Definition
A flat, rigid metal plate inside a multiple-disc aircraft brake assembly that transmits the clamping force from the brake pistons onto the stack of rotating and stationary discs. When the pilot applies the brakes, hydraulic pressure pushes the pistons against the pressure plate, which in turn squeezes the disc stack together to produce the friction that slows the wheel.
Plain English
It is the heavy metal plate inside the brake that the pistons push on. That push is what clamps the brake discs together to stop the wheel from turning.
Context Anchor
Seen during aircraft wheel brake inspection, repair, and brake assembly discussions.
Derivation
The name describes the job: a plate that delivers pressure. Specifically, it takes the force from the brake pistons and presses it evenly across the disc stack.
Why Pilots Care
It directly affects braking effectiveness and stopping distance during landing and taxi operations.
Intuition Check
Do not read “pressure plate” as a part that measures pressure. In this brake context, it is a plate that receives pushing force and passes that force into the brake.
Example Sentence 1
During the brake inspection, the technician removed the pressure plate to check the condition of the discs behind it.
Example Sentence 2
During a brake inspection the mechanic checked the pressure plates for scoring that could reduce stopping power.