📚 How to Calculate Top of Descent
The 3:1 rule is the simplest method for calculating your descent point: for every 1,000 feet you need to descend, start 3 nautical miles before your target.
The Formula
Distance (NM) = (Altitude to lose / Descent rate) × (Ground speed / 60)Example
Flying at FL350 (35,000 ft), targeting 3,000 ft pattern altitude:
- Altitude to lose: 32,000 ft
- Descent rate: 1,800 fpm
- Ground speed: 450 kts
- Result: Start descent ~133 NM out
Tips for MSFS 2024
In Microsoft Flight Simulator 2024, the most common mistake is starting descent too late. Aircraft with modern avionics (A320, B737) will show you a TOD marker on the ND, but it's always good to verify manually.
PilotLeague tracks your actual descent profile and compares it to the ideal path. You'll see exactly where you deviated and how it affected your score.