Which statement correctly identifies the extension rate for a precision approach?

Which statement correctly identifies the extension rate for a precision approach?

• A. The approach surface for precision approaches extends at 50:1
• B. The approach surface for precision approaches extends at 20:1
• C. The approach surface for precision approaches extends at 34:1
• D. The approach surface for precision approaches extends at 7:1

Answer: (A)

The key idea is the slope of the approach surface, which protects the instrument approach path by defining how the surface rises as you move away from the runway end. For a precision approach, the standard extension rate is 50:1, meaning the surface climbs 1 foot for every 50 feet of horizontal distance. This relatively gentle slope creates the required obstacle clearance along the longer, more exacting precision approach path. In practical terms, at 1,000 feet from the threshold the surface is about 20 feet above the runway, and at 5,000 feet it’s about 100 feet up. The other rates would define different surfaces and aren’t the standard for precision approaches.

The key idea is the slope of the approach surface, which protects the instrument approach path by defining how the surface rises as you move away from the runway end. For a precision approach, the standard extension rate is 50:1, meaning the surface climbs 1 foot for every 50 feet of horizontal distance. This relatively gentle slope creates the required obstacle clearance along the longer, more exacting precision approach path.

In practical terms, at 1,000 feet from the threshold the surface is about 20 feet above the runway, and at 5,000 feet it’s about 100 feet up. The other rates would define different surfaces and aren’t the standard for precision approaches.