Definition
A chart, supplied in the Pilot's Operating Handbook, that shows the difference between the airspeed indicator's reading (indicated airspeed) and the actual calibrated airspeed at various flap and configuration settings. It allows the pilot to correct for installation and instrument error in the airspeed indicating system.
Plain English
A small table or graph from your aircraft's handbook that tells you what the real airspeed is when your airspeed indicator shows a particular number. The needle on the gauge is rarely perfectly accurate, so this chart shows you the correction.
Context Anchor
Seen in the airplane’s operating handbook when comparing indicated airspeed with calibrated airspeed, especially during slow flight, approach, landing, or performance calculations.
Derivation
Calibration comes from the Latin 'calibra,' referring to the bore of a gun, and later came to mean checking or adjusting an instrument against a known standard. On this chart, the indicator's readings are compared against known correct values.
Why Pilots Care
Using the chart ensures airspeed values used for takeoff, landing, and stall margins are accurate rather than slightly off due to the airplane's pitot-static installation.
Intuition Check
Do not think of this as a navigation chart or map. In this context, “chart” means a correction table or graph for the airspeed indicator.
Example Sentence 1
Before practicing slow flight, she checked the airspeed calibration chart and noted that her indicator read three knots low with full flaps.
Example Sentence 2
The airspeed calibration chart showed a two-knot correction at approach speed, confirming the correct target on the indicator.