Vector SID- Direct to First Waypoint

[emerydc8]

Hi Hardy, I happened to notice while doing a vector SID out of Gander, RW03, that "vectors" is not replaced with the first fix (DENDU) once HDG SEL is pressed. I can't find anything about this in the FCOM or Honeywell manual, but I found this in an Atlas training guide. Do you have any information on this?

[Avi]

None of my (old) documents mention this. In PSX you must enter an active waypoint to terminate VECTOR (check PSX manual page 375).

Cheers,

[Hardy Heinlin]

I've never heard of this feature.

[emerydc8]

I never have either, but I never looked for it until after I read the above document. It could be one of those features that's there but you could probably fly the airplane for years and never notice it.

[Hardy Heinlin]

"Push HDG SEL to remove the VECTORS condition"

How does the author of this text define "VECTORS condition"?

Is it just the removal of the LNAV guidance within the AFDS?

Or does it include the sequencing of the VECTORS line on the LEGS page (promptly without EXEC requirement)?

If the latter is true, will there be a frozen direct-to line on the ND to the active waypoint from the position which was present in the moment when HDG SEL engaged?

Also: What is the actual trigger? The HDG SEL engagement? Or the LNAV disengagement? In other words, can I also engage HDG HOLD, or even disconnect the whole AFDS to trigger this effect?

[emerydc8]

Without ever actually seeing this -- and maybe Peter can chime in here too -- I would think that pushing HDG SEL brings the first fix up to 1L, draws the dashed white modified route direct to it, and activates the execute light. So all you have to do to go direct is push HDG SEL, EXEC and select LNAV.

[EDIT]: According to the document, it looks like you don't even have to press EXEC. I guess it just draws a direct from PP to the first fix. I think by "vectors condition" he means the 250 HDG (VECTORS) on the LEGS page. It removes that when VTU goes into 1L after pressing HDG SEL.

[Britjet]

That definitely didn't happen at BA.
Peter

[emerydc8]

Hi Peter,
I checked with the Atlas check airman who wrote this training manual. Here is his reply:

Works in our sim and on aircraft. Pretty sure the fix you proceed direct to must be just after VECTORS. If there is a discon or a conditional waypoint after VECTORS, I'm pretty sure it would not work. This technique was specifically taught in 8F training however, been doing it for years on the 400.

Once again, Boeing and Honeywell leave us with nothing in writing. Nothing in the 8F manual or the NG either.

[Hardy Heinlin]

When HDG SEL engages, I guess the ND won't draw a line to the fix; just the LEGS page will get the fix in 1L.

[emerydc8]

That sounds right. Then you would have your heading to the first fix displayed above the waypoint.

EDIT: Are you talking about a modified dashed white line or a magenta line? I think it would draw a magenta line. I was thinking that since there's no need to press EXEC, there will be no modified route -- just the magenta active route.

I think the idea is that you know you will eventually be cleared to the first fix anyway, so it saves the step of having to bring it down to the s/p then up to 1L and executing. One push of the HDG SEL does this for you.

[Hardy Heinlin]

No line at all. And no mod.

[emerydc8]

So if you engaged LNAV at that point (after pressing HDG SEL) it would go direct to the first fix?

[Hardy Heinlin]

Maybe, and then a direct line may be drawn, perhaps, probably, possibly. That would explain why Peter and many others have never seen this feature.

[emerydc8]

The picture above shows a magenta line direct to VTU after pushing HDG SEL. Trying to get more information on this will perhaps, probably, possibly be difficult.

[Britjet]

duplicate post.

[emerydc8]

You are saying that any movement of the HDG bug (even on the ground presumably) will remove the vectors line from the FMC?

On the ground, LNAV is not active, so this won't work on the ground. After takeoff, LNAV is active and it would take a push of the HDG SEL to make HDG SEL active. That would have the effect of moving the first waypoint up to 1L and executing.  Movement of the HDG SEL is not what activates it -- it's pushing in on the HDG SEL knob.

[Britjet]

Another one to try in the sim next week. JFK should do it.
I will eat my socks if this works, though. You are saying that any pushing of the HDG bug (even on the ground presumably) will remove the vectors line from the FMC? I have never seen that...
What I have seen many times is the aircraft being set up in LNAV, and then being given a take-off vector, so HDG SEL is set and pushed before take-off - but I don't ever recall seeing it remove the vectors line. Still...
In the meantime I am off to buy some new socks......

Peter

[Britjet]

Sorry Jon, my edit crossed with your post.
Peter

[emerydc8]

I hate when that happens.

[Hardy Heinlin]

http://www.mypetwarehouse.com.au/veggie-patch-edible-socks-nibblers-x4-p-21842