This article describes the “Technical Standard Order Authorization (TSOA)” in the form of a “Technical Standard Order (TSO)”, which is regulated by Federal Aviation Administration. TSO-C148 is a technical standard order written for aircraft mechanical fasteners. The Purpose, Applicability, and Requirements of TSO-C148 standard are described.
Introduction
FAA Title 14 of the Code of Federal Regulations (14 CFR) Part 21 – Certification Procedures for Products and Parts [1] as well as Federal Aviation Administration (FAA) Advisory Circulars AC 20-62E – Eligibility, Quality and Identification of Aeronautical Replacement Parts [2] and AC21-29B – Detecting and Reporting Suspected Unapproved Parts [3] provide information and guidance for use in determining the quality, eligibility and traceability of aeronautical parts and materials intended for installation on U.S. type-certificated products and articles, and to enable compliance with the applicable regulations.
The AC’s list a number of categories under which parts or materials may be approved, including but not limited to:
- Parts produced under Parts Manufacturer Approval (PMA)
- Parts produced during the Type Certificate (TC) application process
- Standard Parts conforming to an established U.S. Government or industry accepted specifications
- Technical Standard Order Authorization (TSOA)
- Etc. (several other categories of approvals)
This article describes the “Technical Standard Order Authorization” category of approval. This approval is issued in the form of a “Technical Standard Order”, in accordance with FAA order 2150.1 and AC21-46 [4].
A Technical Standard Order is a minimum performance standard, defined by the FAA, used to evaluate an article. An article can be material, part, component, process or appliance. Each TSO covers a certain type of article. The TSO provides a baseline standard that is intended to support compliance to airworthiness or operational requirements.
TSO-C148 – Aircraft Mechanical Fasteners
TSO-C1 8 is a performance standard for aircraft mechanical fasteners used by fastener manufacturers to define the performance of their proprietary designs, i.e. designs that are not covered by other performance standards such as MS, NAS, NASM, etc. [5].
Shown below is a section of TSO-C148, which shows the Purpose, Applicability and Requirements of this standard:
Many of the major manufacturers of aerospace fasteners have listed products in the TSO’s. An Index of FAA TSO articles can be found at:
https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgTSO.nsf/MainFrame?OpenFrameSet
The Index can be searched for articles by ‘TSO Holder’ or by ‘TSO Number’.
Some companies will specify their TSO Approval on their Sales Drawing. For example the Lisi/Monadnock sales drawing for a Stand Off Spacer 5300012 specifies the TSO approval.
TSO approval may also be specified on the Certificate of Compliance (C of C) provided by the manufacturer with each part shipment. If not sure if the part is TSO approved, contact the manufacturer.
Examples of Other TSO’s
- TSO-C149 – Aircraft Bearing
- TSO-C150 – Aircraft Seals
- TSO-C171 – Aircraft Clamps
Conclusion
TSO-C148 is one of the means FAA ensures that only approved Aircraft Mechanical Fasteners are used in the manufacture of United States Type Certificated Products.
Disclaimer
Avicast does not guarantee any results and does not incur any liability with regards to the information provided in this article. Avicast cannot and does not warrant the accuracy, correctness or completeness of the information and interpretation in this article.
Reference
[1] Federation Aviation Administration, Department of Transportation: Title 14 of the Code of Federal Regulations Part 21 – Certification Procedures for Products and Parts, available at http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&sid=fcefb2c2fc461b640c7f1cd13d037475&rgn=div5&view=text&node=14:1.0.1.3.9&idno=14
[2] Federal Aviation Administration, Department of Transportation: Advisory Circulars AC 20-62E – Eligibility, Quality and Identification of Aeronautical Replacement Parts, available at http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_60-22.pdf
[3] Federal Aviation Administration, Department of Transportation: AC21-29B – Detecting and Reporting Suspected Unapproved Parts, available at http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_21-29B_CHG2_[1].pdf
[4] Federal Aviation Administration, Department of Transportation: AC21-46, available at http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC-21-46.pdf
[5] Federal Aviation Administration, Department of Transportation: TSO-C148 – Aircraft Mechanical Fasteners, available at http://www.caa.gov.tw/BIG5/download/fsd/C148.pdf
[6] Lisi/Monadnock, Stand Off Spacer 5300012 Drawing, available at http://www.lisi-aerospace.com/_layouts/CentralDocConnector/DCConnector.aspx?id=7fa7f63a-5079-4a38-85c4-f028eae7a374&listId=Flanged%20Spacers&downloaded=MS-5300012-()&techDoc=false
