Definition
A self-adjusting mechanism inside a brake assembly that automatically takes up the slack as the brake linings or pads wear, keeping the running clearance between the linings and the brake disc within design limits without manual intervention.
Plain English
A built-in part of the brake that quietly tightens itself a little each time the brakes wear down, so the brake stays at the right gap on its own.
Context Anchor
Seen in aircraft brake inspection, servicing, and maintenance procedures, especially when checking brake wear and brake clearance.
Derivation
From 'automatic' (Greek 'automatos' — self-acting) and 'adjuster' (one that sets to a correct position). Together: a part that sets itself to the correct position without being told to.
Why Pilots Care
Without an automatic adjuster, brake pedal travel would grow as the linings wear, and braking response would feel softer and less predictable. The adjuster keeps brake feel consistent throughout the life of the linings.
Intuition Check
Do not read automatic adjuster as a general setting that the pilot changes automatically. In this context, it is a specific brake mechanism that keeps brake clearance correct as the brake wears.
Example Sentence 1
During the brake inspection, the technician verified that the automatic adjuster was holding the correct running clearance between the lining and the disc.
Example Sentence 2
Excessive brake pedal travel can indicate that the automatic adjuster is not functioning as designed.