Definition
In aviation maintenance documentation, a primary division of a technical manual that groups related information about a specific system, component, or subject area. Chapters are typically numbered according to the ATA (Air Transport Association) Specification 100 system, which assigns standardized numbers to aircraft systems so that any technician can find the same type of information in the same chapter across different aircraft manuals.
Plain English
A main section of an aircraft manual that covers one system or topic. The numbering follows an industry-wide standard, so Chapter 32 always means landing gear, no matter which aircraft you are working on.
Context Anchor
Seen in aircraft maintenance manuals, parts catalogs, service instructions, and some training references when information is organized by aircraft system.
Derivation
From the Latin caput, meaning 'head.' A chapter was originally the 'heading' under which related material was grouped. The same idea carries into aviation manuals: each chapter is a heading covering one system or topic.
Why Pilots Care
Lets pilots and mechanics quickly find the exact procedures or data they need in large, complex documents without wasted time.
Intuition Check
Do not assume “chapter” only means a story-like section in a textbook. In aircraft documents, it often means a standardized manual section tied to a specific aircraft system or subject.
Example Sentence 1
The technician opened Chapter 27 of the maintenance manual to review the flight control rigging procedure.
Example Sentence 2
The mechanic found the fuel system diagram in ATA Chapter 28.