Definition
An FAA Advisory Circular that provides acceptable methods, techniques, and practices for the inspection and repair of nonpressurized civil aircraft when no manufacturer's instructions are available. It is widely used as a reference for airframe and powerplant work, including weight and balance computations, structural repairs, and equipment installations.
Plain English
It is an FAA reference book that tells mechanics and inspectors the FAA-accepted ways to inspect and repair an aircraft when the manufacturer has not provided specific instructions.
Context Anchor
Seen in maintenance, inspection, repair, and weight-and-balance discussions, especially when a repair or equipment change could affect an aircraft’s empty weight or records.
Derivation
"AC" stands for Advisory Circular — an FAA document that gives guidance rather than regulation. The number "43.13-1" refers to 14 CFR Part 43, the federal regulation covering maintenance, preventive maintenance, rebuilding, and alteration. The circular supports that part of the regulations.
Why Pilots Care
Using the methods in this circular keeps the aircraft airworthy and prevents maintenance actions from creating unrecognized weight or balance problems.
Intuition Check
Do not read AC 43.13-1 as an aircraft part or a required checklist. It is an FAA guidance document used to support acceptable maintenance and repair practices.
Example Sentence 1
After the avionics installation, the mechanic recomputed the aircraft's empty weight and center of gravity using the procedures in AC 43.13-1.
Example Sentence 2
The weight and balance update followed the acceptable practices described in AC 43.13-1.