Definition
A flat or shaped metal plate used in an aircraft assembly to apply, transmit, or distribute clamping force against another component. In disc brake assemblies, the pressure plate is the moving plate that hydraulic pistons push against to squeeze the brake discs and stators together, producing the friction that slows the wheel.
Plain English
A strong metal plate that pushes against something else to hold it tight or, in a brake, to squeeze the parts that stop the wheel.
Context Anchor
Seen in aircraft wheel and brake maintenance, especially during brake inspection, repair, or replacement.
Derivation
From 'pressure' (Latin pressura, a pressing) and 'plate' (a flat piece of metal). The name describes its job directly: a plate whose purpose is to apply pressure.
Why Pilots Care
On brake-equipped aircraft, the condition of the pressure plate affects braking performance. A warped, worn, or unevenly loaded pressure plate can cause weak braking, brake drag, or uneven wear on the discs.
Intuition Check
Do not think of a pressure plate as a plate that creates pressure by itself. It is the part that receives force from the brake mechanism and passes that force into the brake parts.
Example Sentence 1
During the brake inspection, the technician checked the pressure plate for warping and uneven wear.
Example Sentence 2
When the pilot applied the brakes, hydraulic pressure pushed the pressure plate against the discs to slow the wheel.