Descend or climb at an optimum rate consistent with the operating characteristics of the aircraft to 1,000 feet above or below the assigned altitude, and then attempt to descend or climb at a rate of between 500 and 1,500 fpm until the assigned altitude is reached.

When Air Traffic Control (ATC) issues a descent clearance without a specific "rate" instruction, they generally expect a standard and predictable descent. In 2026, for commercial jet aircraft, this is typically between 1,500 and 2,500 feet per minute (fpm). If a pilot needs to descend more slowly (less than 500 fpm) or more rapidly, they are usually expected to inform ATC, as the controller is planning the "separation" of other aircraft based on these standard rates. During the "Initial Descent" from cruise altitude, a rate of 2,000 to 3,000 fpm is common to stay on the "vertical profile" calculated by the Flight Management System. However, once the aircraft is below 10,000 feet, the rate typically decreases to around 1,000 to 1,500 fpm to ensure passenger comfort and to manage the speed limit of 250 knots. If ATC uses the phrase "Descend at pilot's discretion," the pilot can choose when to start and what rate to use, but they must still notify ATC when they actually leave their current altitude to ensure airspace safety.