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Given the following information, what is the wind velocity (°(T))?

TAS: 465 kt
Track: 090°(M)
Variation: 15° E
Wind Correction Angle: +13°
Groundspeed: 480 kt

  • A
    197°/110 kt
  • B
    15°/110 kt
  • C
    360°/110 kt
  • D
    209°/108 kt
Refer to figure.
Convert magnetic track into true track:

Use the mnemonic:

  • Variation West, Magnetic Best.
  • Variation East, Magnetic Least.
True direction
Magnetic direction (M)
105º 15ºE 090º

Follow the steps detailed below in order to find unknown wind

Course/Track and GS are the references related to the path of the aircraft over the ground, and we will start with them.
(1) Place the track (105º) under the true index.
(2) Place the centre of the rotating disk on the value representing the ground speed (480 kt).
(3) Maintaining the central grommet over the GS line, find the point where WCA crosses the TAS and make a pencil mark.

  • Remember that "+" WCA indicates a right WCA. Whereas a "-" WCA indicates a WCA to the left.

(4) Rotate the azimuth disk until the pencil mark is on the centerline between the grommet and the true index.
(5) Determine the wind velocity by counting the lines between the grommet and the pencil mark: 108 kt (588 kt - 480 kt).
(6) Read the true wind direction under the true index: 209º.

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