WIND DIRECTION/SPEED

[DOC.400]

Could somebody out there explain how the system on, say 747-400, works out the wind speed and direction to show on the display. I assume it's based on track and heading and some trigonometry. Simple reply please!!!

[CaptainSquelch]

Well Doc,

Seems like you gave the simple answer already. The IRS "knows" the true vector of the airplane and the heading. From the Airdata computer it gets the true airspeed and with some simple trigonometry it finds out the wind vector.

Sq