An ATC procedure used to request pilots to adjust aircraft speed to a specific value for the purpose of providing desired spacing. Phraseology examples: 1. “Increase/reduce speed to Mach point (number).” 2. “Increase/reduce speed to (speed in knots)” or “Increase/reduce speed (number of knots) knots.”

Source FAA Pilot/Controller Glossary↗ · checked 2026-08-25