Instruments required for an ILS

[E_Dawg]

1)Are marker beacons required when shooting an ILS? I know they're one of the fundamental components of an ILS but let's say you're in a crap plane with no beacon lights (and in a no radar environment so ASR or PAR is not an option; nor is there any other way of identifing the fix).

2)Also what happens if the MM is inop and you have no compass locator in a non radar environment?


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Here's what I think:
1)Yes they are required for an ILS approach.
2)You can still shoot the approach with the original published minimums.

If someone could correct or verify that'd be awesome; thanks

[MikeD]

[ QUOTE ]
1)Are marker beacons required when shooting an ILS? I know they're one of the fundamental components of an ILS but let's say you're in a crap plane with no beacon lights (and in a no radar environment so ASR or PAR is not an option; nor is there any other way of identifing the fix).

2)Also what happens if the MM is inop and you have no compass locator in a non radar environment?


----


Here's what I think:
1)Yes they are required for an ILS approach.
2)You can still shoot the approach with the original published minimums.

If someone could correct or verify that'd be awesome; thanks

[/ QUOTE ]

No, marker beacons aren't required for ILS IAPs; in fact, there's a number of them (Cat I) that don't have them. Remember, on an ILS, there's no FAF (the Final Approach Fix is only for the LOC, or non-precision portion of the IAP); and the Decision Height is defined by where the glideslope intersects an MSL altitude (Cat I).

With an inop MM, you shoot the IAP normally. Remember, the MM is an aid only, NOT a definition of MAP. DH is defined as I described above, while MAP for a non-precision IAP is defined by an MDA and a DME, or timing, or in the case of a terminal approach, crossing the NAVAID itself.

So far as inop items go that affect the approach itself, normally any approach lighting systems (ALSF, SSLAR, etc) that are inop will tend to raise the viz requirements for that approach. IAP books have an "inoperative components" table that covers this, along with any caveats in the remarks section of the approach plate itself.

MD

[mikek123]

[ QUOTE ]
2)Also what happens if the MM is inop and you have no compass locator in a non radar environment?


[/ QUOTE ]

You cany fly a normal Cat 1 approach with the MM inop. Many airports don't even have a MM. DAB is one of them. I have flown few approaches that actually have a MM.

[Doug Taylor]

Actually, just a minor note: Some consider the FAF on an ILS as being on the LOC and intercepting the GS at GS intercept altitude.

But that might just be a DL definition, I'm far too lazy to check the FARS.

IUATATICBCFAM!
(I used all the acronyms that I could but couldn't find any more!)

[Eagle]

[ QUOTE ]
No, marker beacons aren't required for ILS

[/ QUOTE ]

which is a good thing as *koff koff* sometimes people forget to turn them on

[Doug Taylor]

Heck, I usually only have mine on for when ATL says "turn left 250 degrees at the marker, cleared for takeoff" or when we're shooting a balls to the wall Cat II or III approach.

[E_Dawg]

OK thanks.... so if it's the LOC you need the beacons (assuming no other way of identification) and if it's the ILS you don't.

[ready2fly]

That's the way I understand it - that if it's an ILS, the beacon is not a necessity and the FAF would be the intercept altitude.

Of course - the plane I'll be doing my checkride in DOES have an ADF and I have been drilled - ad nausiam - about turning the thing on and tuning it in.

Good luck, Ed... you ready?

[MikeD]

[ QUOTE ]
That's the way I understand it - that if it's an ILS, the beacon is not a necessity and the FAF would be the intercept altitude.

Of course - the plane I'll be doing my checkride in DOES have an ADF and I have been drilled - ad nausiam - about turning the thing on and tuning it in.

Good luck, Ed... you ready?

[/ QUOTE ]

Like I said in my first post, marker beacons aren't required for ILS or LOC IAPs, they're merely an approach aid. LOCs can use RADAR, or DME, for positioning, or even ADF bearings; of course with having the minimum equipment required.

MD

[ready2fly]

[ QUOTE ]
Like I said in my first post, marker beacons aren't required for ILS or LOC IAPs, they're merely an approach aid.

[/ QUOTE ]

And like Bartles & James.... we thank you for your support.

R2F

[E_Dawg]

[ QUOTE ]
Good luck, Ed... you ready?

[/ QUOTE ]

Hell yeah I'm ready!!
Thanks!

The only other note about the marker beacons is that regardless of whether or not it's required, it's still a good idea to have them; reason being what if the GS goes out, turning your precision approach into a non precision one. That's the only place you'll have to start the time and the only way you'll know when to go missed in a no radar environment (far fetched but still).

[MikeD]

[ QUOTE ]
[
The only other note about the marker beacons is that regardless of whether or not it's required, it's still a good idea to have them; reason being what if the GS goes out, turning your precision approach into a non precision one. That's the only place you'll have to start the time and the only way you'll know when to go missed in a no radar environment (far fetched but still).

[/ QUOTE ]

Agree it's a good aid to have. But keep in mind that with most ILS approaches, if you lose GS, you now simply comply with the DME stepdown fixes and have an MDA. Of course, if you're talking about losing the GS when inside the FAF (and assuming you didn't hack the clock AND the LOC approach MAP is identified by timing) then I see where you're coming from and it would indeed be plausible.

MD

[Ophir]

Here is a good question I have been trying to figure out:

I am flying a C182 here with a KLN 94 with a MFD. When I am vectored to the FAF how do I read DME on it? Or another way of saying the same thing is, while flying the ILS/DME 35 approach into SLC the DME fixes are not off the localizer they are off TCH VOR ( about 5NM from the TDZ). If you go to the INT 1 page on the GPS you will see the next intesection DME, but while flying the approach that intersection is not TCH. So how to find your intersections? I know the obvious one and that is with the MFD, but what if you didn't have one?

Sorry if that question is as clear milk.

[EatSleepFly]

Put the VOR into the GPS. You dont need the GPS for an ILS approach anyways.

[Ophir]

So what qualifies as you DME then?

When you select an approach in the KLN you cannot modify it, you cannot add a waypoint at the end of the approach.

[EatSleepFly]

I'm not quite sure I get what your asking, but...

If you're flying an ILS, and you need DME info. from a VOR, all you have to do is put XYZ VOR into the GPS and it will give you distance to that VOR. Thats your DME.

[A300Capt]

You're going to have to back it up with raw data DME by tuning in the TCH VOR.

When the GPS displayed waypoint DME counts down and reads 0.0 passing over KERNN (FAF), the raw data VOR DME will read 10.2. The approach plate does say "DME required".

We always back up FMS/GPS waypoints with raw data DME if required and depicted on the approach chart.

[Ophir]

So there is no way to load the approach and then monitor the DME off TCH while the GPS files a coupled approach?


But before I forget, thanks A300

[iceman21]

I may be off the scope here but, a GPS does not read DME distance, it reads actual distance. DME has slant range error, therefore the GPS and DME may never read the same distance. Not sure if this is relevant to the last few posts but no need in confusing everyone and giving everyone the thought that just because you have a GPS you now have DME, which is not the case.

[Ophir]

You are right Ice but when you are flying an instrument approach, and you don't have a DME but you have a approach certified GPS, the FAA allows you fly "DME Required" approaches so long as you RAIM hasn't gone bad.

The big question is, if you don't have an MFD, how to monitor your DME? WIth the MFD you can sort of cheap because you will know if you are over, before or after an intersection. But is this really cheating or is that how the FAA intended you to use it?

[EatSleepFly]

I still dont think I'm understanding what you're asking. If you want to fly an ILS, and you need DME data, put the VOR in the GPS. That will give you distance, and that counts as DME. You do not need the GPS on an ILS approach. Its really quite simple. If you don't have DME or a GPS, you cant fly the approach if it says "DME REQUIRED".

[A300Capt]

[ QUOTE ]
You do not need the GPS on an ILS approach. Its really quite simple.

[/ QUOTE ]

Yea, I think what he wants to do is fly the ILS while using the moving map of the GPS and the waypoints depicted for reference, while at the same time show real DME from the TCH VOR.

I don't know if some GA model GPS's have a page or setting where a particular navaid can be tuned in to get real DME distances much like we can do with FMC equipped aircraft?

I think, if your GPS is so equipped, would be to go to the HSI mode and type in the TCH identifier or freq and then flip between the waypoints page for the approach and HSI page for DME from TCH.

Confused yet?

[Ophir]

First, what I am interested is while flying a GPS couple approach. So while you are flying coupled approach you cannot tune in the VOR on the GPS or you disengage the AP.

So A300, what you are saying is possible but it just doesn't seem right, to flip between two pages while on approach. What I was getting at too was "does the FAA feel this is appropriate?"

[ananoman]

What you are saying does not make any sense. You cannot fly a 'GPS Coupled Approach' on an ILS, you would have to couple the AP to the localizer/glide slope to fly a coupled ILS. Otherwise you will just follow the localizer course in the GPS database. You are not supposed to do this. The ILS approaches in the GPS database are for sitauational awareness only. You are not even supposed to fly a localizer approach this way, even though it would be possible to do so.

To fly a coupled approach with an autopilot you should tune and ID the localizer and couple the autopilot to that. To get DME info you have two choices. In the GPS you can either pick the navaid that is depicted on the approach plate for DME, or load the ILS approach from the GPS database. If you pick the approach from the GPS database it will give distance to the fixes listed on the plate, then cycle to the next fix. For instance if you are on the localizer the GPS will show how far you are from the outermarker, then the mm, then the runway threshold. If you pick the navaid that is used on the plate you would pick the VOR or the localizer, etc. Then you will have DME just as it is depicted.

When I am flying an ILS approach I prefer to use the navaid depicted on the plate. It is less confusing and it is easier to just put in 'Direct' to the navaid than load an approach. This also has the advantage of not having the GPS go into suspend mode after you go missed like it does after you cross the runway threshold if you actually loaded the approach.

[Ophir]

Good tip.

You are right about the coupled approach. What I was thinking of was the last time I shot a coupled approach I was following the DME arc in on the GPS and one established on the localizer the AP arms for the glideslope. I will have to check out this week. I will play with switching to tracking the VOR for the DME on the GPS. But it still won't display DME from a VOR while selecting an approach on the GPS. I know what you are saying is that you should select an approach, just put in the FAF intesection and the final waypoint as the VOR and you will get it. But it still seems strange to me that you cannot monitor DME while on final after selecting the approach to be loaded in the GPS.