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moey124

ils approach do I press loc or app on mcp

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Wel I clicked loc and the plane turned to the runway and when should I click app or loc is the same &@($* app on mcp. Cause my plane wasnt descending.

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LOC is just the localizer. APP would be the actual approach, which you would press once the glideslope comes alive.

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Wel I clicked loc and the plane turned to the runway and when should I click app or loc is the same &@($* app on mcp. Cause my plane wasnt descending.

 

I'm only a novice but on an ILS approach I think you just need to press APP to pickup the glideslope. I am not pressing the LOC button at all. APP seems to capture both the localiser and glideslope.

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Usually you would capture the localizer first, and then the gs. So 1st hit LOC and then APP after

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I'm only a novice but on an ILS approach I think you just need to press APP to pickup the glideslope. I am not pressing the LOC button at all. APP seems to capture both the localiser and glideslope.

Not all approaches are full ILS approach. There are some that are localizer only approaches, which is where the LOC button also comes in handy.

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But how do u know when u entrred the glidescope cause I hit loc and it truned to rjnway after passing one more star on the display I hit app but it didnt desend

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LOC will follow the Localizer. 

 

This is a system which transmits a radio beam of sorts that shows where the aircraft needs to track, and will cause the autopilot or flight director to command a correction - left or right - if it detects any deviation of the course from the radio beam's centreline (which at some places like Innsbruck or Kai Tak would be a radio transmitter on a hill somewhere, but at most airports would be a radio transmitter at the far end of the runway you are landing on).

 

APP mode follows both the localizer and the glideslope.

 

I repeat, LOC does NOT follow the glideslope.

 

The glideslope is like the Localizer, but it defines a descent path. If your autopilot is in APP mode, it will follow the descent path, and make corrections - up or down - if it detects any deviation of the glidepath defined by the radio beam's centreline (which at some places like London City EGLC is a 6.6° decent angle, but at most airports is closer to 3°.)

 

 

If you arrive at an airport ILS and press the LOC button, it will fly a track which flies directly over the runway centreline. It will maintain whatever altitude you have set on the Altitude Hold on the MCP.

 

so you will fly over the runway, dead on centre with the white lines in the middle of the runway, at 3000ft above the runway.

 

On the 777 here, there's an airline option to inhibit glideslope intercept in APP mode if you are not established on the Localizer. This means that when you hit the APP mode, the aircraft will need to be in LOC mode (Green, not Armed/White look at the PFD) before the Glideslope can capture. If you arrive "Above glideslope" then it will not 'descend to meet the glideslope'. This means the aircraft will not descend with the glideslope when it is not near the localizer. This is deliberate to protect the aircraft from descending with the glideslope when it isn't on course. an ILS has a surveyed protected area where by the glideslope is guarenteed to not hit hills and buildings etc. If you are 3 miles left of that, the glideslope might hit a hill, causing lots of dead 777 passengers. To avoid this, intercept the localizer on vertical profile if on an RNAV arrival, or as a general rule when using self-vectoring, more than 12 miles out and no more than 3000ft above the airport elevation.

 

In the PMDG 777, there's an option to turn this feature off, and so you can intercept and descend with the glideslope in APP mode even if you are well left or right of the localizer. This way the Autoland will still arm, and... assuming you don't crash into hills and structures on the way down, touch down on the glideslope somewhere near the runway, possibly even on it.

 

Here's some more things to consider when using an ILS. (To avoid confusion, this "False/Erroneous glideslope" problem won't happen in Flightsim FSX)

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LOC should always be selected first. After established on the LOC (LOC green on FD), if you require a full ILS/Autoland, then press APP. GS will display in white on the FD until glide slope capture, at which point GS will turn green.

 

Regards,

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LOC should always be selected first. After established on the LOC (LOC green on FD), if you require a full ILS/Autoland, then press APP. GS will display in white on the FD until glide slope capture, at which point GS will turn green.

 

Regards,

 

"Always" is a pretty strong term.

 

Try the LIZZI7A Arrival 16 at YMML, It's an RNAV with a 180kt max speed 90 degree left turn at 4000ft 13 DME from Melbourne.

 

The localizer and glideslope both intersect the RNAV section IN the turn at Bolinda BOL (ndb 362)

 

If you have APP mode selected as you start the turn, you will roll out wings level descending and with LOC & GS mode active.

 

If you don't... you'll probably be at 4000ft 2 dots above slope and increasing.

http://www.airservicesaustralia.com/aip/current/dap/MMLSR05-135.pdf

 

Without rolling the MCP altitude window down and getting onto FLCH quick smart, then getting back on glideslope will be a bit of a battle. Intercepting the Glideslope from above out of FLCH is an option, but it's not the best option.

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"Always" is a pretty strong term.

 

Try the LIZZI7A Arrival 16 at YMML, It's an RNAV with a 180kt max speed 90 degree left turn at 4000ft 13 DME from Melbourne.

 

The localizer and glideslope both intersect the RNAV section IN the turn at Bolinda BOL (ndb 362)

 

If you have APP mode selected as you start the turn, you will roll out wings level descending and with LOC & GS mode active.

 

If you don't... you'll probably be at 4000ft 2 dots above slope and increasing.

http://www.airservicesaustralia.com/aip/current/dap/MMLSR05-135.pdf

 

Without rolling the MCP altitude window down and getting onto FLCH quick smart, then getting back on glideslope will be a bit of a battle. Intercepting the Glideslope from above out of FLCH is an option, but it's not the best option.

I stand corrected. I should have said "almost without exception" however for the benefit of the OP, read the last paragraph on page 91 of Tutorial #1.

 

Regards,

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Another instance that will happen is that ATC will give a clearance to intercept the localizer but not clearance for the approach.

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Another instance that will happen is that ATC will give a clearance to intercept the localizer but not clearance for the approach.

Would this be if ATC was considering issuing a side step in the case of parallel runway?

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I guess it could be. I have gotten it for guidance to the airport and if there are multiple planes in line for the approach.

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Would this be if ATC was considering issuing a side step in the case of parallel runway?

 

On VATSIM it's usually when ATC is considering forgetting about you then wanting you to land from a position 2 miles short of the runway at 3000ft.

 

I once decended on my own with the slope and was told that I wasn't cleared for that, so I climbed back to 3000ft. When they issued the clearance for the approach I declared a missed approach due to being too high instead of reading the clearance for approach back. When they asked for clarification about the go around I told them that the reason that I was too high was due to him telling me to climb back above glideslope and maintain 3000ft. He somehow didn't realise that 11 miles from a runway at 3000ft is on the 3°.

 

He then cleared me to climb to the missed approach altitude.

So I descended to the missed approach altitude of 2500ft and read back "Descending to 2500ft missed".

 

yea, I get a bit snippy sometimes, but you can't climb to an altitude below you, and sometimes stuff needs to be said.

 

 

In my opinion, the main reason you don't hit APP mode straight away is the possibility of false glideslope capture. False glideslope is a feature of how glideslopes function (has to do with some physics of electromagnetic radio broadcasting) and if you arm APP early, it may capture a ~1° glidepath which is well below where you should be. Making sure you don't arm APP before the proper approach fix prevents this procedurally.

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You press LOC then APP

 

If you press LOC and then intercept localizer at 4 miles from the runway at 3000ft, that APP button won't help much.

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Ahhhhh, one of the many situationally-dependent questions that pops up and people always give it in black and white.  Gotta love these.

 

Is it required to hit LOC before APP?

-No.

 

Is the autopilot more stable because you hit LOC first, let it intercept the LOC, and then hit APP?

-Not necessarily.  If you hit APP right at the point where it would intercept both LOC and GS, probably, but if you hit it farther out, in the normal scheme of things, no.

 

Is it improper to hit APP right off the bat?

-Depends on who you ask.  I'd say no, but those who have experienced a false glideslope before would likely disagree with me.  For what it's worth, you can't really get a false glideslope from below the normal glideslope anyway, just based on the mechanics of it all (it's one of the reasons why ATC brings you in below the GS for the approach).

 

 

 

TL;DR:

It's up to you.  You can press LOC until you capture the LOC and then APP, or you can just press APP right off the bat.

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I'm only a novice but on an ILS approach I think you just need to press APP to pickup the glideslope. I am not pressing the LOC button at all. APP seems to capture both the localiser and glideslope.

 

The thing is, an ILS approach doesn't begin with gs capture, once you are cleared, your vectors are to the ils by default. Always engage LOC first as the approach is precisely stabilized a lot further out and really there's no reason not to use it, unless you're flying a visual obviously.

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Ahhhhh, one of the many situationally-dependent questions that pops up and people always give it in black and white.  Gotta love these.

 

Is it required to hit LOC before APP?

-No.

 

Is the autopilot more stable because you hit LOC first, let it intercept the LOC, and then hit APP?

-Not necessarily.  If you hit APP right at the point where it would intercept both LOC and GS, probably, but if you hit it farther out, in the normal scheme of things, no.

 

Is it improper to hit APP right off the bat?

-Depends on who you ask.  I'd say no, but those who have experienced a false glideslope before would likely disagree with me.  For what it's worth, you can't really get a false glideslope from below the normal glideslope anyway, just based on the mechanics of it all (it's one of the reasons why ATC brings you in below the GS for the approach).

 

 

 

TL;DR:

It's up to you.  You can press LOC until you capture the LOC and then APP, or you can just press APP right off the bat.

thank for that man.. let me see how it works.. i am trying to connect the stars with the approach but my route doesnt give me that option to connect to the star i dont see that star under the apporach section so i clicked on one star and i clicked 28R and it was coming from the south the star but i am coming from the north so it got messed up.. How do you know how to connect with the star when your flying.

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How do you know how to connect with the star when your flying.

 

Don't.

 

When you select your approach, if it does not have an option for a transition that matches the last fix of the STAR, do not connect them.  It will likely have a vectors leg.  Leave that in there.  In the United States, many of the STARs are like this, and controllers sequence and descend aircraft on these vectors legs.  If you try to connect all of this stuff, you're going to end up high and fast in most situations.

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thank for that man.. let me see how it works.. i am trying to connect the stars with the approach but my route doesnt give me that option to connect to the star i dont see that star under the apporach section so i clicked on one star and i clicked 28R and it was coming from the south the star but i am coming from the north so it got messed up.. How do you know how to connect with the star when your flying.

 

Make sure everything is up to date. But atc will give you vectors to the runway, if that includes a star, you'll find out from them.

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TL;DR:

It's up to you.  You can press LOC until you capture the LOC and then APP, or you can just press APP right off the bat.

 

TL:DR - another Reddit fan !!!

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Don't.

 

When you select your approach, if it does not have an option for a transition that matches the last fix of the STAR, do not connect them.  It will likely have a vectors leg.  Leave that in there.  In the United States, many of the STARs are like this, and controllers sequence and descend aircraft on these vectors legs.  If you try to connect all of this stuff, you're going to end up high and fast in most situations.

So what your trying to say is that just click the ils 28R and let the plane fly o that loc and it will do all the work? In fsx atc it doesnt tell you if you should connect to the star. Just clarify with me on this. Thanks.

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So what your trying to say is that just click the ils 28R and let the plane fly o that loc and it will do all the work?

 

What I'm saying is that unless there is a prompt in the FMC to use the last waypoint of the STAR, do not attempt to connect the end of the STAR to the first fix of the approach.

 

As an example:

Flying into IAD on the BARIN1 arrival, it ends at MIXNN.  None of the approaches for IAD show a transition for MIXNN.  As such, you would never delete the discontinuity/vectors leg between the two.  A controller would give you vectors from this fix to the approach.  If you're not using a human controller, you will have to just use your best judgment to descend to the altitude listed on the LEGS page for the first fix of the approach, and use the heading selector to turn you toward the approach.

 

EDIT:

As an example of what you're looking for:

If you were to fly into CHO, your route would likely be CSN V140 WITTO.  While there is no STAR for this field, the concept is the same as having a STAR that dumps onto one of the arrivals.  If you look at the RNAV (GPS) Y Runway 21 approach, it has a transition off of WITTO.

 

This is the only time you connect the legs.

You only connect legs when the approach lists a transition off of your route, or off of the STAR.

 

 

In fsx atc it doesnt tell you if you should connect to the star.

 

It won't, and it never will.  FSX ATC can't handle this kind of thing, really.  Additionally, it's using nav data that's now almost a decade old.  The fixes won't have the right names.

 

If you're not going to use a human controller (VATSIM/IVAO/etc), I wouldn't use ATC at all, but that's just me.

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