Star to approach transition question

[gmohr 0]

Hey all,When flying a star to approach, I noticed a few oddities. If the end of the star coincides with the first fix in the approach, all is easy. If they differ then either:1) there will be a (vectors) entry in the legs page to indicate atc transition, or2) there will be a discontinuity in the legs pageHow should 2) be dealt with. Ive noticed this even occasionaly when the star should include vectors as per the chart. Whats the right procedure here? Fly it with the discontinuity, or somehow insert a (vectors) leg in the FMC (if so, how?)Thanks!George

[William J.S.S 173]

Most stars in the US will include a note that after a certain fix, there will be vectors. I pull up my charts, see where my last fix will dump me, program my approach if I feel like it, get my course and frequency for the RWY, and vectors myself for a line up to capture the Loc.

Edited February 9, 2012 by William J.S.S

[scandinavian13 5,192]

If you suspect vectors, never insert a "vector" leg in the FMC. If ATC is vectoring, they will be providing wind correction in that vector. If you add in a vector leg, one, it may not be what ATC would give you, and two, the plane will compensate for the wind on that heading. That second point is important because if I say "fly heading 180" because the wind is so strong it'll make you track 190 and you set a vector leg of 180 in the FMC, you'll track 180 when everyone else is tracking 190, which means you're out of place, and not where I expect you when I glance back at where you should be.To be honest, this whole idea that the magenta line goes from departure to destination is a huge sim-ism. I can't think of the last time I was on a STAR that dumped right onto an approach. I know there are some out there, but I can't think of many in the US.

[Guest]

I always simply line select the first way point after the 'vector' entry and then click to the left of that vector entry. Bye bye vector. :( So I treat is just as a discontinuity! After that I do check the plan step by step in 'PLAN' mode to see if really strange things happen or not. But well, I am not going for total realism, so if I don't like a certain part of turn, I simply line select it out of the plan... :wink:I have to say I always use FS Commander to figure out which STAR I need and I only select a transition if the STAR doesn't connect too well with the final approach fix. If things really get messy and I can't find a good STAR or transition, I don't even mind to fly straight tho the approach fix... But as I said, I am not in it for total realism.

Edited February 9, 2012 by J van E

[Spin737 102]

If they should link, ie. not a vector, then there should be no disco. If there is a vector, there should be a disco. Discos are not inherently bad, so don't worry if an appropriate one is there.Post an example of what you're looking at and we can get a better idea.

[bjratchf 80]

how do I program a vector in to get rid of the discontinuity (and prevent the FMS from getting "angry")

[Sekstifire 10]

You cannot program a vector leg. Those are for premade procedures only.

[Spin737 102]

how do I program a vector in to get rid of the discontinuity (and prevent the FMS from getting "angry")

When you say angry, do you mean you get an FMC message? You shouldn't get a disco message if it's supposed to be there. Can you get some screen caps?

[jturie 0]

Personally I leave the vector in the FMC. When I hit the last waypoint before the vector, I let the plane continue along the vector heading and I dial up a heading and switch to HDG SEL when that heading provides me with a nice entry angle into the ILS outside of the next waypoint on the FMC. If you just delete the vector and have the FMC send you directly to the next waypoint (the first on the ILS), a lot of times you will intersect the ILS way too close to the airport and maybe even too high to properly snag the glideslope. If you fly online you will need to do this, because ATC will never send you direct to that next waypoint--usually they will give you several course changes that line you up nicely for the ILS.

[scandinavian13 5,192]

Discos are not inherently bad, so don't worry if an appropriate one is there.

Exactly.

Personally I leave the vector in the FMC. When I hit the last waypoint before the vector, I let the plane continue along the vector heading and I dial up a heading and switch to HDG SEL when that heading provides me with a nice entry angle into the ILS outside of the next waypoint on the FMC. If you just delete the vector and have the FMC send you directly to the next waypoint (the first on the ILS), a lot of times you will intersect the ILS way too close to the airport and maybe even too high to properly snag the glideslope.If you fly online you will need to do this, because ATC will never send you direct to that next waypoint--usually they will give you several course changes that line you up nicely for the ILS.

This is what should be done. In many cases, you will not get to LNAV all the way to your destination. It's just the way things work. Don't slave yourself to the magenta line or the FMS. They're there to help you, not own you. If there's a disco/vector, leave it. Vector yourself using HDG SEL, and then if you need to, use LNAV when you get closer to the 'new' leg.

[bjratchf 80]

yeah- not "angry" per se- but the FD references disappear unless I put the aircraft in HDG SEL mode (which is natural after a fix, you'd be flying headings). Maybe this is the real procedure for the FMS- leave the discontinuity in, and just go off of HDG SEL until you intercept final.I'm unable to get screen caps at the moment- right now I'm combatting constant OOMs in the NYC area using the FSDT scenery of KJFK.

[Spin737 102]

How about which STAR and approach? What do the legs say before you start modifying them?

[scandinavian13 5,192]

Maybe this is the real procedure for the FMS- leave the discontinuity in, and just go off of HDG SEL until you intercept final.

This would be correct. When placed on vectors, you should be on HDG SEL until intercepting the LOC. No need to clear the disco. Edited February 9, 2012 by scandinavian13

[Tabs 2,790]

Just want to point out one thing here - if the SIDSTAR procedure is coded correctly (HDG 123 VECTORS, not TRK 123 VECTORS) the plane will in fact fly a heading and not the wind corrected track. The (VECTOR) leg type is a real thing on the real FMC, that's not something we made up for simming.

[yos233 1]

The simple answer (if you just wanted to keep flying LNAV without any actual vectors or anything) would be to select the fix below the discontinuity, and then replace the discontinuity with the fix. So if the the disco is at 2L, then take the fix at 3L and place it on top of 2L.