When the IRS is set up you tell it where it is, the IRS knows the TAS and heading and time flown and therefore knows where it should be in relation to where it started. The difference between where it thinks it should be and where it calculates it actually is it assumes is due to the wind. This vector is displayed as the wind on the ND.
Can this be true? Surely this vector would be the average wind affecting the a/c from ramp to PPos... ~Bolleaux~ is what I think.
ND displays an
instantaneous wind - the accuracy of the calculation will vary with the accuracy of the inputs.
Tyro