Definition
The section of the Federal Aviation Regulations that sets out the maintenance, preventive maintenance, and alteration requirements for civil aircraft operated under part 91 (general operating and flight rules). It defines who is responsible for keeping an aircraft airworthy, what inspections are required, who may perform and approve maintenance, and what records must be kept.
Plain English
It is the part of the rulebook that tells private and general aviation aircraft owners and pilots what inspections their aircraft must have, who can do the work, and how it must be recorded.
Context Anchor
Seen in aircraft inspection and maintenance discussions, especially when learning the legal responsibilities of an aircraft owner or operator.
Derivation
CFR stands for Code of Federal Regulations, the official collection of U.S. federal rules. Title 14 covers Aeronautics and Space, part 91 covers general operating rules for civil aircraft, and a subpart is a labeled section within that part. Subpart E is the labeled section dealing specifically with maintenance.
Why Pilots Care
Compliance keeps the aircraft airworthy and legally operable; failure to follow these rules can ground the airplane or create safety risks.
Intuition Check
Do not read this as a description of an aircraft part. It is a legal reference: a numbered location in the FAA rules.
Example Sentence 1
Before signing for the rental, the pilot confirmed the aircraft's logbooks showed all inspections required by 14 CFR part 91, subpart E were current.
Example Sentence 2
During the pre-purchase review the mechanic pointed to 14 CFR part 91, subpart E to explain why the last annual inspection had to be documented.