14 CFR § 31.21 - Loads.

---
identifier: "/us/cfr/t14/s31.21"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "14 CFR § 31.21 - Loads."
title_number: 14
title_name: "Aeronautics and Space"
section_number: "31.21"
section_name: "Loads."
chapter_name: "FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION"
subchapter_number: "C"
subchapter_name: "AIRCRAFT"
part_number: "31"
part_name: "AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS"
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. 1437, 29 FR 8258, July 1, 1964, as amended by Amdt. 31-1, 29 FR 14563, Oct. 24, 1964, unless otherwise noted."
cfr_part: "31"
---


# 31.21 Loads.

Strength requirements are specified in terms of limit loads, that are the maximum load to be expected in service, and ultimate loads, that are limit loads multiplied by prescribed factors of safety. Unless otherwise specified, all prescribed loads are limit loads.