Vref wind correction

[Guest Ragstar]

Thanks in advance, which value do I enter in for the wind correction when calculating Vref in the NG, crosswind or headwind?Thanks againDean Riches

[downscc 1,327]

Dean: Leave it at 5 kts unless you want to increase it for gusts, which are poorly simulated in FS. Depending on operator, you would add anywhere from half to the full value of the gust factor. The gusts are given in the METAR such as 14018G22 (wind is 18 kts gusting to 22, the gust factor is 4 kts if you're landing 14).Vref is an airspeed so winds are changing your groundspeed at touchdown but not affecting aerodynamics in smooth flight. Gusts represent variability to aerodynamics because the flow over the wing can change much faster than the momentum of the aircraft due to its mass.

[michal 44]

I agree about gusts - they are useless in FS. But some airlines also add 1/2 of the headwind to the Vref. So for example if the headwind is 20 kts they increase Vref by 10 kts.Michael J.http://img142.imageshack.us/img142/9320/apollo17vf7.jpg

[Guest Ragstar]

Ah, add headwind, leave gusts out, thanks

[downscc 1,327]

Michael: Really? This seems counterproductive if the goal is to maintain safe final approach speed and minimize landing ground speed (save on gear and tires). Here in Corpus Christi, our winds are routinely 18-22 kts and 30 is not unusual and we take advantage of it as so does the Navy that trains at least half of their aviators here (and they can move their floating runways into the wind to slow down that landing ground speed). Just wonder where you heard this? Thanks.

[michal 44]

>Just wonder where you heard this? Thanks.Oh, this is mentioned in many places as official Boeing's recommended procedure. You will for example find it here:(btw, maximum added correction is 15 kts)http://www.757.org.uk/sops/sop5.htmlMichael J.http://img142.imageshack.us/img142/9320/apollo17vf7.jpg

[downscc 1,327]

Thanks, interesting info there (I'll assume the same criteria for 737 and 757)... and they state up front that it is insurance against wind shear gradiant and that makes sense if you're a heavy (like a 757). I'm always learning. Thanks again.Edit: The PMDG AOM gives same as your source except max add is 20 kts. (LANDING 3-7)

[michal 44]

>I'm always learning.And I do too. I was also a bit surprised when I found this out.Michael J.http://img142.imageshack.us/img142/9320/apollo17vf7.jpg