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-   -   HWC/TWC in Pattern (https://www.pprune.org/questions/644074-hwc-twc-pattern.html)

Speedwinner 5th Dec 2021 09:31

HWC/TWC in Pattern
 
Guys,

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

Thanks so much

42go 5th Dec 2021 13:37

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?

dixi188 5th Dec 2021 18:15

Used to have a nice little chart on a clipboard, but I don't suppose you use clipboards these days.

Vessbot 5th Dec 2021 18:23

Pay attention, he asked for the Airbus version. You don't need a clipboard when the airplane is equipped with a tray!

dixi188 5th Dec 2021 20:19

Sorry, my clipboard was for a Mk1 Airbus and I had a table facing sideways.:)

+TSRA 9th Dec 2021 17:20


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

42go 10th Dec 2021 17:56

Ah, never mind.:ugh:


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