Definition
Indicated airspeed (IAS) is the speed shown directly on the airspeed indicator in the cockpit, derived from the difference between ram air pressure (from the pitot tube) and static air pressure (from the static port). KIAS is simply that value expressed in knots. It is uncorrected for instrument error, position error, air density, or compressibility effects.
Plain English
It is the airspeed number you read straight off the airspeed gauge, in knots, with no corrections applied.
Context Anchor
Seen on the airspeed indicator, in aircraft operating handbooks, on checklists, and in discussions of climbs, approaches, stalls, and speed limits.
Derivation
‘Indicated’ comes from the Latin indicare, meaning ‘to point out’ or ‘to show.’ It literally means ‘what the instrument is showing you’ — not what is true, not what is corrected, just what the needle is pointing at. ‘KIAS’ packs three ideas together: K for knots, IAS for indicated airspeed.
Why Pilots Care
It determines when the airplane will stall, how much runway is needed for takeoff, and the safe speed ranges printed on the airspeed indicator arcs.
Grounding Statement
At higher altitude, the same KIAS can correspond to the airplane moving faster through the thin air than the indicator number alone might suggest.
Intuition Check
Indicated does not mean fully corrected or exact in every sense. Here it means the speed displayed by the airspeed indicator, in knots.
Example Sentence 1
Example Sentence 2
Before rotating, the pilot verified the indicated airspeed had reached the recommended takeoff value on the indicator.