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Michael Moe

The Rang of Precision APP.

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Lot of you guys fly the RNP Landing procedures especially in the US. I dont thing we have that much of it here in Europe.

 

But what is the preferred system ?

 

I now that LNAV and sometimes VNAV is used for these RNP´s. (Fcom) down to DA

 

Is there any new more precise system underway?

 

I actually want to handfly the NGX more so might want to try these RNP´s

 

Thanks

Michael

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Hello,

 

Europe is in process of estabilishing RNP approaches where it makes sense (usually that means - where there is no ILS, or single-sided only; plus some airports where it makes sense otherwise.). The process was started years ago, from the initiative of the airlines. Actually, it was an airline that was very dear to me personally, SkyEurope Airlines. See http://www.flightglobal.com/news/articles/skyeurope-bids-to-be-europes-first-requied-navigation-performance-precision-approach-218749/ .

 

The typical example of procedure that started in life as a proprietary bit of kit, and ended up being public, is the Innsbruck RNAV RNP 26 approach. For an example of an RNAV procedure that complements an existing set at an airport with a single-sided ILS, take a look at RNAV (GNSS) approaches at LKTB Brno.

 

Now - as to "preffered" method - that depends on what the airline is certifed for and what the crew are trained for. Personally, I prefer IAN. Those, who do not have it, use LNAV/VNAV, but that is really not too important from the regulations point of view. If the airline proved beyond any doubt that their pilots are trained to, and capable of, maintaining RNP limits with using nothing but HDG and VS modes... then it may use these. (Though I have hard time believing anybody would be able to do that....)

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Thanks for the explanation . This IAN (Indicated Approach Naviation) which i believe is not simulated in the NGX look very simular on the PFD to ILS but is there IAN charts as well or what data does this this come frome and secondly executed?

 

 

 

Thanks

Michael

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IAN is modeled on NGX. You can probably fly any constant angle, non offset, non precision approach. There is no special chart for it.

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This IAN (Indicated Approach Naviation) which i believe is not simulated in the NGX look very simular on the PFD to ILS but is there IAN charts as well or what data does this this come frome and secondly executed?

 

Oh the things people wouldn't miss out on if they read the manuals...

 

Integrated Approach Navigation (IAN) is an option designed to use ILS-like pilot procedures, display features, and autopilot control laws for nonprecision approaches.  Nonprecision approaches are any approaches without lateral and vertical cues, so these would be LOC, VOR, NDB, and other approaches.

 

What IAN does is create a vertical profile.  In the past, on a LOC approach, you would hit a crossing altitude and then descend to the next crossing altitude.  Unless you wanted to do all of the math (or look it up in the tables, and potentially still have to do math), this meant that you would level off until crossing the fix and descending to the next altitude.  With IAN, it calculates a path that hits all of these fixes at the proper altitude in a constant descent, and provides the information to the autopilot on the APP channel (normally this channel only pays attention to the NAV radio signal).  This allows you to use the same procedures to fly a nonprecision approach and an ILS approach.

 

There are no charts for it, as what it intends to do it take existing (charted) nonprecision approaches, and make them fly like precision approaches.

 

Here's Boeing's explanation of it:

http://www.boeing.com/commercial/aeromagazine/aero_22/737approach_story.html#3

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There is no such thing as IAN chart or IAN approach. IAN is a method of flying non-ILS approaches. A display thing, really.

 

Further than that, Kyle, as always, has presented the answers.

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So no reason to bring IAN diskussion in a precision approach thread i guess. But would still love to see a video with this. Thanks it explains it better than the fcom.

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So no reason to bring IAN diskussion in a precision approach thread i guess. But would still love to see a video with this. Thanks it explains it better than the fcom.

 

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it calculates a path that hits all of these fixes at the proper altitude in a constant descent

 

This is called geometric descend path in VNAV mode. I've tested IAN on NGX a lot and can tell that it works differently.

 

For calculating G/P it takes E/D (RW waypoint elevation +50') and the previous waypoint which have altitude restriction. It calculates the angle, which you can see on LEGS page. And it uses only this angle. If there are other approach altitude constraints, it disregards them. 

 

Even on navigation performance scales you can even see the difference between VNAV pointer and IAN calculated G/P. If IAN worked like you've said in quotation, it should show the same as VNAV geometric path.

 

Of course IAN logic could be more complicated than this, however it's definitely not just constant descend, but constant angle. This doesn't mean it will fly all approach fixes on proper altitude.

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Hi to all,

Regarding IAN approach, it's really a big help with that fictive glide path!

This Evening (just few minutes ago) I've executed an approach and landing to Skiathos (LGSK) Greece Island: dangerous and very demanding approach ...rwy lenght= 1623 meters (5324 feet) long and only 30 meters (100 ft) width, NDB approach with offset course (5 degrees) and tonight 8 kts of crosswind....just an error: being worried about overshoot I touched hard with almost no flare...100 meters before the "boxes"...sorry to my pax....

Anyway try the difference on execute this approach by using IAN nav or traditional ndb....(i.e. HDG and V/S) technique....

 

BTW also the takeoff with almost full pax (B738 i.e. 57,5 tons ZFW) and 7,8 tons of fuel on takeoff (Air Italy perform a direct flight LGSK-LIMC) with flaps 25, bleed off, and "takeoff bump 27 k" is very amusing...

Ciao

Andrea Buono

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Hi to all,

Regarding IAN approach, it's really a big help with that fictive glide path!

This Evening (just few minutes ago) I've executed an approach and landing to Skiathos (LGSK) Greece Island: dangerous and very demanding approach ...rwy lenght= 1623 meters (5324 feet) long and only 30 meters (100 ft) width, NDB approach with offset course (5 degrees) and tonight 8 kts of crosswind....just an error: being worried about overshoot I touched hard with almost no flare...100 meters before the "boxes"...sorry to my pax....

Anyway try the difference on execute this approach by using IAN nav or traditional ndb....(i.e. HDG and V/S) technique....

 

BTW also the takeoff with almost full pax (B738 i.e. 57,5 tons ZFW) and 7,8 tons of fuel on takeoff (Air Italy perform a direct flight LGSK-LIMC) with flaps 25, bleed off, and "takeoff bump 27 k" is very amusing...

Ciao

Andrea Buono

 

 

Will definitive try that to , I only have done these none precisions by V/S or by hand so far . I wonder why the approach is offset in Skiathos  It looks like there is plenty of space to the left side(noise abatement ?? city?) so why not just place the ndb/vor´s straight in?)

 

Michael Moe

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For calculating G/P it takes E/D (RW waypoint elevation +50') and the previous waypoint which have altitude restriction. It calculates the angle, which you can see on LEGS page. And it uses only this angle. If there are other approach altitude constraints, it disregards them. 

 

Right - sorry.  As the OP didn't have an understanding of what it was at all, I tried to keep it high level, and managed to mess up my explanation in the process.

 

As it's coded currently, though, it is still proper.  The concept of only using the FAF (which is normally the last restriction), to TDZE + 50' (or TCH 50') is just like you'd see with most non-precision approaches.  All restrictions listed prior to the FAF are the responsibility of the PIC/PF to meet, as they always have been.  Even if there are additional restrictions after the FAF, they are below or coincident with the glidepath (they are normally only used when using a stepped approach, not a computed GP).  As such, computing from FAF/last restriction is appropriate.

 

Example:

KMRB RNAV (GPS) RWY 8

-FAF is 3000' (with a note that it is set at an angle of 3.06 degrees to the TCH of 50')

-Additional restriction is 2000', 3nm away

A little math will tell you that following the 3.06 degree glidepath will ensure you meet the 2000' restriction, as a direct path between the two fixes would be set at 3.14 degrees, which is steeper than the direct GP between the FAF and TCH.

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Hi RSVIT,

 

How do you get the charts and checklists to display the way you have them?

 

Thanks

 

Rob

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