Defining the MAP during a nonprecision approach

nosehair said:
No "regs" here, Mike. Only "made-up", "passed-down", "I was taught", school procedures that people think are regulatory.
No regulation says to use time. No regulation says you have to PT when you don't need to.
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Other than 91.175(a) of course. No, I understand - your view is that 91.175(a) actually says (bold/underlined language added

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(a) Instrument approaches to civil airports. Unless otherwise authorized by the FAA, when it is necessary to use an instrument approach to a civil airport, each person operating an aircraft must use those portions he likes from a standard instrument approach procedure prescribed in part 97 of this chapter for that airport. This paragraph does not apply to United States military aircraft.
==============================
I'll just disagree and leave it at that.
 
erice said:
Slight hijack, but ...

Regarding timing, are you allowed to use a wristwatch, stopwatch, or a portable timer to determine the time, or must you use the certified, panel clock or stopwatch? It's just that for GPS, you can only use handhelds for situational awareness--certified, panel-mounted GPS must be used for Instrument approaches.
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You can use a wristwatch or stop watch, you just have to have a clock that shows seconds(digital or analog) inside the airplane per 91.205(d)
 
Ajax BU said:
You can use a wristwatch or stop watch, you just have to have a clock that shows seconds(digital or analog) inside the airplane per 91.205(d)
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91.205

(a) General. Except as provided in paragraphs (c)(3) and (e) of this section, no person may operate a powered civil aircraft with a standard category U.S. airworthiness certificate in any operation described in paragraphs (b) through (f) of this section unless that aircraft contains the instruments and equipment specified in those paragraphs (or FAA-approved equivalents) for that type of operation, and those instruments and items of equipment are in operable condition.

(d)(6) A clock displaying hours, minutes, and seconds with a sweep-second pointer or digital presentation.

I've always taken the above to mean that all required equipment must be physically installed on the airplane. Now what you use is up to you, if you like your digital watch better, by all means use it, but I still think you've gotta have an approved clock onboard.
 
A150K said:
And anyone who has a $10,000 piece of equiptment in their avionics stack and does not use it (not talking about practice, but the real thing) is foolish. If the GPS and the time are saying different things, you bet I'm going with what the GPS says. I think most DPEs would agree with you too. They're looking for the sfaest pilot and to not use GPS or DME to help you out on a VOR approach in actual would not be the safest decision.
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......just don't rely on it while having your 4G phone around....:D
 
A150K said:
I've always taken the above to mean that all required equipment must be physically installed on the airplane. Now what you use is up to you, if you like your digital watch better, by all means use it, but I still think you've gotta have an approved clock onboard.
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That's the point I was trying to get across, if I would have used the word "installed" it would have cleared it up a bit. The installed clock also has to be operational for the flight to be legal, you can't just decide to use your wrist watch if it's not working.
 
I always thought legally it couldn't just be any clock, but the clock installed per the aircrafts type certificate. Could be wrong.
 
According to AIM Section 1-1-19, Subsection C (Use of FPS for IFR Oceanic, Domestic Enroute, and Terminal Area Operations), number 3 says: (cliff notes)

The GPS Approach Overlay Program can only be used if the IAP has "or GPS" in the title. If it does not have "or GPS" in the title, the database may contain information about the nonoverlay approach procedure that is intended to be used for enhanced positional orientation, generally providing a map, while flying these approaches using conventional NAVAIDS. These approaches should not be confused with a GPS overlay approach.

So in this case, you would still fly the approach based off of VOR and time for the missed approach point. The GPS can only be used for positional awareness and not to determine the MAP.
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Actually the regs say "tuned in and identified". Regardless, it is what regulations do not say which makes it legal. Yes you may use the IFR certified GPS fix for MAP to identify the MAP instead of time. You are not legally required to back it up with the timer either. Call me renegade but I never use the timer. Why, because I have a much more useful and accurate instrument for that purpouse and the more attention I can direct at the approach the better. This also reduces the scan, enabling more focus. What are the chances of your GPS failing from FAF to MAP on these very few approaches that exist these days anyway with our excellent reliability. Any other approach you would have to go missed anyway w/o DME or cross radial. The same thing can be said for using the #2 VOR to backup cross radial fixes or to back up final. It is much more wise to back up final and use the GPS by itself to identify these fixes for step down or whatever. After having my share of needles gone wild in the soup I am a firm advocate of having 3 pieces of info to track final on and that would be the pink line, the #1 and the #2 VOR's if able. Also as long as you have at least one instrument tuned in and identified to the appropriate navaid (for other than GPS approaches) there is nothing that says you cannot have your primary in GPS mode. Of course prudence would dictate that you base your final course corrections based on the ground based navaid if it has a narrower course. As an example you have a VOR approach into an airport (navaid not based on the airport). By putting the GPS in .3nm manually you will have far superior course guidance when nearing the MAP than only using the VOR. This is legal and I believe safer than just using the VOR, especially since some approaches like this can incur VHF interferance and produce a wavy needle at times.

If you loose the GPS on the approach it is usually much better to go missed anyway unless you pre-briefed the approach for non-gps.

So to recap: IT IS LEGAL!
 
denver said:
Yes you may use the IFR certified GPS fix for MAP to identify the MAP instead of time.
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I don't think anyone in this thread suggested for a moment that using a GPS or DME fix identified as MAP on an IFR approach chart was not proper :confused: But I may be misunderstanding what you are saying, so this question might help: what is the "IFR certified GPS fix for MAP" on the chart linked to in the original post?
http://204.108.4.16/d-tpp/1104/05540VA.PDF
 
Yes on this approach in the GPS database there should be a fix representing the MAP as well as the VOR. I understood the question and it is legal to use the MA(runway whatever) to identify the MAP. If it is in the database and represented as MA (this stands for missed approach) you may use it as the sole means of identification.
 
denver said:
Yes on this approach in the GPS database there should be a fix representing the MAP as well as the VOR. I understood the question and it is legal to use the MA(runway whatever) to identify the MAP. If it is in the database and represented as MA (this stands for missed approach) you may use it as the sole means of identification.
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The FAA's term for defining the MAP on a non-precision approach, it states that if there is a 5 letter (ABCDE) ID for a fix or a runway # and M (RW34M), you can use that as the MAWP.

In AIM 1-1-19, subpart J (waypoints), number 4, the MAWP may have a 5 letter ident, or RW##. If the MAWP is not located at the threshold, it will have a a 5 letter ident. Since this approach does not have an ident for the MAWP (not located on the threshold), one shouldn't show up in the database and you wouldn't have any clue how to ident the MAWP other than time.

Saying it "should be" there is like saying the FAA "should" make it clear as to this subject. However, you don't know for a fact that this approach does or does not have a MAWP in the database...a Garmin G1000/530/430 might have it, but what about the KLN-89B in my 310? When I get a chance, I'll go check.

IF there is a RW##M in the datebase, by all means, use it! If there's not a RW##M or a 5 letter ident, then the "FAA correct" way would be to use time. (which is original question at hand).

With this being a VOR-A (circling approach), I'm going to lean towards there not being a RW##M in the approach on the GPS, mainly because there's not a runway that you're shooting this approach specifically to.
 
denver said:
Yes on this approach in the GPS database there should be a fix representing the MAP as well as the VOR. I understood the question and it is legal to use the MA(runway whatever) to identify the MAP. If it is in the database and represented as MA (this stands for missed approach) you may use it as the sole means of identification.
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Thank you. I'd appreciate a FAA publication (regulatory or not) reference that supports your opinion.
 
With this being a VOR-A (circling approach), I'm going to lean towards there not being a RW##M in the approach on the GPS, mainly because there's not a runway that you're shooting this approach specifically to.
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I would be willing to be that if this approach is in the database at all for any GPS it will have 2 waypoints, the VOR and the RW##. What would be the point in having a one waypoint approach in there, you could not even use it for situational awareness. I have flown many approaches with a KLN94 like this and there has allways been a RW## waypoint or a 5 letter. That does not mean that this one is in the database though. When I am down at the 421 again I will take a look on this one approach to see for sure but I would be willing to bet that it is in there and since you need at least 2 waypoints to define a GPS approach I bet the MAWP is in there as well.

As far as FAA publications or a ref. In many instances it is what is NOT stated that makes it legal. I do not really agree with the way they do it but in law in every field this is often taken in interpretation for grey areas.

Hope this helps.
 
denver said:
As far as FAA publications or a ref. In many instances it is what is NOT stated that makes it legal. I do not really agree with the way they do it but in law in every field this is often taken in interpretation for grey areas.

Hope this helps.
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Not much.

Yes, in many instances what is not stated makes something legal. But given what has been cited by others in support of a timing requirement, unless I could point to something to the contrary, I'd personally conclude that this is a question without a clear answer, rather than make the bald statement that it's legal.

Off course, I also think that, practically speaking, and from a safety standpoint, it's a complete non-issue to begin with.
 
SurferLucas said:
the "FAA correct" way would be to use time.
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Bear in mind that your reference for this technique is the Instrument Flying Handbook which is an Advisory Circular.

Advisory Circulars give guidance on a way, ( a way, not the only way) to comply with regulations.
Timing is used extensively in training, and for good cause, but like checklists, timing is not a regulatory requirement.
 
How is the answer not clear? Regulations must be explicit in their delivery. It is not to often you see a regulation that says you may do something. Unless we are talking about exception paragraphs, regulations state what you must, or cannot do. If they don't say you cannot do it, then you can do it. If we had a FAR/AIM that listed not only what you cannot do but what also you can do it would cover several volumes. If it's not clear at this point I think you are over thinking the issue. You must not "go on what others are saying" and follow the herd. No offense with that but there are many mis interpretations by people in FAA regulations and it can be very contaigouse as it spreads around on the internet. Sort of like "It is illegal to fly strait in approaches at uncontrolled fields". If it does not say it in the reg's it's fair game as far as FAA goes. If you are that concerned about it then get guidance from your local FSDO not what everyone else on this forum says.

And how many times could I list the "FAA correct" way as the best way NOT to do something, at least a few.
 
denver said:
If you are that concerned about it then get guidance from your local FSDO not what everyone else on this forum says.
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First, as I've said, I'm not concerned with the answer. Second, If I really was concerned, why would I get guidance from the single worst place - the local FSDO where the answer could depend on who is on duty that day? (Ever been with two inspectors who disagreed with each other about whether certain conduct violated a rule?)

As far as I can tell, this has been primarily an academic discussion, with most people saying in effect, "Of course I'd use the most reliable source to tell me where the MAP was. I'm just wondering whether there is a rule on it." If you don't want to join in the spirit of that kind of discussion, you're welcome not to.

If it does not say it in the reg's it's fair game as far as FAA goes.
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As a general rule, not really. There are hundreds of FAA Chief Counsel interpretations, some of which either permit or don't permit something based on interpretation and even expansion of the strict wording of the FAR.

The reg says,

==============================
Instrument approaches to civil airports. Unless otherwise authorized by the FAA, when it is necessary to use an instrument approach to a civil airport, each person operating an aircraft must use a standard instrument approach procedure prescribed in part 97 of this chapter for that airport. This paragraph does not apply to United States military aircraft.
==============================

So, when the timing box is on the plate and there is no DME fix, GPS waypoint, or intersection that identified the MAP, is the timing box part of the "standard instrument approach procedure prescribed in part 97 of this chapter for that airport" that must be followed by the pilot? Don't think it can be expanded that way? This is the same rule that led the Chief Counsel's office (and the AIM, although one is "non-regulatory") to say that a depicted PT mist be followed regardless of whether the pilot thinks it's necessary to reverse course.
 
Well dude, basically it's all legal untill you crash so fly safe and don't worry to much about the minutia. Thank god we still have at least one industry left where we police ourselves for the most part.
 
Pretty much agree except you don't have to crash. All you have to do is cause a problem for the system. Either is highly unlikely in this scenario.
 
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