Airspeed Indicator Markings

The airspeed indicator carries the limits on its face as coloured arcs and a red line, so you can read your margin at a glance.

At a glance

• Red radial line, never exceed154 KTS
• Yellow arc, caution range (smooth air only)125–154 KTS
• Green arc, normal operating range50–125 KTS
• White arc, flap down45–102 KTS

The four markings

• Red radial line — 154 KTS, never exceed.

• Yellow arc — 125 to 154 KTS, the caution range, for smooth air only.

• Green arc — 50 to 125 KTS, the normal operating range.

• White arc — 45 to 102 KTS, the flap down range.

Figure: Airspeed indicator markings (redrawn).

Read the band edges against the airspeed limitations: the top of the white arc is V_FE (102), the top of the green arc is V_NO (125), and the red line is V_NE (154).

Check yourself

• What does the yellow arc cover, and when may you fly in it?

• Where does the green arc start and end?

• Which limit sits at the top of the white arc?

• What speed does the red radial line mark?

Study aid — always fly your aircraft's current AFM/POH.