Veritable Aviation

What Are Technical Standard Orders (TSO)?

After the first heavier-than-air powered flight conducted by the Wright brothers in 1903, aviation technology quickly began to develop through World War I and well beyond. Initially, aircraft technology and capabilities were very limited, and thus flight proved to be fairly dangerous. As aviation grew more commercial, industry leaders called for the government to create and maintain safety standards for the growth of the industry as a whole. With the establishment and governing of administrations such as the Federal Aviation Administration (FAA), airworthiness and safety of parts could be mandated through the use of standards such as the Technical Standard Order (TSO). Technical Standard Orders dictate a minimum performance standard that parts, materials, and appliances that are to be installed on civil aircraft must meet. In this blog, we will discuss Technical Standard Orders more in detail, exploring how they are approved and taken away, among other regulations and policies.

Whether the part that a manufacturer wants to create is a seat assembly or clip component, they must go through the FAA to have their parts be considered TSO parts. Approval for Technical Standard Orders work on a certification basis and require that the part is proven to meet, or exceed, airworthiness requirements of the aircraft model they are to be installed on. Airworthiness refers to an aircraft or component’s ability to maintain or produce safe flight, and rulesets and criteria to meet airworthiness are governed by the organizations that regulate produced parts in that location. When components are established as TSO parts, they are considered to have met set out, minimum performance requirements. However, this does not mean that the part may now be installed onto an aircraft, despite being considered a Technical Standard Part. For installation, a part must receive separate FAA Approval.

When a manufacturer outside of the United States wishes to produce Technical Standard Orders, they may apply for a letter of design approval. These letters are for components and parts that are produced in foreign countries, yet still meet the performance requirements that have been established for the particular item. The first requirement that a manufacturer must meet for approval is to be located within a country with which the United States has concluded a bilateral agreement pertaining to the submitted part. Bilateral agreements are agreements that have been made between the United States and a foreign country in regards to cooperation to meet airworthiness. If the country has an established bilateral agreement, the exporting Civil Aviation Authority (CAA) will then provide oversight for design and production of the part. To gain approval to produce TSO parts, the manufacturer needs to submit an application through the CAA, which will then be sent on to the FAA. If it is accepted, the FAA will provide a letter of TSO design approval for the component or part in question.

Besides approving and accepting parts as Technical Standard Orders, the FAA also holds the ability to cancel or withdraw their authorization. When the FAA has considered a Technical Standard Order to be inactive, the FAA will consider that TSO to be a “Canceled TSO”. This means that the part will no longer be able to be issued new TSO authorizations. Nevertheless, pre-existing TSO authorizations may still be produced following that approval. A “Withdrawal of a TSO authorization”, on the other hand, is used when the FAA withdraws their letter of authorization. When a Technical Standard Order authorization is withdrawn, the manufacturer is no longer approved to produce the specific component or part. Therefore, when TSOs are cancelled, the component may still be manufactured but will not receive new authorizations. When they are cancelled, the part may not be considered a TSO part when manufactured.

Information regarding the regulations and policies of Technical Standard Orders can be found on the website of the Federal Aviation Administration. Under Title 14 Code of Federal Regulations (14 CFR) Subpart O, Technical Standard Order Approval is discussed in length, establishing applicability and definitions, providing application instructions, information regarding quality systems, and much more information. The FAA also provides advisory circulars and other documents to help establish an understanding of the regulations and policies of TSO parts. When you are searching for new, used, or obsolete TSO parts for your aircraft or application, look no further than Veritable Aviation.

Veritable Aviation is owned and operated by ASAP Semiconductor, and we can help you find Seat Assy parts, Clip components, and TSO parts you need, new or obsolete. As a premier supplier of parts for the aerospace, civil aviation, and defense industries, we're always available and ready to help you find all the parts and equipment you need, 24/7x365. ASAP Semiconductor is an FAA AC 00-56B accredited and ISO 9001:2015 certified enterprise, and we are the only independent distributors with a no China sourcing policy. For a quick and competitive quote, email us at or call us at +1-503-374-0340.


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