What term indicates bad or no braking action on an airport surface?

• A. Bad
• B. Zero
• C. Poor
• D. Nil

Answer: (D)

Braking action describes how well tires grip the runway surface and thus how effectively an aircraft can slow down. The usual scale runs from good to nil. Nil is the term used to indicate no braking action at all—the surface provides essentially no friction for deceleration. It’s the strongest warning that braking is unavailable, so operations would be restricted or paused until conditions improve.

Other terms like poor describe limited braking with some friction still available, but not a complete loss. Bad or zero aren’t standard aviation descriptors for braking action, so they don’t convey the official meaning as clearly as nil does. Nil, therefore, is the best answer because it communicates the absence of usable braking action.