What rate of descent is required to maintain a 3-degree glide-slope with a ground speed of 160 knots?

What rate of descent is required to maintain a 3-degree glide-slope with a ground speed of 160 knots?

• A. 400 fpm
• B. 800 fpm
• C. 1200 fpm
• D. 1600 fpm

Answer: (B)

Descent rate on a glide slope is determined by how steep the path is and how fast you’re moving horizontally. For a 3-degree glide slope, the vertical speed you need equals your horizontal speed times tan(3°). Convert 160 knots to feet per minute: 1 knot is about 101.27 ft/min, so 160 knots ≈ 16,200 ft/min. Multiply by tan(3°) ≈ 0.05241, yielding about 850 ft/min. Since the answer choices are standard increments, the closest match is 800 ft/min.

Descent rate on a glide slope is determined by how steep the path is and how fast you’re moving horizontally. For a 3-degree glide slope, the vertical speed you need equals your horizontal speed times tan(3°).

Convert 160 knots to feet per minute: 1 knot is about 101.27 ft/min, so 160 knots ≈ 16,200 ft/min. Multiply by tan(3°) ≈ 0.05241, yielding about 850 ft/min.

Since the answer choices are standard increments, the closest match is 800 ft/min.