Keep-Out Altitude is defined as which of the following?

• A. The vertical distance above a defended asset at which a successful engagement denies an adversary's desired weapons effects.
• B. The altitude at which a defensive system achieves optimal tracking accuracy.
• C. The minimum altitude for safe operations over the defended asset.
• D. The maximum altitude allowed for an engagement to be considered valid.

Answer: (A)

Keep-Out Altitude is the vertical distance above a defended asset at which a successful engagement denies an adversary's desired weapons effects. In other words, it’s the altitude boundary used in engagement planning to ensure that if a threat operates within that zone, our fire control solution will produce the necessary effect to prevent the attacker from delivering their weapons.

This concept matters because it defines where we expect to be able to neutralize or disrupt an attack before the adversary can achieve their objective. It’s not about how well we track targets, a minimum safe height for flight, or a maximum height for an engagement to count as valid. Those ideas refer to tracking performance, safety thresholds, or engagement eligibility, respectively, none of which describe the purpose of keeping the enemy from achieving their effects.