Pitot tube

[2] It is widely used to determine the airspeed of aircraft;[3] the water speed of boats; and the flow velocity of liquids, air, and gases in industry.

The measured stagnation pressure cannot itself be used to determine the fluid flow velocity (airspeed in aviation) directly.

Several commercial airline incidents and accidents have been traced to a failure of the pitot-static system.

[7] In 2008 Air Caraïbes reported two incidents of pitot tube icing malfunctions on its A330s.

[8] Birgenair Flight 301 had a fatal pitot tube failure which investigators suspected was due to insects creating a nest inside the pitot tube; the prime suspect is the black and yellow mud dauber wasp.

Aeroperú Flight 603 had a fatal pitot-static system failure due to the cleaning crew leaving the static port blocked with tape.

The pitot tube can be inserted through a small hole in the duct with the pitot connected to a U-tube water gauge or some other differential pressure gauge for determining the flow velocity inside the ducted wind tunnel.

The fluid flow rate in a duct can then be estimated from: In aviation, airspeed is typically measured in knots.

Aircraft use pitot tubes to measure airspeed. This example, from an Airbus A380 , combines a pitot tube (right) with a static port and an angle-of-attack vane (left). Air-flow is right to left.
Types of pitot tubes
A pitot-static tube connected to a manometer
Pitot tube on Kamov Ka-26 helicopter
A Formula One car during testing with frames holding many pitot tubes
Location of pitot tubes on a Boeing 777
Pitot tube from an F/A-18
Weather instruments at Mount Washington Observatory . Pitot tube static anemometer is on the right.