14 CFR · Part 21
14 CFR § 21.613
Duration.
(a)
A TSO authorization or letter of TSO design approval is effective until surrendered, withdrawn, or otherwise terminated by the FAA.
(b)
If a TSO is revised or canceled, the holder of an affected FAA letter of acceptance of a statement of conformance, TSO authorization, or letter of TSO design approval may continue to manufacture articles that meet the original TSO without obtaining a new acceptance, authorization, or approval but must comply with the requirements of this chapter.
Reflects the eCFR edition current as of September 29, 2026. Retrieved from ecfr.gov on October 16, 2026.
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