14 CFR § 33.15 - Materials.

---
identifier: "/us/cfr/t14/s33.15"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "14 CFR § 33.15 - Materials."
title_number: 14
title_name: "Aeronautics and Space"
section_number: "33.15"
section_name: "Materials."
chapter_name: "FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION"
subchapter_number: "C"
subchapter_name: "AIRCRAFT"
part_number: "33"
part_name: "AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "49 U.S.C. 106(g), 40113, 44701, 44702, 44704."
regulatory_source: "Docket No. 3025, 29 FR 7453, June 10, 1964, unless otherwise noted."
cfr_part: "33"
---


# 33.15 Materials.

The suitability and durability of materials used in the engine must—

(a) Be established on the basis of experience or tests; and

(b) Conform to approved specifications (such as industry or military specifications) that ensure their having the strength and other properties assumed in the design data.

(Secs. 313(a), 601, and 603, 72 Stat. 759, 775, 49 U.S.C. 1354(a), 1421, and 1423; sec. 6(c), 49 U.S.C. 1655(c))

[Amdt. 33-8, 42 FR 15047, Mar. 17, 1977, as amended by Amdt. 33-10, 49 FR 6850, Feb. 23, 1984]