When should an aircraft begin to slow down when entering a hold?

The appropriate moment for an aircraft to begin slowing down when entering a hold is three minutes prior to arrival at the holding point. This timing allows the flight crew to appropriately adjust their speed, ensuring a safe and controlled approach to the holding fix.

By starting to decelerate three minutes in advance, pilots can anticipate any necessary speed reductions due to the configuration of the hold, the aircraft's current speed, and the parameters for entering the hold safely. This advance preparation helps maintain a smooth descent and arrival in the hold, optimizing the overall flight management process.

Starting to slow down only at the holding fix or immediately upon entering the hold may not afford the pilots enough time to stabilize the aircraft speed. Similarly, doing so within 30 seconds of entering the hold is often too close to the point of entry to effectively manage the transition to a holding pattern. Therefore, the three-minute guideline serves as a good practice for pilots to ensure they maintain control and safety while maneuvering into a hold.