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## Crosswind question

• Posts: 5

### Pilot11 created the topic: Crosswind question

Hi all,

I just had a question regarding crosswinds that I couldn't wrap my head around.
" As height is decreased during a descent to land in a strong crosswind from the right, the crosswind component is likely to-

Select one:
A. Decrease
B. Reverse to come from the left
C. Remain the same
D. Increase"

Any clarification regarding this question would be great help

• John.Heddles
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• ATPL/consulting aero engineer
• Posts: 876

### John.Heddles replied the topic: Crosswind question

Wind is a bit like airflow over a wing - as you get closer to the surface, you get into a boundary layer situation where the wind velocity reduces. For met you may also see a bit of change in direction but the main ask here is the reduction in speed.

There are various mathematical models around the place but the one we use routinely in flight test work is referred to as the 1/7th power law -

(ws1/ws2) = (h1/h2)^(1/7)

where ws is wind speed, h is height about the ground, and 1 and 2 refer to two different heights and their associated speeds. This works pretty well for areas with little terrain ups and downs and minimal cultural things around. You will see this equation, normally in the form of a graph, in numerous flight manuals, especially for larger aircraft.

For the question you have given, they are after (a), the wind speed decreases as you descend near the ground.

Engineering specialist in aircraft performance and weight control.

• Posts: 5

### Pilot11 replied the topic: Crosswind question

Thanks alot sir, your response is appreciated ????

• Posts: 5

### Pilot11 replied the topic: Crosswind question

Apologies, my emoji turned into the four question marks above

• John.Heddles
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• ATPL/consulting aero engineer
• Posts: 876

### John.Heddles replied the topic: Crosswind question

If that's the worst thing which happens today, I don't think I will worry too much. Main thing is that we answer questions so that your knowledge bank increases along the learning pathway.

J

Engineering specialist in aircraft performance and weight control.

• Posts: 3

### smithnoah replied the topic: Crosswind question

I select B "Reverse to come from the left"

• John.Heddles
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• ATPL/consulting aero engineer
• Posts: 876