If you need to lose 8,000 feet of altitude, how far out should you begin your descent at a groundspeed of 400 knots?

If you need to lose 8,000 feet of altitude, how far out should you begin your descent at a groundspeed of 400 knots?

• A. 30 nm out
• B. 24 nm out
• C. 10 nm out
• D. 15 nm out

Answer: (B)

To determine how far out to begin your descent to lose 8,000 feet of altitude at a groundspeed of 400 knots, you can use a general rule of thumb in aviation: for every 1,000 feet of descent, you should start your descent approximately 3 nautical miles (nm) from your target altitude. In this case, to lose 8,000 feet, you would multiply 8 (the number of thousands of feet) by 3 (the distance in nautical miles per thousand feet). This calculation gives you: 8,000 feet ÷ 1,000 = 8 8 × 3 = 24 nm Therefore, you should begin your descent 24 nautical miles away from your desired altitude, which aligns with the correct answer. This rule helps ensure a smooth and controlled descent, allowing for proper adjustments based on the specific aircraft's performance and environmental factors.

To determine how far out to begin your descent to lose 8,000 feet of altitude at a groundspeed of 400 knots, you can use a general rule of thumb in aviation: for every 1,000 feet of descent, you should start your descent approximately 3 nautical miles (nm) from your target altitude.

In this case, to lose 8,000 feet, you would multiply 8 (the number of thousands of feet) by 3 (the distance in nautical miles per thousand feet). This calculation gives you:

8,000 feet ÷ 1,000 = 8

8 × 3 = 24 nm

Therefore, you should begin your descent 24 nautical miles away from your desired altitude, which aligns with the correct answer. This rule helps ensure a smooth and controlled descent, allowing for proper adjustments based on the specific aircraft's performance and environmental factors.