NGX Vref Wind Correction

[bob34 124]

After all these years, I'm a bit embarrased to ask this, but here goes.

 

Vref on the FMC is showing 138kts on my current approach.

For the first time, I realized there's a line below that says "wind correction +5kts".

 

Typically, I use Vref +5kts for my approach - so tonight I would use 143kts.

 

But now I'm wondering of the FMC added the 5kts for me and real Vref is 133kts - and the 138 is Vref +5.

 

Can anyone clear this up for me?

 

Thanks,

 

Bob

[Spin737 102]

You select your flaps and weight, and the box spits out the Vref. You can leave the +5 wind correction, and the plane will show the correct Vapp speed. If you need to change the wind additive, you can do that by overwriting the +5 with whatever you need, up to +20.

 

You don't need to overwrite the Vref unless you're doing some abnormals.

 

Vapp is Vref+additives.

[bob34 124]

So if I'm in turbulence, and want +10, overwriting in the FMC will change the command speed?

[megs8888 20]

Hi I am interested in this can someone give an example of how to do this? When I select the flaps approach on perf init page by clicking twice do I add the very speed in the mcp on approach + 5 or will it add this automatically? Thanks

 

 

Sent from my iPad using Tapatalk HD

[Tabs 2,790]

The NG FMC automatically adds 5 knots to Vref. What you see next to the flap setting on the APPROACH REF page is the actual Vref value. What's on the LEGS page at the runway waypoint is the Vref+wind.(Interestingly, the 777 is *completely* different with respect to this phase of flight and does not do any of this - it's a key difference between the two planes that NGX pilots will have to get used to)

Bob,

All you have to do there is change it to +10 on the APPROACH REF page. This isn't of all that much consequence in most operations though because you'll likely have MCP control of the speed unless you're doing an approach that involves using VNAV instead of an ILS or whatever. With an ILS just take your Vref speed and enter in that speed plus 10 on the MCP - no need to mess with the FMC. In fact, even if you were doing a VNAV approach, you could just speed intervene and set it manually that way too.

[hopskip 253]

Little tip I heard one day.

 

If you rotate the MCP speed control down till the bottom of the magenta 'selected speed' is resting on the green -vref speed bug on the PFD, you have just selected Vref+5

[Spin737 102]

Little tip I heard one day.

 

If you rotate the MCP speed control down till the bottom of the magenta 'selected speed' is resting on the green -vref speed bug on the PFD, you have just selected Vref+5

That's how I do it 90%, but if you've got an additive (or you find yourself in a -400) it doesn't work as well.

[bob34 124]

 

 

All you have to do there is change it to +10 on the APPROACH REF page.

 

Perfect. Just wanted to confirm that the + didn't recalculate the vref #. And in hindsight, I could have played with it to find out.

[Driver170 42]

Do you have to still add + 5 to your vref or is it already added to the vref on the approach page vref speed?

[Spin737 102]

The Vref shown is the Vref for the displayed weight.

 

The wind correction of 5kts is the default. If you want something higher, put it in the wind correction.

 

The legs page will show the final speed of Vref plus your wind correction.

[Driver170 42]

Ahh i see so if i have + 5 in the approach page the default speed and my vref is 140 in the legs page will show 145 yeh?