14 CFR § 38.21 - Approval before compliance testing.

---
identifier: "/us/cfr/t14/s38.21"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "14 CFR § 38.21 - Approval before compliance testing."
title_number: 14
title_name: "Aeronautics and Space"
section_number: "38.21"
section_name: "Approval before compliance testing."
chapter_name: "FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION"
subchapter_number: "C"
subchapter_name: "AIRCRAFT"
part_number: "38"
part_name: "AIRPLANE FUEL EFFICIENCY CERTIFICATION"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 4321  7572; 49 U.S.C. 106(g), 40113, 44701-44702, 44704; 49 CFR 1.83(c)"
regulatory_source: "Docket No. FAA-2022-0241, Amdt. No. 21-107, 89 FR 12654, Feb. 16, 2024, unless otherwise noted."
cfr_part: "38"
---


# 38.21 Approval before compliance testing.

All procedures, weights, configurations, and other information or data that are used to establish a fuel efficiency level required by this part or in any appendix to this part (including any equivalent procedures) must be approved by the FAA prior to use in certification tests intended to demonstrate compliance with this part.