A pilot qualification that permits flight by instrument reference. This is necessary in conditions of reduced visibility, such as clouds, fog, or heavy precipitation.
An operating privilege that is attached to a pilot certificate. The pilot is authorized to navigate and control the airplane without visual reference to the ground, such as when flying in or above clouds.
An instrument rating means that a person is a pilot qualified to operate a specific type of airplane under adverse conditions such as darkness, bad weather, and poor visibility.