At an altitude of 24,000 ft, when should you start your descent to reach 18,000 ft?

To determine when to start your descent from an altitude of 24,000 feet to reach 18,000 feet, it is important to consider the general rule for descent planning in aviation. A common guideline is to begin your descent at a rate of approximately 1,000 feet per 3 nautical miles. The altitude change from 24,000 feet to 18,000 feet is a total of 6,000 feet.

Using this guideline, you would calculate the required distance for the descent as follows:

1. Since you are descending 6,000 feet, you would divide this by the rate of 1,000 feet per 3 nautical miles, leading to:

• 6,000 feet / 1,000 feet = 6

• 6 * 3 nautical miles = 18 nautical miles

Therefore, starting your descent 18 nautical miles before reaching the waypoint at 18,000 feet aligns with this guideline and is the correct approach. This allows adequate time for a gradual descent, ensuring comfort for passengers and maintaining control of the aircraft throughout the descent.