From the end of an instrumental runway, the approach surface rises outwards A. 1 in 20 B. 1 in 30 C. 1 in 40 D. 1 in 50

1 in 20
1 in 30
1 in 40
1 in 50

The correct answer is: A. 1 in 20.

The approach surface is a standardized surface that defines the required flight path for an aircraft to land on a runway. It is defined as a plane that rises from the end of the runway at a slope of 1 in 20 (1%, or 1 foot of rise for every 20 feet of horizontal distance). This slope is designed to provide a safe and gradual landing for aircraft.

Option B is incorrect because the approach surface does not rise at a slope of 1 in 30. Option C is incorrect because the approach surface does not rise at a slope of 1 in 40. Option D is incorrect because the approach surface does not rise at a slope of 1 in 50.