Glossary

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A

AD

Airworthiness Directive: Legally enforceable regulations issued by the FAA in accordance with 14 CFR part 39 to correct an unsafe condition in a product.

E

EASA

European Union Aviation Safety Agency: The central regulatory body for civil aviation safety in the European Union.

P

PDF

Portable Document Format: You will need the Adobe Acrobat Reader to view this file.

PMA

Parts Manufacturing Approval: A combined design and production approval issued by the FAA to produce modification or replacement parts for sale and installation on type-certificated aircraft. It certifies that the aftermarket part meets FAA safety, quality, and airworthiness standards.

S

SAFO

Safety Alert for Operators: An FAA publication that provides critical safety-related information, often recommending specific actions for air carriers, operators, and training providers to address emerging hazards. It serves to educate and improve safety protocols.

SAIB

Special Airworthiness Information Bulletin: An information tool used by the FAA to alert, educate, and make non-regulatory recommendations to the aviation community regarding safety issues.

Service Bulletin

A document issued by aircraft, engine, or component manufacturers to communicate recommended modifications, inspections, or maintenance procedures for improved safety, reliability, or performance.

Service Letter

Also called a Service Information Letter (SIL), it is a non-mandatory, informational document issued by an aircraft or component manufacturer to recommend best practices, provide service updates, or enhance product reliability and safety.

Service Memorandum

A formal written communication used within organizations — such as airlines, regulatory bodies (FAA/EASA), or maintenance facilities — to convey official information, directives, or guidance.

STC

Supplemental Type Certificate: An official approval issued by aviation authorities (such as the FAA) for a major modification or alteration to an aircraft, engine, or component that was previously certified. It verifies that the modification meets safety standards and does not degrade the aircraft's original airworthiness.

T

TCCA

Transport Canada Civil Aviation: The national authority responsible for regulating and overseeing civil aviation safety in Canada.

TCDS

Type Certificate Data Sheet: An official document issued by a regulatory authority (like the FAA or EASA) that records the essential specifications, limitations, and requirements for a type-certified aircraft, engine, or propeller.