Definition
A small forward-facing tube mounted on the outside of an aircraft that captures the pressure of oncoming air during flight. This captured pressure, called ram or impact pressure, is fed to the airspeed indicator, where it is compared with static (still) air pressure to produce an airspeed reading.
Plain English
A little open-ended tube pointing into the wind on the outside of the airplane. As the airplane moves forward, air pushes into the tube, and the strength of that push is used to measure how fast the airplane is flying through the air.
Context Anchor
You see it during preflight inspection, airspeed system discussions, and situations such as slips where airflow may hit the airplane from an unusual angle.
Derivation
Named after Henri Pitot, a French engineer who in the 1700s invented this device to measure the speed of flowing water. The same idea — point a tube into the flow and measure the pressure — was later adapted to measure airspeed.
Why Pilots Care
Accurate pitot-tube pressure is essential for reliable airspeed indication; any blockage or damage produces false readings that can lead to loss of control, especially during slow-flight maneuvers such as intentional slips.
Analogy
Think of sticking your hand out of a moving car window. The faster the car goes, the harder the air pushes on your palm. The pitot tube does the same thing — it feels how hard the air is pushing and turns that into a speed reading.
Intuition Check
The pitot tube does not measure speed by spinning or by looking ahead. It senses air pressure caused by the airplane moving through the air.
Example Sentence 1
During preflight, the pilot removed the pitot tube cover and checked that the opening was clear of insects and debris.
Example Sentence 2
In the intentional slip the pilot watches the airspeed indicator fed by the pitot tube to keep the airplane just above stall speed while descending steeply toward the runway.