Which statement correctly pairs a surface with its extension rate for a non-precision scenario?

Which statement correctly pairs a surface with its extension rate for a non-precision scenario?

• A. Non-precision approach: 34:1
• B. Precision approach: 34:1
• C. Visual approach: 34:1
• D. Conical surface: 34:1

Answer: (A)

The concept being tested is how obstacle-protection surfaces are defined for different types of approaches, specifically the extension rate that governs how the protective surface rises as you move away from the runway. For a non-precision approach, there is no published vertical guidance, so the protection surface is defined with a relatively shallow extension ratio of 34:1. This means for every 34 units of horizontal distance from the threshold, the surface height increases by 1 unit, creating a broad, gently sloping area that still provides obstacle clearance along the approach path without a glide path. This is the best match because non-precision approaches rely on lateral guidance and step-down fixes rather than a vertical glide slope, so their protective surface uses this 34:1 extension rate. The other surfaces serve different purposes: conical and visual surfaces have their own definitions and are tied to different criteria, and a precision approach includes a published vertical guidance path (a glide slope) with its own protection requirements rather than the 34:1 non-precision extension.

The concept being tested is how obstacle-protection surfaces are defined for different types of approaches, specifically the extension rate that governs how the protective surface rises as you move away from the runway. For a non-precision approach, there is no published vertical guidance, so the protection surface is defined with a relatively shallow extension ratio of 34:1. This means for every 34 units of horizontal distance from the threshold, the surface height increases by 1 unit, creating a broad, gently sloping area that still provides obstacle clearance along the approach path without a glide path.

This is the best match because non-precision approaches rely on lateral guidance and step-down fixes rather than a vertical glide slope, so their protective surface uses this 34:1 extension rate. The other surfaces serve different purposes: conical and visual surfaces have their own definitions and are tied to different criteria, and a precision approach includes a published vertical guidance path (a glide slope) with its own protection requirements rather than the 34:1 non-precision extension.