Question about IFR approaches

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Past examiner also said why make it harder than it has to. Meaning if you have DME and it can be used don't bother to time less cockpit workload

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If the DME is off the LOC, then I could see that. If it's off the VOR or a GPS, then I would still start the timer. You can lose the signal on the VOR or have a RAIM failure on the GPS. Then again, I'm paranoid. I really don't see hitting a button as a huge increase in my cockpit workload.

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What if you have the DME off the GPS, would you still time then?

I don't, and the examiners don't have a problem with that.
 
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Okay relating to my last post I am guessing it is all gray area.

[/ QUOTE ] Well, sort of. The MAP on any approach chart, and the "official" way to determine it is =always= well defined. It might be an on-airport navaid, a DME fix, a waypoint, or time.

So for example, take a look at the BAF ILS Runway 20 at http://naco.faa.gov/d-tpp/0412/00446I20.PDF

The non-precision MAP may be officially identified in one of two ways. If you have DME, you can use 1.1 DME off the BAF VOR. If not, you use timing from the outer marker . Notice that the middle marker is =not= co-located with the non-precision MAP.

The "grey" comes in because overall situational awareness comes in many packages, and all of them are legitimate to use to supplement the "official" method. Let's assume you're flying that BAF approach without DME.

So what if that MM isn't the MAP?If you're equipped with a marker beacon, isn't that tenth of a mile difference pretty inconsequential, especially when you consider that time is based on ground speed so is almost always an estimate in the real world?

For that matter, how about the 160° Radial off CTR? The missed approach procedure has you flying directly to it after the initial climb, so you probably already have it tuned in. Why not set the obs initially to 340° to help locate the MAP, knowing that you'll only have to twist it another 10° or so to go directly to it when you make the turn?

Or how about that nice VFR-only panel or handheld GPS that's been so reliable?
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One last Question
So the MAP on an ILS is the DA (or do they call it DH these days) even if there is a MM?

[/ QUOTE ]Yes. The MAP for an ILS is where you hit DA while on the glideslope. That's the whole idea. The MM =may= be near DA, but it might not - it's actually placed with reference to the runway threshold, but it's usually close enough.
 
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What if you have the DME off the GPS, would you still time then?

I don't, and the examiners don't have a problem with that.

[/ QUOTE ]I wouldn't expect an examiner to have a problem either way, so long as you don't miss hitting the timer when you have to.

I, and from some of the other posts here, others would still hit the timer.

You may be slightly missing our point. We'd probably hit the timer r even if the approach doesn't have =any= timing component listed. Not because it's needed for anything on that approach, but strictly as part of standard operating procedure when crossing an FAF.

It just means one less thing to forget and as kellwolf put it, "I really don't see hitting a button as a huge increase in my cockpit workload."

I remember a discussion about this on another board. An instrument student was having a common problem - forgetting to hit the timer on timed approaches. Wanted some tips on how to remember. I suggested hitting the timer on all approaches, which I hear solved the problem completely.
 
Great discussion.

I think it is essential to hit the time inbound. Yes, if you have a GPS you will be able to determine the MAP with DME but if you don't have and updated database, or RAIM, you can't. If you lose glideslope you can continue along without it using the LOC MDA but the biggest question is "how do you identify the MAP?" If you don't have DME or the IAP doesn't use DME to determine the MAP you need time, it is the only way to know when to go missed. As the FAR's say, you can climb before the missed but you can't legally turn before the MAP. And knowing that I am not guaranteed obstruction clearance after the MAP I know I have to start the MAP right at the MAP. Additionally, using ATC to determine where to from the MAP by requesting vectors assumes that you are in a radar environment, you are above the MVA, and you haven't gone to CTAF in a class E airspace, or class G airspace to the ground, environment. All IFR aircraft have to have a clock. Why not use it?

With regards to the MAP being colocated with a MM, this not the case out here in the West. I can name a handleful of IAPs locally that dont' are LOC only and ILS that don't have a MM. Do not rely on a MM to determine a MAP!

BTW, the FAA orginally called the DH the DH and then Jepp came along and stated it was flawed because it was based on a barometric attitude and therefore it wasnt' truly the height above the ground it was a DA. That is why on all Jepp plates it is labeled as the DA(H). Trivia, but interesting
 
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What if you have the DME off the GPS, would you still time then?

I don't, and the examiners don't have a problem with that.

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Yep. Just in case I lose RAIM coverage or any other screwy glitches. And as other people have said, it's ingrained in my head so much at this point to hit the timer, I might have to make a concious effort NOT to start it. I'm not saying it's wrong NOT to hit the timer, it's just a personal preference of mine.
 
I agree with Ophir, it is a good habit to always start the time whether you're on a precision or non-precision approach.

Perhaps you wonder about the significance of the time check on the precision approach.....
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Of course if you get a flag for your glide-slope during the approach it becomes a non-precision approach, but when will you go missed after reaching your MDA? Unless there is a DME on the ILS or the airport you are approaching you have no real way to judge when to go missed on a localizer approach only. (Maybe the Middle marker however not every ILS has a MM).

Here is an example of such an approach, if you lost your GP and continued in as a loc approach, when would you go missed?
Titusville ILS 36
 
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With regards to the MAP being colocated with a MM, this not the case out here in the West. I can name a handleful of IAPs locally that dont' are LOC only and ILS that don't have a MM. Do not rely on a MM to determine a MAP!

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Agree with you on that If im not mistaken they are getting rid of the MM. I just updated my Jepps two nights ago with Cedar City's MM being removed
 
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