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markadeane

Non-precision approaches w/o ILS guidance

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Hi all,I'm looking at writing a wiki article on how to carry out non-precision approaches where a runway has no landing guidance such as an ILS or VOR/DME. Granted these sorts of scenarios aren't too common, but I had a flight recently where I decided to try using non-precision methods such as v/s mode to manage descent down to about 5 miles on final before I took control. I found it to be quite fun!What I'm after are people's personal techniques to manage a non-precision approach without navaid guidance. This can be either with VNAV or without. Real world techniques from our real aircrew forums members would be most appreciated. Rules of thumb, ways to determine the best vertical speed to use, tips on handflying an approach without guidance etc etc etc are all appreciated.Anyone who offers advice will be credited if I do write the article obviously. Cheers!

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There are many different non-precision approaches. In fact, the only precision approach is the ILS (military has Ground Control Approach RADAR (GCA) but they are getting rare). Non-precisions include LOC, LDA, RNAV (GPS & RNP), NDB & VOR... each has it's own quarks. Finally, there is the visual approach which may or may not be flown with any reference to a navaid... is this what you're referring to?Might help if you also specify the type (737 or 747).

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Gents, thanks for the initial feedback, my apologies for not clarifiying but I am referring to the 744. As for the specific non-precision approach types, I'm open to any available techniques for any of the variants. The specific area I am interested in are those without vertical path guidance but any contributions are welcome.Also to clarify another point, I am well aware of the existing technique documentation and diagrams in the manual. (thanks Ben in any case!) What I am after here are the individual user's techniques that supplement the SOPS in the manual. Everyone has their own methods and tricks to manage their aircraft and I want to get an idea of the differences and variations therein.Cheers

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Mark:As the previous message says, there are many types of non-precision approach (NPA). You seem to be suggesting that any approach flown without reference to a NAVIAD is an NPA---that's the source of your confusion. Any such approach is purely visual. An NPA refers to an approach involving guidance other than ILS or ILS/DME; eg, an approach wihout glideslope information such as a VOR approach in which the required rate of descent is either based on distance (as where a colocated DME exists) or timing (from the FAF at a known distance). If you look at the approach plate for any NPA, you'll find that information. You'll also find the MDA (minimum decision altitude) at which a go-around must be initiated unless the runway environment is in sight. For an ILS approach, a [typically lower] decision altitude [DA] will exist---in the US, the older term DH [decision height] is still used. Regards,GWI[EGKA]

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Thanks for the clarification, I'll need to go away and look at a bit more reading before I do this article it seems! This is what happens when I only ever do Precision Approaches I guess, still it's nice to find an area where I can learn a lot more. Thanks for all your help thus far guys.

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>Rules of thumb, ways to determine the best vertical speed to>use, tips on handflying an approach without guidance etc etc>etc are all appreciated.A rough figure used is to multiply your ground speed by 5 to get your rate of descent on a 3.00 degree approach.i.e Ground Speed = 140kts, then rate of descent = 140 x 5 = 700ft/min.Or you can half your Ground Speed and add a zero to the end.i.e Ground Speed = 150kts, then rate of descent = 75+0 = 750ft/minWhatever you find easiest.

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>Mark:>>>in the US, the older term DH [decision height] is>still used. >>Regards,>>GWI>[EGKA]Actually, in the US, MDA is used for non-precision approaches, DA is used for Category I ILS (where the baro altitude is your decision point), and DH is used for CATII and CATIII ILS approaches, where the radar altimeter (measuring height) is your decision point.Best wishes

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Timothy:Point taken about DA/DH---thanks for the clarification. I might just add that when I did my FAA IR in the States 25 yrs ago, this was my instructor's view.George

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