy electrical, structural, or mechanical issues, the pilot-in-command is required to discontinue the flight immediately.

Based on FAR 3:5(a), an aircraft is airworthy as long as it conforms to its type design and is in condition for safe operation. In this context, conformity to type is treated by the FAA to mean the same thing as being in brand new condition. If the aircraft was built in a factory, conforming to type means it must be in the same condition as when it was first taken out from the factory. The same rule applies to any alterations made to the aircraft; they should also be in the same condition as they were when a supplemental type certificate was issued to the owner.

The Airworthiness Concern Process

The Airworthiness Concern Process (ACP) is a cooperative information-sharing enterprise that aims to strengthen industry participation in the development of airworthiness issues. As an official part of FAA policy, the ACP requires the FAA to work with other industries and get them more involved in airworthiness concerns before creating and issuing an AD.

Prior to the ACP, the FAA had no direct connections to aircraft owners and operators, and as such leaked the necessary expertise in aircraft maintenance and operations to effectively create airworthiness regulations. Since the introduction of the ACP, more industries are taking part in sharing essential information to help analyze various aircraft-related affairs and think about the most economically viable, profitable and effective solutions.