Unapproved aircraft part

Unapproved aircraft parts are aircraft parts not approved by civil aviation authorities for installation on type certified aircraft.

For example, the Federal Aviation Administration (FAA) defines a "standard part" as a part produced in accordance with government regulations, and it defines an "approved part" as a "standard part" that is in accordance with a specific set of criteria and specifications.^[1] The FAA standards for approved parts are in FAR 21.305. In the United States parts may be approved through a Parts Manufacturer Approval (PMA), with type certification procedures through approval from the agency's approval, through Technical Standard Orders (TSOs), and from conforming to recognized specifications from the aviation industry.^[2]

Parts manufactured without an aviation authority's approval are described as "unapproved"; they may be inferior counterfeits, have been used beyond their time limits, have been previously approved but not properly returned to service, be stolen, come with fraudulent labels, production overruns that were not sold with the agency's permission, and those that are untraceable.^[3] The parts are cheaper to buy and more profitable to sell than approved parts.^[4] Unapproved parts have been found on both civilian and military aircraft,^[5] and faulty ones have caused hundreds of incidents and crashes, some fatal, with about 24 crashes between 2010 and 2016.^[4]

Most industries are plagued by counterfeit and bogus parts of inferior quality,^[6] but the potential consequences of failure are far less serious.