I should know this...

c172captain

c172captain

Well-Known Member
On NOS Approach Plates, the maltese cross indicates the final approach fix on non-precision approaches while the Glide Slope Intercept is the final approach fix for precision approaches (so far so good, I think).

My question: When might you not/what is the significance of NOT having a maltese cross on an instrument approach profile?

My buddy said that the lack of the maltese cross (on a non-precision) means that there is no final approach fix (FAF), why is this important?
 
BajtheJino said:
One would be when the Procedure turn is the FAF.
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'Zactly.

To put it another way, as soon as you're established inbound following the PT you can descend to the MDA.

Or, I suppose, if you're being vectored on, once you're established inbound and within the "remain within x miles" circle on the chart you can go down to the MDA.
 
woutlaw said:
Or, I suppose, if you're being vectored on, once you're established inbound and within the "remain within x miles" circle on the chart you can go down to the MDA.
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...legally. I had a check instructor on my case because I descended 'too early'. I was correct per the rules, but he told me to visualize my own FAF so I don't end up low for an extended period of time (fair enough).
 
Adler said:
Do you know that for sure, or are you just speculating. At KBTL we have a VOR 23 (with a vor on the field) http://204.108.4.16/d-tpp/0901/00041VTG23.PDF that has a FAF; but for the VOR 31, there is no FAF http://204.108.4.16/d-tpp/0901/00041VTG31.PDF
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I know for sure that one of the times you wouldn't have an FAF would be an approach with the VOR (or NDB) on the field. If you have a cross radial or DME defining the FAF, that's going to be a different animal.

That doesn't change the fact that an approach to a VOR or NDB on the field could (and in many cases...) be without an FAF.

-mini
 
Adler said:
...legally. I had a check instructor on my case because I descended 'too early'. I was correct per the rules, but he told me to visualize my own FAF so I don't end up low for an extended period of time (fair enough).
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Thats the worst advice I've ever heard. There is absolutely nothing wrong with descending the first moment you can. Theres no towers or obstructions as long as you remain on the approach. Remember, someone has already checked this out to be sure! There have been many times I've shot a VOR approach to a certain airport that if I hadn't got down as soon as I could I wouldn't have made it in. Besides, did this Check Instructor tell you how to visualize your home made FAF?
 
BajtheJino said:
Thats the worst advice I've ever heard. There is absolutely nothing wrong with descending the first moment you can. Theres no towers or obstructions as long as you remain on the approach. Remember, someone has already checked this out to be sure! There have been many times I've shot a VOR approach to a certain airport that if I hadn't got down as soon as I could I wouldn't have made it in. Besides, did this Check Instructor tell you how to visualize your home made FAF?
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Well I can see where he's coming from. Even though it's safe from obstructions, altitude never hurts. As for as my made up FAF, I know that normally FAF's are around 2 miles away, and to descend for abc approach should take about 1 mile, so three miles out I descend.
 
I'm gonna have to agree with Baj on this one. Why would you purposely stay in the clouds when the procedure was designed to get you down as soon as you are established inbound?

Point being...get down
 
Adler said:
Do you know that for sure, or are you just speculating. At KBTL we have a VOR 23 (with a vor on the field) http://204.108.4.16/d-tpp/0901/00041VTG23.PDF that has a FAF; but for the VOR 31, there is no FAF http://204.108.4.16/d-tpp/0901/00041VTG31.PDF
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An approach based on an on-airport navaid *often* does not have a FAF. It certainly can, if there is some means of detecting it. On these approaches, final approach begins where the PT intercepts the final approach course. This point isn't actually an FAF, since it's not an actual fix.

And no, this isn't speculation. ;)
 
Page 5-54 talks about these types of approaches.

Here are my observations:
--The BTL VOR or TACAN or GPS 23 has to cross because the FAF can be identified. The VOR has the R-319 off LFD, the TACAN has DME, and the GPS...well...is GPS. A FAF is identifiable.
--The BTL VOR or TACAN or GPS 31 does NOT have the FAF symbol because of the VOR portion. Notice that with DDALE, you have the same mins as with the approach to 23. TACAN and GPS will give you DDALE. Unless you have an ADF (the 012 reference), a VOR-only equipped aircraft cannot make the step-down. On the 23 approach, there is an 88 deg difference between the FAC and the R-319 cross radial. The FAC and cross radial from LFD would be too close to provide a reliable fix. I think the ol' geometery lesson from high school (long ago) works out that the R-300 from LFD would be the cross radial for DDALE. That doesn't work with a FAC of 300. I'm not saying the math is right, but regardless, that angle would be very small.
 
Adler said:
Well I can see where he's coming from. Even though it's safe from obstructions, altitude never hurts. As for as my made up FAF, I know that normally FAF's are around 2 miles away, and to descend for abc approach should take about 1 mile, so three miles out I descend.
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I would have to disagree with this one. Holding extra altitude can mean the difference between getting below the clouds or staying in the soup.
 
BajtheJino said:
Thats the worst advice I've ever heard. There is absolutely nothing wrong with descending the first moment you can. Theres no towers or obstructions as long as you remain on the approach. Remember, someone has already checked this out to be sure! There have been many times I've shot a VOR approach to a certain airport that if I hadn't got down as soon as I could I wouldn't have made it in. Besides, did this Check Instructor tell you how to visualize your home made FAF?
Click to expand...

I encourage descending ASAP because there is always the chance of breaking out of the clouds. It only makes the job easier.
 
OK, you guys are right on the altitude...this was coming from training when everything is in foggle world, and not IMC. I know have a new view on the subject :)
 
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