kijangnim Greetings
Airbus published the same recommendation for the Long range family, So lets apply it
the flight is 9 heures long, the first hour the wind is 270/30, the second hour till destination 270/5 so 25 kts is less than 30 I should not change the wind
First Hour SAT -55 the second hour till destination -59 so it is less than 5 deg , as per Airbus, I should not change it
25 Kts * 8 hours is 200 mn
4 * 8 hours is 32 mn
Total prediction error at destination is 232 mn is terms of time and fuel
Thank you Airbus
I am going to assume mn is nm, but how do you get 4 degrees temperature change time 8 hours equals 32 miles?
If your not happy with an approximation, and/or it disagrees with your flight plan, you might want to put in more accurate data than that recommended. It will blend with actual wind as the flight progresses.
BD