Aeronautical Information Manual

AIM 4-2-11

Speeds

This reproduces published FAA reference text for study. It does not replace the current official FAA publication or regulation.

The separate digits of the speed followed by the word “KNOTS.” Except, controllers may omit the word “KNOTS” when using speed adjustment procedures; e.g., “REDUCE/INCREASE SPEED TO TWO FIVE ZERO.”

EXAMPLE-

(Speed)

250 two five zero knots

(Speed)

190 one niner zero knots

The separate digits of the Mach Number preceded by “Mach.”

EXAMPLE-

(Mach number) 1.5 Mach one point five

(Mach number) 0.64 Mach point six four

(Mach number) 0.7 Mach point seven

Retrieved from ecfr.gov on July 20, 2026.