Definition
A malfunction of the aircraft's pitot/static system in which blockage, leakage, or icing of the pitot tube, static ports, or associated plumbing causes the airspeed indicator, altimeter, and vertical speed indicator to display incorrect or unreliable readings.
Plain English
Something has gone wrong with the small openings on the outside of the aircraft that feed air pressure to the airspeed, altitude, and climb/descent instruments. When that happens, those instruments stop showing accurate values and may be misleading or stuck.
Context Anchor
Seen in instrument flying, abnormal instrument indications, and partial-panel decision-making when airspeed, altitude, or climb-and-descent information does not match what the airplane is actually doing.
Derivation
Pitot comes from Henri Pitot, the 18th-century French engineer who developed the tube that measures the pressure of moving air. Static refers to still, undisturbed air pressure outside the aircraft. Knowing this helps because the system depends on two different air pressures: one from air ramming into the pitot tube, and one from calm outside air at the static ports. A failure means one or both of those pressure sources is no longer being measured correctly.
Why Pilots Care
Unrecognized failures can lead to loss of control or spatial disorientation because pilots may react to false airspeed or altitude data.
Grounding Statement
The key idea is that the airplane may be flying normally while the instruments that depend on air pressure are not telling the truth.
Intuition Check
Do not assume a pitot/static system failure means the instruments go blank. The more dangerous case is that they may keep showing numbers that look believable but are wrong. Also, “static” does not mean radio noise here; it means the pressure of the outside air around the airplane.
Example Sentence 1
After climbing into icing conditions, the pilot suspected a pitot/static system failure when the airspeed indicator began rising even though power and pitch were unchanged.
Example Sentence 2
Training scenarios simulate pitot/static system failure so pilots learn to cross-check with backup instruments and power settings.