A remote pilot is flying beneath a broken cloud layer whose bases are reported at 900 ft AGL. What is the highest altitude the flight may use and still satisfy the Part 107 cloud clearance requirement?

Explanation

Correct answer: 400 ft AGL. Section 107.51 requires the small unmanned aircraft to remain at least 500 ft below the clouds and 2,000 ft horizontally from them, so with bases at 900 ft the highest usable altitude is 400 ft AGL, which also happens to match the general ceiling. Simply staying visually clear of the clouds or leaving only 200 ft of separation violates the vertical minimum, and there is no half-the-ceiling rule.