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HWC/TWC in Pattern

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HWC/TWC in Pattern

Old 5th Dec 2021, 08:31
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Question HWC/TWC in Pattern

Guys,

some quick formula how to calculate the TWC/HWC in the pattern in a A320?

Thanks so much
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Old 5th Dec 2021, 12:37
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If it is any help, for a Cessna 150 the headwind component is (Cosine of the angle of the wind off your heading) x (the wind speed).

eg 45 degrees off = .7 x wind speed: 90 off = 0: on the nose = wind speed.

I'm sure you can adapt that to an A320?
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Old 5th Dec 2021, 17:15
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Used to have a nice little chart on a clipboard, but I don't suppose you use clipboards these days.
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Old 5th Dec 2021, 17:23
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Pay attention, he asked for the Airbus version. You don't need a clipboard when the airplane is equipped with a tray!
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Old 5th Dec 2021, 19:19
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Sorry, my clipboard was for a Mk1 Airbus and I had a table facing sideways.
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Old 9th Dec 2021, 16:20
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If it is any help, for a Cessna 150 the headwind component is (Cosine of the angle of the wind off your heading) x (the wind speed).

eg 45 degrees off = .7 x wind speed: 90 off = 0: on the nose = wind speed.

I'm sure you can adapt that to an A320?
The funny thing is, the math doesn't change and the airplane doesn't care. Cosine of the wind angle x wind speed works every time, no adaptation necessary. The only difference is that in something like a 320, you've got much less time to figure it out than a single-engine Cessna. Operationally, you've got to find a quicker way to figure it all out that is not formula-based - you don't have time to plug in the variables doing 200 to 250 knots. So, use the cosine method described above, and even if you just remember a few of the values as a function of speed you're fine. I've committed every 20 degrees to memory and then add or take off a bit as necessary. It works well enough:
  • 5-degree crosswind equals 99% of the wind speed
  • 25-degree crosswind equals 90% of the wind speed
  • 45-degree crosswind equals 70% of the wind speed
  • 65-degree crosswind equals 44% of the wind speed
  • 85-degree crosswind equals 87% of the wind speed

Last edited by +TSRA; 9th Dec 2021 at 16:20. Reason: Removed a spurious bullet point
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Old 10th Dec 2021, 16:56
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Ah, never mind.
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