---
kind: "section"
citation: "14 C.F.R. § 21.613"
title: "14"
number: "21.613"
heading: "Duration."
url: "https://uscodex.org/cfr/14/21.613"
---

# §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- (a) A TSO authorization or letter of TSO design approval is effective until surrendered, withdrawn, or otherwise terminated by the FAA.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.

## Notes

### Source

Source: Docket No. FAA-2006-25877, Amdt. 21-92, 74 FR 53392, Oct. 16, 2009, unless otherwise noted.

### Authority

Authority: 42 U.S.C. 7572; 49 U.S.C. 106(f), 40105, 40113, 44701-44702, 44704, 44707, 44709, 44711, 44713, 44715, 45303.