In airport planning and runway orientation analysis, the most suitable direction for a new runway should align with the dominant wind indicated by the longest line on the wind-rose diagram to maximize headwind coverage and minimize crosswind components.
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Alongest line on wind rose diagram
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Bshortest line on the wind rose diagram
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Cline clear of wind rose diagram
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Dnone of these.
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Emedian line of wind occurrences regardless of length
Answer
Correct Answer: longest line on wind rose diagram
Explanation
Introduction:Runway orientation is a foundational decision in airport engineering. The objective is to align the runway so that aircraft take off and land as nearly as possible into the prevailing winds. The wind-rose diagram summarizes frequency and direction of winds; its longest spoke highlights the most frequent wind direction, which is typically the preferred alignment to reduce crosswind components and improve operational reliability.
Given Data / Assumptions:
- A wind-rose diagram is available for the site with directional frequencies.
- Aircraft performance is better with headwind components and is limited by crosswind components.
- Standard planning seeks maximum wind coverage, often targeting 95% availability within allowable crosswind limits.
Concept / Approach:
Select the runway alignment that maximizes headwind exposure while keeping crosswinds within aircraft limits. The longest wind-rose line corresponds to the direction with the highest frequency of winds, thus offering the best alignment for routine operations and reduced crosswind closures.
Step-by-Step Solution:
Identify the direction of maximum wind frequency from the wind-rose: the longest spoke.Map that direction to a candidate runway centerline bearing.Evaluate crosswind coverage; a longest-spoke alignment typically maximizes compliance.Therefore, choose the alignment along the longest wind-rose line.Verification / Alternative check:
Cross-validate with wind coverage calculations. Aligning the runway along secondary directions (shorter spokes) generally decreases coverage and increases crosswind exceedances.
Why Other Options Are Wrong:
- Shortest line: Represents infrequent winds; poor coverage.
- Line 'clear' of diagram: No statistical support; not data-driven.
- None of these: Incorrect because there is a clear best practice.
- Median line regardless of length: Ignores frequency; can increase crosswind exceedances.
Common Pitfalls:
- Confusing mean wind direction with most frequent direction.
- Ignoring seasonal or diurnal wind patterns without adequate data duration.
Final Answer:
longest line on wind rose diagram