Introduction / Context:
Runway orientation is one of the most important early decisions in airport planning. The goal is to minimize crosswind components during landing and take-off to improve safety and reduce runway length requirements.
Given Data / Assumptions:
- Wind roses derived from multi-year observations represent the prevailing wind directions and speeds.
- Pilots prefer headwinds for lower ground speed at touchdown and rotation, reducing required distances.
- Crosswind limits depend on aircraft category and runway code.
Concept / Approach:
Align the runway so that operations are predominantly into the wind, maximizing headwind components and minimizing crosswind exceedances above allowable limits. This is the basis for choosing runway headings and, where needed, providing multiple runway orientations.
Step-by-Step Solution:
Identify dominant winds from wind-rose charts.Select runway bearings that align with the most frequent wind directions to ensure headwind or minimal crosswind for the largest share of time.Validate by calculating crosswind components against aircraft limits to confirm acceptability.
Verification / Alternative check:
Compute crosswind component = wind_speed * sin(difference in bearing). Smaller differences give smaller crosswinds, confirming into-wind orientation is optimal.
Why Other Options Are Wrong:
b: Downwind alignment increases landing/take-off distances and risk.c: Perpendicular alignment maximizes crosswind, which is undesirable.d/e: Not standard planning practice and would fail crosswind criteria.
Common Pitfalls:
Confusing runway numbering (magnetic heading/10) with wind direction; assuming a single runway can satisfy all seasonal winds without considering a cross runway where necessary.
Final Answer:
Against (into) the wind direction
Discussion & Comments