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Given the following information, what is the headwind component that should be taken into account for take-off performance purposes?

Take off direction: 360°(M)
Reported Surface wind: 015°(M)/5 kt

  • A

    5 kt

  • B

    4.8 kt

  • C

    2.5 kt

  • D


The wind velocity is made of two components, one acting along the take-off direction called the headwind component, and the other acting across the take-off direction called the crosswind component.

It is possible to calculate the crosswind component taking the sine and the cosine of the angle difference between the take-off direction and the wind direction:

  • Headwind component = Wind Speed x cos(Take off - Wind direction)
  • Crosswind component = Wind Speed x sin(Take off - Wind direction)

Thus, Headwind component = 5 kt x cos 015° = 4.8 kt.

According to CAT.POL.H.105 - General:

When showing compliance with the requirements, among others, account shall be taken of the environmental conditions, concerning the wind conditions:

(A) except as provided in (C), for take-off, take-off flight path and landing requirements, accountability for wind shall be no more than 50% of any reported steady headwind component of 5 kt or more;

Since, the reported headwind component is 4 kt (less than 5 kt), then it should not be taken into account for take-off performance purposes.

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