---
kind: "unit"
title: "14"
title_heading: "Aeronautics and Space"
key: "chI/subchC/part21/subpartO"
level: "subpart"
label: "Subpart O"
heading: "Technical Standard Order Approvals"
release: "ecfr-current"
date: "2026-08-27"
url: "https://uscodex.org/cfr/14/chI-subchC-part21-subpartO"
sections_count: 15
---

# Subpart O — Technical Standard Order Approvals

Title 14 C.F.R. — Aeronautics and Space › Chapter I — Federal Aviation Administration, Department of Transportation › Subchapter C — Aircraft › Part 21 — Certification Procedures for Products and Articles

## Sections

- [§21.601. Applicability and definitions.](/cfr/14/21.601.md)
- [§21.603. Application.](/cfr/14/21.603.md)
- [§21.605. Organization.](/cfr/14/21.605.md)
- [§21.607. Quality system.](/cfr/14/21.607.md)
- [§21.608. Quality manual.](/cfr/14/21.608.md)
- [§21.609. Location of or change to manufacturing facilities.](/cfr/14/21.609.md)
- [§21.610. Inspections and tests.](/cfr/14/21.610.md)
- [§21.611. Issuance.](/cfr/14/21.611.md)
- [§21.613. Duration.](/cfr/14/21.613.md)
- [§21.614. Transferability.](/cfr/14/21.614.md)
- [§21.616. Responsibility of holder.](/cfr/14/21.616.md)
- [§21.618. Approval for deviation.](/cfr/14/21.618.md)
- [§21.619. Design changes.](/cfr/14/21.619.md)
- [§21.620. Changes in quality system.](/cfr/14/21.620.md)
- [§21.621. Issue of letters of TSO design approval: Import articles.](/cfr/14/21.621.md)