Short definition: IAS stands for Indicated Airspeed, which is the speed shown on the aircraft’s airspeed indicator based on pitot-static pressure readings.
Detailed explanation: Indicated Airspeed is the basic airspeed value pilots read directly from the instrument panel. It is derived from the difference between ram air pressure from the pitot tube and static air pressure, so it does not fully account for instrument error, position error, compressibility or changes in air density. For this reason, IAS is not the same as true airspeed or groundspeed. In normal operations, IAS is especially important because aircraft performance limits such as stall speeds, flap operating speeds and many other speed restrictions are referenced to it. In flight simulation, using IAS correctly helps with take-off, climb, approach and landing, because handling characteristics and safety margins are usually tied to indicated rather than actual speed over the ground.
Key considerations:
- IAS becomes less representative of actual speed through the air as altitude increases.
- A common mistake is confusing IAS with groundspeed when judging approach or climb performance.
- Using the correct IAS is essential for staying within operating limits and avoiding stalls or overspeed conditions.
Further Reading: Indicated Airspeed – Wikipedia
