Yes Yes but more important. Understand what you read.

 

This is for me best done by a combination of experience by this forum and the so call manual. No serious school has only a manual.

 

 

Michael Moe

At least at my airline it is half the steady state wind plus all the gusts up to a maximum of 20 knots additive. And that is only if the auto throttles are disengaged. If you leave them on there is no wind additive.

 

And that is also spot on with the Boeing manuals supplied with the NGX.

No serious school has only a manual.

 

No, but they do require you to read it, and will teach with it, rather than sidestepping it, which is a lot of what happens here. You can even see it in this discussion. There are many explanations of the same concept, but a lot of them are littered with what people forgot, or their own idea of what they read.

 

In any case, you won't see adjustments for runway condition in your Vref. You see it on takeoff because it affects the length of your takeoff roll, and aborting that takeoff if necessary. On landing, speed (AoA) is the important thing to keep the plane flying. The only time you see runway condition in landing calculations is your landing roll to see if you can land on that runway, in those conditions.

 

Considering 160kts to the Marker is a rather common ATC instruction...

 

Is it? It's not unusual, but I wouldn't call it common.

 

Additionally, if your Vref means that the instruction is unachievable, your appropriate response would be 'unable'. Controllers are not required to be pilots, and often only have cursory knowledge of what different aircraft are capable of. You need to be their performance guide.

 

Plus, I think the main issue in that discussion would've been capped by a simple mention that the FCTM specifies a maximum addition, as Tom mentioned (20 kts).

Anyone who dares to try explain the Autoland capability as it adds no additive to winds. Does it explain that the aircraft was 20 knots above my landing page in the FMC? Btw did find my answers here by you guys instead of the boring manual. Might be others that have the same experience. Afterall we are simulators right?

 

Questions is the best which lead to answers

 

Michael Moe

 

Forgot to tell that i do read the manual also :-)

 

Michael Moe

 

It seems to me that most airlines are pretty standard in this regard for coming up with the additives. The Boeing manuals do a good job of explaining the procedure, and I think that most airlines would be loathe to come up with their own techniques.

 

RW example - I was flying a 737-900 to Niigata one gusty night. We were landing right at MaxLdgWt 144,000 and our Vref30 was right at 150. So, add the winds up and you came up with a correction of 30kts. But, you can't have more than 20 knots and we were right at F30-5, so the approach was flown at 170kts. The CA was an A330 FO upgrade and I thought we were gonna be hosed, but he rocked the house. Sugo hasyeos sumnida, gi jong nim!

Anyone who dares to try explain the Autoland capability as it adds no additive to winds.

 

You sure about that? The bottom right of the FMC says otherwise, and when you execute the process correctly, you'll see it follow that to the number. The correct adjustment is VREF+5 for the reasons stated in the manual (essentially, because A/T can react a lot quicker than a human could in recognizing and responding to gusts.

 

Does it explain that the aircraft was 20 knots above my landing page in the FMC?

 

No, it doesn't, but you also didn't explain your own technique or procedure. Computers don't arbitrarily do things. Chances are, based on how you knock the manual in your next sentence, the finer details might not have been read, so you may not be doing it properly.

 

Btw did find my answers here by you guys instead of the boring manual. Might be others that have the same experience. Afterall we are simulators right?

 

Glad you were able to find your answers, but the boring manual is where the information came from, so you might as well go to the source. It is and always will be the cleanest (that is to say, free of interpretation or recollection issues), and most reliable source of information.

 

Forgot to tell that i do read the manual also :-)

 

I'm glad. However, if you read the manual, you don't need a whiz wheel to figure it all out (wind correction anyway). The manual has a very simple formula, as mentioned by everyone here. As far as other calculations go, there are various tools for that. There's the CRP-1, and various other "whiz wheels" and slide rules for conversions and other operations.

 

In the end, it seems you just need to separate the different issues:

-Takeoff performance and landing roll deal with achieving the proper performance within the confines of the runway, with the condition of the runway.

-Approach deals with maintaining the appropriate airspeed to keep you in the air.

 

Two separate realms, handled in different ways.

Then it must be my knowledge thats the limitation here :-)

 

Still cant find how the Autoland with flare approach was way off the data my fmc. Vref30 144+8 was initiated. Might be Active sky or something else. Never mind then

 

Michael Moe