Indicated Airspeed (IAS)
Indicated Airspeed (IAS)
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22.Nov.2025
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SKYbrary Aviation Safety. (November 22, 2025). Indicated Airspeed (IAS).
Retrieved June 4, 2026
from https://skybrary.aero/articles/indicated-airspeed-ias
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Definition
The airspeed shown on the flight-deck instrument.
Description
An aneroid instrument, the airspeed indicator measures the dynamic pressure of the outside air entering a pitot tube. At sea level, and an atmospheric pressure of 1013.2 mb, and with no wind effect, the airspeed indicated is the true speed of the aircraft relative to the surface. As the aircraft climbs, the air density decreases and the indicated speed will be less than the True Air Speed (TAS). However, when it comes to controlling the aircraft, because the flight characteristics of the aircraft also alter with reduction in atmospheric density, the indicated airspeed is of greater importance than the true airspeed. This is why control speeds (e.g. V1, V2, etc) are given as KIAS (Knots Indicated Airspeed).
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- Airspeed Conversion
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- Ground Speed
- Holding Pattern
- International Standard Atmosphere (ISA)
- Never Exceed Speed (Vne)
- B738, en-route, west of Canberra Australia, 2017
- Aerodynamic Stall Awareness and Avoidance
- Basic Controller Techniques: Speed Control
- Conflict Detection
- Bird Strike Reporting
- High-Altitude Flight Operations
- Stall
- Unreliable Airspeed Indications
- Autorotation
- Calibrated Airspeed (CAS)
- Equivalent Airspeed (EAS)
- Hot and High Operations
- Mach Number
- Stability
- True Airspeed
- Altimeter
- Cross Wind Takeoff Hazards and Techniques
- Low Level Wind Shear
- Microburst
- Pitot Static System
- Pressurisation Problems: Guidance for Flight Crews
- Short Vectoring and Glideslope Interception from Above: Guidance for Controllers
- Short Vectoring and Glideslope Interception from Above: Guidance for Flight Crew
- Spoilers And Speedbrakes
- Tailwind Operations
- Volcanic Ash: Guidance for Flight Crews
- Performance shear
- B738, en-route, east southeast of Adelaide Australia, 2017
