Definition
An electrical heating element built into the pitot tube that prevents or removes ice blockage of the tube's ram-air inlet and drain holes, keeping the airspeed indicator working in visible moisture or freezing conditions.
Plain English
A small heater inside the airspeed sensor that stops it from icing up. The pilot turns it on with a switch in the cockpit, usually before flying through clouds, rain, or cold air.
Context Anchor
Seen on cockpit switches and checklists, especially before flight in cold, wet conditions or when icing is possible.
Derivation
Named after Henri Pitot, an 18th-century French engineer who invented the tube used to measure fluid speed. 'Heat' is added because the tube must stay warm enough to keep ice from forming over its small openings.
Why Pilots Care
Blocked pitot tubes produce false airspeed indications that can trigger stalls, overspeeds, or loss of control, particularly when the pilot is already task-saturated.
Intuition Check
Pitot heat is not cabin heat or engine heat. It is heat for the pitot tube, the outside sensor used by the airspeed system.
Example Sentence 1
Before entering the clouds, she switched on the pitot heat to keep the airspeed indicator reading correctly.
Example Sentence 2
While managing multiple tasks in icing conditions, the pilot still remembered to verify pitot heat was on.