What is indicated airspeed (IAS)?

Indicated airspeed (IAS) is defined as the speed shown on the airspeed indicator, which is influenced by dynamic air pressure as the aircraft moves through the air. This measurement is crucial because it directly reflects the aircraft's performance, including lift, drag, and fuel efficiency, relative to the surrounding air. IAS is essential for pilots as it provides them with real-time data necessary for safe flying, allowing them to manage the aircraft's speed appropriately in various flight modes such as takeoff, cruising, and landing.

While planning the speed for flight is an important aspect of operational procedures, indicated airspeed specifically refers to the reading on the airspeed gauge rather than a predetermined speed or an operational target. Similarly, although a certain speed is beneficial for executing maneuvers, IAS itself is not defined by the maneuvering capabilities of the aircraft. Additionally, regulations regarding maximum speeds do not pertain to IAS as a standard measure; instead, IAS is an operational variable that can be influenced by factors like altitude and aircraft configuration. So, the specific and technical definition of indicated airspeed is accurately captured by the description of dynamic air pressure reflected on the airspeed indicator.