Speed Adjustment

An ATC procedure used to request pilots to adjust aircraft speed to a specific value for the purpose of providing desired spacing. Pilots are expected to maintain a speed of plus or minus 10 knots or 0.02 Mach number of the specified speed. Examples of speed adjustments are:
  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: Pilot Contoller Glossary (PCG)