Definition
The friction-material blocks held inside a brake caliper that press against the rotating brake disc to slow or stop a wheel. When the pilot applies the brakes, hydraulic pressure forces the caliper pads against the disc, and the resulting friction converts the wheel's motion into heat.
Plain English
The two small pads inside the brake unit that squeeze against the spinning brake disc to slow the wheel down.
Context Anchor
Seen in landing gear and brake system descriptions, maintenance discussions, and inspections of aircraft wheel brakes.
Derivation
A caliper is a device with two arms or jaws that grip something from opposite sides. In a disc brake, the caliper straddles the disc and squeezes the pads against it from both sides — hence 'caliper pads.'
Why Pilots Care
Worn or contaminated pads reduce braking effectiveness and can cause longer landing rolls or loss of directional control on the ground.
Analogy
Works the same way as the disc brakes on a car or bicycle — two pads pinch a spinning disc to slow it down.
Intuition Check
Do not think of caliper pads as soft cushions. In this context, they are tough friction pieces designed to press hard against a rotating metal disc.
Example Sentence 1
During the preflight walk-around, the pilot checked the caliper pads for excessive wear before the first flight of the day.
Example Sentence 2
During the preflight inspection the mechanic checked the thickness of the caliper pads to confirm they still had enough material for safe braking.