File talk:ASI ME.png
Poor choice to illustrate the subject.[edit]
While this instrument appears, at first glance, to be a helpful illustration of the concept of IAS vs. TAS, it fails in one very important respect: This IMAGINARY drawing does not show what the knob controls: "Pressure Altitude / Temperature" adjustment -- a defining feature of TAS indicators -- normally displayed in a small window or scale in the upper portion of the instrument.
(See Okla. Univ. tutorial: https://www.youtube.com/watch?v=Qd1oCqzJZPM )
Without this adjustment indicated, there is no practical way to know if the instrument is set properly, and indicating correctly.
Thus, this is a false and misleading image to represent a True Airspeed (TAS) Indicator. (Yes, even the FAA occasionally makes dumb mistakes in its aviation training documents, as any long-experienced flight instructor can report.)
While wholly-automatic self-adjusting True Airspeed Indicators may exist, they do not require the knob on the instrument because they are "automatic."
