Editing Indicated airspeed (section)

==IAS and navigation==

For navigation, it is necessary to convert IAS to [[true airspeed|TAS]] and/or [[ground speed]] (GS) using the following method:
* correct IAS to [[calibrated airspeed]] (CAS) using an aircraft-specific correction table;
* correct CAS to [[true airspeed]] (TAS) by using [[Outside air temperature|Outside Air Temperature (OAT)]], Pressure-altitude and CAS on an [[E6B]] flight computer or equivalent functionality on most [[Global Positioning System|GPS]]s;
* convert TAS to [[ground speed]] (GS) by allowing for the effect of [[wind]].

With the advent of [[Doppler radar]] navigation and, more recently, [[Global Positioning System|GPS]] receivers, with other advanced navigation equipment that allows pilots to read [[ground speed]] directly, the TAS calculation in-flight is becoming unnecessary for the purposes of navigation estimations.

[[true airspeed|TAS]] is the primary method to determine aircraft's cruise performance in manufacturer's specs,<ref name=":1" /> speed comparisons and pilot reports.