3° Descent Rate Chart
If you know groundspeed, you can get a useful target vertical speed in a few seconds. The table shows the exact three-degree geometry beside the common groundspeed-times-five shortcut so you can see the difference.
Exact three-degree geometry versus the quick rule
For a three-degree flight path, vertical speed depends on groundspeed. The geometric calculation is groundspeed in NM per minute × 6,076.1 ft/NM × tan(3°). In normal light-airplane ranges, that works out near 5.3 × groundspeed. The familiar groundspeed × 5 rule is easier to do in your head and intentionally runs a little lower.
| Groundspeed | Exact 3° geometry | GS × 5 shortcut |
|---|---|---|
| 60 kt | 318 fpm | 300 fpm |
| 70 kt | 372 fpm | 350 fpm |
| 80 kt | 425 fpm | 400 fpm |
| 90 kt | 478 fpm | 450 fpm |
| 100 kt | 531 fpm | 500 fpm |
| 110 kt | 584 fpm | 550 fpm |
| 120 kt | 637 fpm | 600 fpm |
| 130 kt | 690 fpm | 650 fpm |
| 140 kt | 743 fpm | 700 fpm |
| 150 kt | 796 fpm | 750 fpm |
| 160 kt | 849 fpm | 800 fpm |
| 170 kt | 902 fpm | 850 fpm |
| 180 kt | 955 fpm | 900 fpm |
| 190 kt | 1008 fpm | 950 fpm |
| 200 kt | 1061 fpm | 1000 fpm |
Use the chart as a starting reference, then fly the actual vertical guidance or procedure requirements that apply. Wind changes groundspeed, so the target rate changes too.
Open the 3° descent calculator · Read the descent-rate guide
Source check
The geometry is standard trigonometry. FAA instrument guidance uses vertical-descent-angle and groundspeed relationships; current procedure charts and guidance control an actual approach. See the FAA Instrument Flying Handbook and current procedure publications.