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Given:

True course: 017°
W/V: 340/30
TAS: 420 kts
Find wind correction angle (WCA) and ground speed (GS)
  • A
    WCA -2°; GS 426 kts
  • B
    WCA -2°; GS 396 kts
  • C
    WCA +2°; GS 396 kts
  • D
    WCA +2°; GS 416 kts

Refer to figure.
Solving from Heading (HDG) & Ground Speed (GS), knowing WV, TAS and required track.

  1. Set wind direction to 340º under the "TRUE HEADING" index at the top.
  2. Set the center point on the True Airspeed (TAS) of 420 kt.
  3. Mark the wind velocity 30 kt down from the centre point.
  4. Initially, set the True Track to 017º under the "TRUE HEADING" index.
  5. Note that this heading would result in 3ºR drift and a track of 020º.
  6. Reduce the heading value under the index until the heading plus the drift gives a track of 017º. This occurs at a heading of 014º with 2ºR drift.
  7. The groundspeed for this track is approximately 396 kt.
Wind correction angle (WCA) is the angle (º) between the Course and the Heading that is required for the aircraft to track that Course when there is wind. Wind Correction Angle is the same value as drift but it is applied in the opposite sense: (-)2ºL WCA
  • Solving this question without a Flight Compute:
Your track: 017° and wind is blowing from 340° at 30 kts => wind is, therefore, 37° from the left and it is rather a headwind. To maintain your track you will have to adjust your heading to the left (into the wind) => making your heading decrease => it will be a "-" WCA.
Since you have a Headwind, your Ground Speed will be lower than your TAS.

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