# 14 C.F.R. § 27.307 (2026): Proof of structure

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/CFR_T14_P27_S27_307

## Section

- **Citation:** 14 C.F.R. § 27.307 (2026)
- **Heading:** Proof of structure
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** Title 14 CFR: Aeronautics and Space / Chapter I: FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION / Part 27: AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT / Subpart C: Strength Requirements / § 27.307: § 27.307   Proof of structure.

## Text

(a) Compliance with the strength and deformation requirements of this subpart must be shown for each critical loading condition accounting for the environment to which the structure will be exposed in operation. Structural analysis (static or fatigue) may be used only if the structure conforms to those structures for which experience has shown this method to be reliable. In other cases, substantiating load tests must be made.
(b) Proof of compliance with the strength requirements of this subpart must include—
(1) Dynamic and endurance tests of rotors, rotor drives, and rotor controls;
(2) Limit load tests of the control system, including control surfaces;
(3) Operation tests of the control system;
(4) Flight stress measurement tests;
(5) Landing gear drop tests; and
(6) Any additional test required for new or unusual design features.
(Secs. 604, 605, 72 Stat. 778, 49 U.S.C. 1424, 1425)
[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as amended by Amdt. 27-3, 33 FR 14105, Sept. 18, 1968; Amdt. 27-26, 55 FR 7999, Mar. 6, 1990]

## Nearby sections

- [14 C.F.R. § 27.301 (2026) § 27.301   Loads.](https://www.frixlaw.com/law-library/statutes/CFR_T14_P27_S27_301.md)
- [14 C.F.R. § 27.303 (2026) § 27.303   Factor of safety.](https://www.frixlaw.com/law-library/statutes/CFR_T14_P27_S27_303.md)
- [14 C.F.R. § 27.305 (2026) § 27.305   Strength and deformation.](https://www.frixlaw.com/law-library/statutes/CFR_T14_P27_S27_305.md)
- [14 C.F.R. § 27.307 (2026) § 27.307   Proof of structure.](https://www.frixlaw.com/law-library/statutes/CFR_T14_P27_S27_307.md)
- [14 C.F.R. § 27.309 (2026) § 27.309   Design limitations.](https://www.frixlaw.com/law-library/statutes/CFR_T14_P27_S27_309.md)
- [14 C.F.R. § 27.321 (2026) § 27.321   General.](https://www.frixlaw.com/law-library/statutes/CFR_T14_P27_S27_321.md)
- [14 C.F.R. § 27.337 (2026) § 27.337   Limit maneuvering load factor.](https://www.frixlaw.com/law-library/statutes/CFR_T14_P27_S27_337.md)
- [14 C.F.R. § 27.339 (2026) § 27.339   Resultant limit maneuvering loads.](https://www.frixlaw.com/law-library/statutes/CFR_T14_P27_S27_339.md)
- [14 C.F.R. § 27.341 (2026) § 27.341   Gust loads.](https://www.frixlaw.com/law-library/statutes/CFR_T14_P27_S27_341.md)
- [14 C.F.R. § 27.351 (2026) § 27.351   Yawing conditions.](https://www.frixlaw.com/law-library/statutes/CFR_T14_P27_S27_351.md)
- [14 C.F.R. § 27.361 (2026) § 27.361   Engine torque.](https://www.frixlaw.com/law-library/statutes/CFR_T14_P27_S27_361.md)
- [14 C.F.R. § 27.391 (2026) § 27.391   General.](https://www.frixlaw.com/law-library/statutes/CFR_T14_P27_S27_391.md)
- [14 C.F.R. § 27.395 (2026) § 27.395   Control system.](https://www.frixlaw.com/law-library/statutes/CFR_T14_P27_S27_395.md)
- [14 C.F.R. § 27.397 (2026) § 27.397   Limit pilot forces and torques.](https://www.frixlaw.com/law-library/statutes/CFR_T14_P27_S27_397.md)

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/CFR_T14_P27_S27_307. Check the current official text before relying on it. Not legal advice.