In airport planning per ICAO/Indian practice, if the width of the approach area near the runway end is 150 m, what will be the width of the approach area at a distance of 3 km from the runway end (considering the standard outward splay)?

Introduction / Context:
The approach surface (also called the approach area) is a protected airspace wedge ahead of a runway that widens with distance to provide obstacle clearance during landing. Its inner edge lies at the threshold and its width increases outward according to a prescribed divergence (splay). This question tests recognition of the standard geometric widening used in classical exam problems when the inner width at the threshold is given and the outer width at a benchmark distance (3 km) is asked.

Given Data / Assumptions:

• Inner edge width at runway end (threshold) = 150 m.
• Distance from threshold along approach surface = 3 km.
• Adopt the standard widening used in typical ICAO-based exam tables for non-precision/precision approach surfaces where the outer width at 3 km is taken as a canonical value.

Concept / Approach:
In many Indian transportation-engineering references, the approach area is assumed to expand laterally to a conventional outer-edge width by 3 km. For inner width 150 m, the commonly quoted outer width at 3 km is 1200 m. This reflects a total side divergence consistent with classic study tables and is frequently tested as a memory-based fact rather than a derivation-heavy calculation.

Step-by-Step Solution:
Identify approach geometry: inner edge = 150 m at threshold.Recall standard MCQ value for the outer width at 3 km: 1200 m.Select the option matching 1200 m as the widened width at 3 km.

Verification / Alternative check:
Several standard handbooks list the 150 m inner edge with an outer width near 1200 m at 3 km for typical approach surfaces used in exam questions. While detailed ICAO Annex 14 tables vary with runway code and type, the 150→1200 convention is a widely accepted learning figure.

Why Other Options Are Wrong:

• 1500 m, 1000 m, 800 m: Do not match the standard conventional value tied to the 150 m inner edge used in such exam problems.

Common Pitfalls:

• Trying to re-derive from first principles without the specific divergence; many MCQs expect the memorized 1200 m value at 3 km for a 150 m inner width.
• Confusing approach surface with takeoff climb or transitional surfaces, which have different splay rules.

Final Answer:
1200 m