Definition
In the pitot-static system, a sealed compartment inside the airspeed indicator that receives ram air pressure from the pitot tube. The chamber contains a flexible diaphragm that expands as ram air pressure rises and contracts as it falls. This movement drives the linkage that turns the airspeed needle.
Plain English
A small sealed space inside the airspeed indicator where the air coming in from the pitot tube is captured. As the airplane flies faster, more air pressure builds up in this space, and that pressure is what makes the airspeed needle move.
Context Anchor
Seen in diagrams and explanations of the pitot-static system, especially around the pitot tube, airspeed indicator, and the lines that carry air pressure between them.
Derivation
Chamber comes from Latin camera, meaning a room or enclosed space. A pressure chamber is simply an enclosed space designed to hold air at a specific pressure so that pressure can be measured or used to drive something — in this case, the airspeed needle.
Why Pilots Care
It supplies the dynamic pressure data the airspeed indicator needs to display accurate speed information for takeoff, cruise, and landing decisions.
Grounding Statement
Picture moving air being guided into a small enclosed space, where its push is held long enough for the instrument to sense it.
Intuition Check
A pressure chamber here is not a large room or a cabin pressure area. It is a small enclosed part of the instrument system that holds air pressure for measurement.
Example Sentence 1
Ram air from the pitot tube enters the pressure chamber, where it pushes against a diaphragm to drive the airspeed needle.
Example Sentence 2
Blockage of the pressure chamber caused the airspeed indicator to read zero during the takeoff roll.