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Guest Jet Ranger

"Established on Localizer"

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can some just briefly explain how do I know when Im established on the localizer.

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Basically when your AP or you yourself intercept the localizer. Usually, in a Boeing (or an Airbus), you are either in NAV or HDG mode, with localizer mode armed. When the aircraft senses the localizer, it begins its last turn to aligh itself. When that is complete, usually you are in a LOC mode (=established on the loc).

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The instruction is usually "maintain X thousand feet until established on the localiser"So in something less sophisticated, and assuming the runway has a glidesope, you must maintain the assigned altitude until you are lined up on the runway heading and have intercepted the glideslope.You can then descend along the glidescope to the runway.Aircraft differ, but there will be some sort of horizontal indicator to show when you are lined up on the runway and then a needle or something which drops downwards as you come to the glideslope. When it hits the "horizon" you may descend.Here's one I prepared earlier: the little green triangle at the bottom of the display shows I'm lined up on the runway at 160 degrees and the little arrowhead level with horizon shows I'm on the glideslope.Miracles never cease!http://forums.avsim.net/user_files/187409.zip

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I believe you are "established on the localizer" when you are flying the inbound course and within +/- 1/2 dot of deviation.scott s..

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Wow, you guys would fail the Instrument knowledge course:Established on the localiser means that you are:1) tuned to the localiser frequency for the desinated runway (not to be confused with the glideslope). Once you have tuned to the LOC frequency and the vertical needle becomes centered and you are showing a similar heading on your HSI (with wind correction angle applied) you are established on the localizer.Do NOT confuse the localizer with the glideslope which is the horizontal bar. Both the localizer and the glideslope together form the ILS. ATC is not concerned with the glideslope indicator because in most cases you don't need it to land since most airports have a standard 3.0 glideslope whether you are flying the needles or not. From an glideslope standpoint you can be on or ABOVE the glideslope on approach (never below). You don't even need to follow the glidelope needle and can transition to visual and follow the VASI or PAPI in (white you're alright , red you're dead).So..To make a long story short. Once you are on an intercept course to the runway heading (for instance you are approaching runway 35R from heading 310). Your LOC needle will be deflected to the left and as you come within 10 degrees of 350 the needle will begin to move to the right (you have 20 degrees of deflection). You should now be banking to center the LOC needle on HSI 350 (mag var not withstanding) and aim to have the needle centered as the same time you roll out of your bank at heading 350. You are heading in on the runway heading and your LOC is centered on the runway heading.You are now established on the LOC. Contact tower...good day :-)HTH,Mike T.

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Mike T is spot on.Practically though, to report "localiser established" we normally wait until the localiser mode changes from armed to active. In Airbus speak that means when we go from Loc blue to Loc green. If it's being hand flown we normally report localiser established when the localiser becomes active (i.e. the little magenta diamond starts moving).Not strictly correct but practically what we do.Hope this helps,Ian

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There is an exact definition from the FAA. It's been a little while since I saw it, but I believe it is approximately the following:Within 1 dot deflection of localizer AND within 10 degrees of the final heading.As others have pointed out, practically it is simply once you've interecepted and are tracking the ILS localizer. Remember, that you can't descend on a G/S signal before being established on the localizer. If you do, you are not certain of obstacle avoidance and you could be descending on a false G/S echo that will lead you to someplace other than the runway threshold.

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"could be descending on a false G/S echo"...Actually, there is no such thing as a G/S echo :-). To verify that you are have tuned to the right ILS approach simply switch from COMM to NAV on your radio and you will hear the ILS approach morse code or verbal designation. The morse code for the ILS is printed on your approach chart so simply match up the dots and dashes to what you hear, and, if its spoken to you verbally then even better.And YES you CAN descend before being established on the LOC, regardless of your place on the glideslope because you will be approaching the ILS with the GS above you (never below you). ATC will bring you down to whatever the FAF altitude is regardless of what your your G/S is doing. If you are flying VFR to an ILS approach then simply look on your sectional chart which will tell you the minimum altitude you need to maintain to clear every object in each quadrangle of the chart. At no less than 5 miles out you should be established on a decending G/S.HTH,Mike T.

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>Actually, there is no such thing as a G/S echo :-). There most definitnely is. It is not modeled in the FS world, but it is perfectly real in actual aviation. It has nothing to do with tuning the wrong ILS, but rather the G/S signal bouncing off of surrounding terrain, creating an erronous direction indication relative to the refleciton point and not the runway threshold.And in part 121 operations, you can not descend on G/S before LOC capture...period. If you do not intercept the LOC and the G/S is falling below, you must abort the approach since you cannot interecept from above (as you noted). There is a difference between descending ont he localizer and descending to the ATC directed MVA which is in fact ok. If you'd like, you may descend on the G/S signal to your ATC assigned altitude, but if you're not established on the localizer by that point, you must level off and capture the localizer before descending further. This obviously creates problems if you go full deflection above G/S since you can not intercept G/S from above. Part 91 does make some allowances outside of this.

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Umm, no it is not a factor in real world aviation since there are only a handful of stories with this example and it is NOT terrain that's messing up the signal, it is obstructions within the 'ILS protected area' or an outright ILS failure. You have a better chance of getting hit by a meteor on approach. If terrain were a factor in radio signals it would ALSO mess up the LOC, VORs, marker beacons and everything else...not just the glideslope.Thanks for the adhoc FAR lesson (I just finished my bi-annual this past weekend though) :-) but what you quoted is exactly what I said in my previous post :-). Which goes back to the original point, establish yourself on the LOC, capture the GS from beneath and you'll be okay.I'm done.Mike T.

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>Umm, no it is not a factor in real world aviation since there>are only a handful of stories with this example and it is NOT>terrain that's messing up the signal, it is obstructions>within the 'ILS protected area' or an outright ILS failure. >You have a better chance of getting hit by a meteor on>approach. If terrain were a factor in radio signals it would>ALSO mess up the LOC, VORs, marker beacons and everything>else...not just the glideslope.>>Thanks for the adhoc FAR lesson (I just finished my bi-annual>this past weekend though) :-) but what you quoted is exactly>what I said in my previous post :-). Which goes back to the>original point, establish yourself on the LOC, capture the GS>from beneath and you'll be okay.>>I'm done.>>Mike T.>>The false glideslope is caused by the signal reflection from the ground immediately in front of the antenna. All glideslope antennas have some type of ground around it. If you are high enough, you will receive a false GS signal. That is why you always need to verify your GS intercept altitude crossing the marker. I have seen it. But I have not been hit by a meteor yet. It is something that you should not have to see if the controller is doing his job correctly and you are complying with his instructions correctly. If you join on the ILS close in and high, as can happen when the controller cuts corners for a visual approach, a false GS receipt is a distinct possibility.Hopefully, I'm reading your post wrong, but please explain to me how beginning a descent before being established on the localizer is not a violation of 91.175(i).

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>Hopefully, I'm reading your post wrong, but please explain to>me how beginning a descent before being established on the>localizer is not a violation of 91.175(i).My interpretation per FAR stated is that you are exactly right...you may never descend on G/S before being established on LOC AND recieving runway approach clearance. However, my experience is that this is is often overlooked because many part 91 operators (i.e. general aviation private pilots) fly VFR supported by instruments (even when they file IFR). As such, they will often just terminate IFR on approach and continue with the visual, which does not have this restriction. Part 121 operators on the otherhand tend to follow the opposite, flying IFR, supported by visual reference. I have never seen a part 121 operator break this rule unless they're already cleared for a visual approach, and even then they usually fly the ILS signal for backup. And thanks for clarifying where the echo is coming from. I should have mentioned that I was not refering to it bouncing off a mountain or a downtown skyscraper. At one point, we calculated this as an excercise in signal processing and the maximum points for this echo were somewhere on the order of +/- 30 degrees laterally and 9 degrees vertically, hence the reason for suspiscion if you're high or not established.>And YES you CAN descend before being established on the LOC,>regardless of your place on the glideslope.My apologies if I misunderstood you, but this was in response to me saying that you can not descend on G/S before localizer intercept. I had assumed you were saying this is incorrect...which it is not.

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>>Hopefully, I'm reading your post wrong, but please explain>to>>me how beginning a descent before being established on the>>localizer is not a violation of 91.175(i).>>My interpretation per FAR stated is that you are exactly>right...you may never descend on G/S before being established>on LOC AND recieving runway approach clearance. However, my>experience is that this is is often overlooked because many>part 91 operators (i.e. general aviation private pilots) fly>VFR supported by instruments (even when they file IFR). As>such, they will often just terminate IFR on approach and>continue with the visual, which does not have this>restriction. Part 121 operators on the otherhand tend to>follow the opposite, flying IFR, supported by visual>reference. I have never seen a part 121 operator break this>rule unless they're already cleared for a visual approach, and>even then they usually fly the ILS signal for backup. >This is not a 91 vs 121 thing. This is VFR vs IFR. If you're flying VFR, you can fly whatever altitude you want as long as no cows get scared and no holes are punched in clouds. Nothing in 91.175 applies. You guys are mixing VFR and IFR into one pot in this discussion.>>And YES you CAN descend before being established on the LOC,>>regardless of your place on the glideslope.>>My apologies if I misunderstood you, but this was in response>to me saying that you can not descend on G/S before localizer>intercept. I had assumed you were saying this is>incorrect...which it is not. I'm not Mike T.

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>This is not a 91 vs 121 thing. This is VFR vs IFR. If you're>flying VFR, you can fly whatever altitude you want as long as>no cows get scared and no holes are punched in clouds. >Nothing in 91.175 applies. You guys are mixing VFR and IFR>into one pot in this discussion.I know this is different. I am just noting it, because I have seen this "violated" by part 91 flyers before and I think this is how they get away with it. I've never seen part 121 violate it. In the end, I was just trying to say I think the way some private pilots get away with it is not because part 91 is more leniant, but because they are more ready to switch to VFR over IFR. Per FAR, no pilot flying an ILS approach should be descending on the G/S before getting on the localizer.And I know you're not Mike T. My apologies for the confusion, I was just trying to condense responses into one post.

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>>I know this is different. I am just noting it, because I have>seen this "violated" by part 91 flyers before and I think this>is how they get away with it. I've never seen part 121>violate it. In the end, I was just trying to say I think the>way some private pilots get away with it is not because part>91 is more leniant, but because they are more ready to switch>to VFR over IFR. Per FAR, no pilot flying an ILS approach>should be descending on the G/S before getting on the>localizer.>If you're flying with people who do this without cancelling IFR, you should say something to them. The FAA can violate anybody that is in the plane that holds a pilot's license. Even if they're sitting in the back seat. Not to mention you don't know what you'll hit if you do start descending before being established. As long as you've cancelled IFR and continuing VFR in VMC, you can do whatever you want.

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