14 CFR § 33.25 - Accessory attachments.
---
identifier: "/us/cfr/t14/s33.25"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "14 CFR § 33.25 - Accessory attachments."
title_number: 14
title_name: "Aeronautics and Space"
section_number: "33.25"
section_name: "Accessory attachments."
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"
---
# 33.25 Accessory attachments.
The engine must operate properly with the accessory drive and mounting attachments loaded. Each engine accessory drive and mounting attachment must include provisions for sealing to prevent contamination of, or unacceptable leakage from, the engine interior. A drive and mounting attachment requiring lubrication for external drive splines, or coupling by engine oil, must include provisions for sealing to prevent unacceptable loss of oil and to prevent contamination from sources outside the chamber enclosing the drive connection. The design of the engine must allow for the examination, adjustment, or removal of each accessory required for engine operation.
[Amdt. 33-10, 49 FR 6851, Feb. 23, 1984]