PILOT'S DISCRETION
Pilot/Controller Glossary with JO 7110.65BB, Change 3, effective July 9, 2026 · Official text on faa.gov
When used in conjunction with altitude assignments, means that ATC has offered the pilot the option of starting climb or descent whenever he/she wishes and conducting the climb or descent at any rate he/she wishes. He/she may temporarily level off at any intermediate altitude. However, once he/she has vacated an altitude, he/she may not return to that altitude.