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Michael Moe

Some Questions regarding Charts and procedures

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Hi,

 

Lately i have come by some new procedures that i am not so familar with. Can anyone light up these for me ?

 

Thanks in advance

 

1. RNAV (GPS) and RNAV (RNP) The last one i have tried a couple of times in the T7 and in the NGX (Precision Approach)

2. GLS (For instance GLS RWY09 in KIAH) what is this ?

3. VGSI and RNAV GP not coincident on Approach charts

 

:-) :huh:

 

Thanks

 

Michael

 

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1. RNAV (GPS) and RNAV (RNP) The last one i have tried a couple of times in the T7 and in the NGX (Precision Approach)

 

RNAV GPS uses GPS as a form of RNAV (aRea NAV - basically, the ability to go from any location, directly to another)

RNAV RNP uses multiple forms of RNAV )any combination of: GPS, DME/DME, IRU/INS/IRS)

 

Since you didn't quite phrase it as a question, I'm not sure what you want to know here...

 

 

 


2. GLS (For instance GLS RWY09 in KIAH) what is this ?

 

Google is your friend, but, GLS means GPS-based ILS.  In other words, a GPS approach (using ground-based augmentation, like WAAS), that has positive vertical and horizontal deviation (and a narrowing approach corridor, like a LOC and GS do), offering an ILS-like set of minimums.

 

http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/faq/laas/?print=go

 

 

 


3. VGSI and RNAV GP not coincident on Approach charts

 

Again, Google would've answered this rather quickly, but to save you having to search for it yourself:

 

VGSI - Visual Glide Slope Indicator

RNAV GP - RNAV Glide Path

"Not coincident" - not overlapping

 

...in other words, the PAPI/VASI/etc will indicate you're higher or lower than you should be when you follow the RNAV GP, so you will have to make a small path correction when you transition from instruments to visual references.

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Don't be embarrassed to ask basic questions. A good place to start is the AIM Airman Information Manual free from the FAA here: http://www.faa.gov/air_traffic/publications/http://www.faa.gov/air_traffic/publications/ and also from the FAA is the Instrument Flying Handbook at http://www.faa.gov/regulations_policies/handbooks_manuals/aviation/ all of which are free. Wikipedia is a pretty good source to for a lot of topics. I refer you to the FAA pilot manuals because they have been around a long time and are comprehensive.

 

Basics: You have visual and instrument approaches, each with their own set of rules. Instrument approaches are either precision or non-precision and by current definitions only the ILS is a precision approach because it provides a radio beam for verticle navigation. The GLS is a new type of GPS-based approach that provides minimums equivalent to Cat 1 ILS but is still a non-precision approach. RNP is also a type of GPS-based approach that is more stringent than the RNAV GPS-based approach because of crew training and equipment requirements.  When off-airway navigation first got started, it was done with on board computers that used existing VOR stations to created pseudo locations and the term RNAV was coined. Today, all RNAV is based on GPS and I guess that is part of the answer to #3 but I'd have to guess. I'll stop here before too much of my ignorance shows.

 

Hit the books, a ground school of several weeks is normally required before solo flight.

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Thanks for the answers.

 

I dont think i have any aircraft in my hangar for the GLS not that i need it. Still strange to me as a new none precision.

 

Edit. Great links with answers including which aircraft and the sls4000 precision system.

 

Now where do i find a GLS video? hmm YouTube maybe.....

 

 

Michael

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I dont think i have any aircraft in my hangar for the GLS not that i need it.

 

NGX uses IAN, which is good enough for GLS, I think...provided it's a GLS approach in the sim (the sim doesn't have WAAS, but the sim's GPS is "perfect" anyway, so WAAS isn't necessary i the sim).

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Thanks. I guess Navigraph also plays a role if they supports GLS. Will have a look at KIAH with the latest 07 build.

 

Michael

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Sorry to hijack the thread momentarily but I´ve had this question for a number of years now. I´ve been using IAN a lot when given Rnav approaches whilst flying online in Europe and USA. IAN is simply a great idea in my opinion, by making the transition from ILS to Rnav approaches that much easier and intuitive. At least to me, by simulating the ILS needles IAN keeps things simple and comfortable. I´d imagine most rw drivers out there so used to flying the ILS needles would feel the same way.

 

But how common is it, really? When given RNAV approaches do pilots use IAN in 737s that have this option installed? Do they need special training and/or authorization to use this "approach mode?"

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Sorry to hijack the thread momentarily but I´ve had this question for a number of years now. I´ve been using IAN a lot when given Rnav approaches whilst flying online in Europe and USA. IAN is simply a great idea in my opinion, by making the transition from ILS to Rnav approaches that much easier and intuitive. At least to me, by simulating the ILS needles IAN keeps things simple and comfortable. I´d imagine most rw drivers out there so used to flying the ILS needles would feel the same way.

 

But how common is it, really? When given RNAV approaches do pilots use IAN in 737s that have this option installed? Do they need special training and/or authorization to use this "approach mode?"

 

Put RNP (LNAV/VNAV) in these common questions as well.

 

Maybe USA is using it more than europe ?

 

Michael

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But how common is it, really? When given RNAV approaches do pilots use IAN in 737s that have this option installed? Do they need special training and/or authorization to use this "approach mode?"

 

[FAA-land]

Not very common, currently.  It's part of the reason for the BEBS concept I was working on at my last job.  Basically, there aren't enough aircraft in the fleet mix to justify moving from ILS to RNAV-based approaches, so they just don't issue them that often.

[/FAA-land]

 

...as for the rest of the questions, I have no idea.

 

 

 


Put RNP (LNAV/VNAV) in these common questions as well.
 
Maybe USA is using it more than europe ?

 

We might be using it more, or we might be using it less, but we're sure as heck not using it that often.

 

The FAA is actually still looking into an idea called Best Equipped - Best Served, where those with RNAV RNP capability would be allowed to jump ahead of people in the arrival stream to land, essentially.  Using RNAV RNP would greatly help the airspace issues we have in New York, and Chicago.  Additionally, it would help to allow higher throughput at PHL and SFO (utilizing offset RNP approaches alongside ILS approaches).

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Using RNAV RNP would greatly help the airspace issues we have in New York, and Chicago.

 

In the non-131 environment such as corporate aviation, RNAV terminal procedures are the preferred choice as long as they meet minimums. These procedures generally mean a lot less instructions (intrusion) from ATC and less time in queue - except at the primary dozen or so commercial hubs. As for the NY and Chicago messes and with all due respect to my collegue who is closer to ATC than I ever will be (ignoring that I one of my wives was a controller), when I comprare the progress made at Dallas and Houston I can't help but wondering if the problems is the turf battle between competing FAA facilities especially in NY. Look at Dallas for example, KDFW and KDAL as close as JFK and LGA and throw in a busy Navy base with two very busy non-131 airports and yet it works pretty smoothly on most days. Granted, DFW has lots of runway and even little Love is bigger that LGA.

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Hi,

 

I jumped inti this thread instead of opening another topic on the same matter, sorry.

 

I flew to Porto LPPR yesterday and noticed something I don't really understand.

 

There are a DVOR 35 and Locator 35 approach at this airport. Looking at the OCA for the straight-in approach, I noticed that the OCA of the DVOR (600ft) is lower than the one of the Locator (950ft).

 

What is the difference between both. I know that I tend to confuse Locator with Localizer as the frequency is in the same range but I guess there are different? What is the difference between the localizer wich is one part of the ILS and the locator?

 

Could somebody bring me a clear view of the three different kind of aid (DVOR, Locator, LLZ)?

Thanks

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LOC approach uses one of two components of the ILS system, which is the Localizer and it consists of two VHF beams projected from an antenna nearly as wide or wider than the runway located at the far end of your approach. This beam is very accurate. A locator, we have one in the USA at KDCA, is a beam projected from a single antenna that looks more like a NDB than Localizer, and I am not sure of it's accuracy but it is only good enough to get you to the right end of the airfield. The VOR (or DVOR, includes DME) is a completely different beast and its required navigational accuracy is +/- 6 degrees, which is a far cry from the azimuth accuracy obtained from a localizer but it is better than a locator; however, the DME does provide a very accurate distance measurement and the designers of this approach must have found that to be an advantage is computing the approach minimum.

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In the non-131 environment such as corporate aviation, RNAV terminal procedures are the preferred choice as long as they meet minimums. These procedures generally mean a lot less instructions (intrusion) from ATC and less time in queue - except at the primary dozen or so commercial hubs. As for the NY and Chicago messes and with all due respect to my collegue who is closer to ATC than I ever will be (ignoring that I one of my wives was a controller), when I comprare the progress made at Dallas and Houston I can't help but wondering if the problems is the turf battle between competing FAA facilities especially in NY. Look at Dallas for example, KDFW and KDAL as close as JFK and LGA and throw in a busy Navy base with two very busy non-131 airports and yet it works pretty smoothly on most days. Granted, DFW has lots of runway and even little Love is bigger that LGA.

 

I definitely agree with corporate preferring the RNAV stuff, but corporate traffic doesn't usually cause too much of an issue because they're usually using reliever airports, and fleet mix isn't usually an issue there (with the exception of TEB, perhaps).  Controllers and pilots alike usually have a lot less work to do to clear/fly the approach, so there's a distinct advantage.  The issue is that you really don't want to run multiple procedures to the same runways, and most all of the aircraft out there are at least ILS-equipped (into the fields where you have enough constant traffic for it to matter).  As such, the ILS is what gets assigned the vast majority of the time (into those fields).

 

Not sure what your friend does, but I was referencing work that I, personally, did with the FAA HQ and ATCSCC to address the issues, with N90, ZNY, and C90 representation in there (along with other facility TMU people simply as SMEs).  I don't recall DAL/DFW ever coming up, but looking at their facilities, it kinda makes sense.  If the ceiling drops, DFW can shift to their 13s to allow DAL to run the ILS to their 13s.  That's not an advantage N90 has.  If JFK goes 13s, then LGA is forced into 13 ops, which then puts EWR and TEB in a spot (because EWR can't reasonably use 11 for the fleet mix to the field, EWR has to share airspace with TEB to get aircraft in and out).  As far as military facilities go, those departures are managed as they come up, and down there, they all have runways in the same general direction without too much overlap.

 

 

 

 

 

 

EDIT:

Earlier, I wrote GPS-based ILS approach.  It's GBASS Landing System.  I'm really hoping I was distracted when I wrote that, because GPS-based ILS approach is probably one of the worst ways to describe it. (Thanks to Ryan for noticing that.)

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Hi Dan,

 

Thanks for that quick and clear answer! It clears up my misconception about the locator which I stupidly found closer to the localizer than the VOR because of its frequency range.

 

Now I understand the reason for the minima.

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For testing my primitive skills (still only a hobby pilot here :-) ) i desided to go for a RNAV17L in KDEN Denver.

 

First with Chart RNAV ( RNP) in LNAV/VNAV Path 0.30 DH377 and then a second try with Course related IAN (173) and FAC G/P. Worked like a charme.

 

Only Q remain is the 2 different RNAV Procedures. RNAV GPS and RNAV (RNP) for KDEN 17L. Both Procedures makes use of LNAV/VNAV.

 

I thought the RNAV"GPS"  procedures was for smaller planes without LNAV/VNAV.?

 

That leads to the Q. Is both procedures "acceptable" in the B737+B777 ?

 

 

Thanks

Michael :-)

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i desided to go for a RNAV17L in KDEN Denver.

 

A reasonable choice (and the choice of the future), but again, I'll stress that you shouldn't expect similar if you fly RW or on VATSIM.  ILS reigns supreme...for now.

 

 

 


Only Q remain is the 2 different RNAV Procedures. RNAV GPS and RNAV (RNP) for KDEN 17L. Both Procedures makes use of LNAV/VNAV.
 
I thought the RNAV"GPS"  procedures was for smaller planes without LNAV/VNAV.?

 

RNAV(GPS) and RNAV(RNP) isn't a matter of "do they use LNAV/VNAV?"  It's a matter of "can they maintain the RNP for the approach?"  RNAV(GPS) isn't about aircraft size, or use of LNAV/VNAV.  It's that it isn't an RNP approach, and that it specifically uses GPS as a method of RNAV.

 

For what it's worth, some of United's 757s can't do most of the RNAV approaches out there because they don't have GPS (at all - they're DME/DME/IRU - but since the chart says "RNAV(GPS)" it requires GPS).  Meanwhile, corporate jets (as Dan mentioned earlier) have been doing this for quite some time.  Don't fall into the aircraft size trap that everyone seemingly falls into.

 

Remember:

RNAV is "aRea NAV."  It's simply a concept where a plane can go from one point in space, directly to another (doesn't rely on VOR radials and so on).  GPS is a method of RNAV.  Inertial Reference is also a type of RNAV.  GPS and INS are concepts of the larger concept called RNAV, just like turbojets and props are concepts of the larger concept called airplanes.

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A reasonable choice (and the choice of the future), but again, I'll stress that you shouldn't expect similar if you fly RW or on VATSIM.  ILS reigns supreme...for now.

 

 

 

 

RNAV(GPS) and RNAV(RNP) isn't a matter of "do they use LNAV/VNAV?"  It's a matter of "can they maintain the RNP for the approach?"  RNAV(GPS) isn't about aircraft size, or use of LNAV/VNAV.  It's that it isn't an RNP approach, and that it specifically uses GPS as a method of RNAV.

 

For what it's worth, some of United's 757s can't do most of the RNAV approaches out there because they don't have GPS (at all - they're DME/DME/IRU - but since the chart says "RNAV(GPS)" it requires GPS).  Meanwhile, corporate jets (as Dan mentioned earlier) have been doing this for quite some time.  Don't fall into the aircraft size trap that everyone seemingly falls into.

 

Remember:

RNAV is "aRea NAV."  It's simply a concept where a plane can go from one point in space, directly to another (doesn't rely on VOR radials and so on).  GPS is a method of RNAV.  Inertial Reference is also a type of RNAV.  GPS and INS are concepts of the larger concept called RNAV, just like turbojets and props are concepts of the larger concept called airplanes.

 

 

Thanks alot Kyle :-)

 

Again from Denmark and using Navigraph Charts they do have RNP and LNAV/VNAV DH(A) on there RNAV(GPS) Charts.

 

That why i get confused i think :-)

 

Michael

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Michael, I'm not familiar with Denmark charts but I am guessing that you are referring to different minima for LNAV/VNAV and LNAV only? My panel has a Garmin 530 that provides for LNAV only RNAP(GPS) approaches but high-end (i.e., pricey) systems will provide vertical (VNAV) clearance as well, which logically allows the procedure designers to assign a lower DH or minima. RNP is actually a very different philosophy from RNAV(GPS) in that in RNP there are requirements for crew training and the equipment must provide additional information to the pilot regarding actual navigation performance and deviations and the equipment generally includes VOR/DME/IRS and GPS input; but RNAV(GPS) is just GPS and without WAAS can have an acceptable errors in excess of 100 m (I forget the actual CEP but it's greater than that).

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high-end (i.e., pricey) systems will provide vertical (VNAV) clearance as well, which logically allows the procedure designers to assign a lower DH or minima.

 

...but they're nice, aren't they?  There was some CPA around here who had a Malibu that I got to toy with occasionally.  He always had the latest and greatest.

 

I used to be very skeptical of getting rid of ground-based navaids in favor of GPS, but after WAAS and other GBASS implementations, I'm pretty much sold.  Add RNP into that, and I'm ready to convert...at least theoretically. ha ha.

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Regarding GPS with SBAS and GBAS, we use them extensively in my job on offshore construction vessels for precised positioning (I'm merchant seaman), calling them generically DGPS (Differential GPS) and despite the fact they can provide positions as precised as 10cm, they are quite sensitive to atmospheric perturbations (especially scintillation due to sunspot).

It leads to erratic positions and even complete loss of signal in some areas of the globe and some periods of the day.

 

I guess the systems used in airplane are also sensitive to the same perturbations? Or are there magic bullets?

Otherwise, I'm not ready to give 100% trust to these systems yet, not without ground-based backup aids.

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Michael, I'm not familiar with Denmark charts but I am guessing that you are referring to different minima for LNAV/VNAV and LNAV only? My panel has a Garmin 530 that provides for LNAV only RNAP(GPS) approaches but high-end (i.e., pricey) systems will provide vertical (VNAV) clearance as well, which logically allows the procedure designers to assign a lower DH or minima. RNP is actually a very different philosophy from RNAV(GPS).

 

 

 

 

 

 

Hi,

 

Yep i am refering to Minima LNAV/VNAV on the GPS Charts in which RNP also is mention.

 

Thanks

 

Michael

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I'll add a little more fun to this.  Even though there are VNAV minima on the charts, not too many operators have the authorization to use VNAV anyway.  We have to use LNAV only as that is all our Operations Specifications allow at this time. Most VNAV minima will bring you down 250 feet AGL.  ILS (Radio Based) will bring you down most often to 200 feet agl.  So it's very true, the ILS is assigned most often in lower weather.  Most of the time you will get the approach lights and when you do, most Ops Specs will allow you to then decend down to 100 feet ABOVE the touchdown point, allowing us to then get in when weather is REALLY crummy.  200 ' and 1\2 mile vis.  Most airlines (FAR PART 121 operators) have the same abilities, so for FSX purposes it might add some realisim to remember the decend to 100 feet above the Touch Down Point rule when you get the approach lights.  Makes for some really great flights.

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Thanks,

 

All though all this is basic stuff for all of you i am glad you take your time to answer these questions as i do find it a little hard to just Google all this  :rolleyes: and lead it to real life meaning full information

 

Thanks again 

 

Michael

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I guess the systems used in airplane are also sensitive to the same perturbations? Or are there magic bullets?
Otherwise, I'm not ready to give 100% trust to these systems yet, not without ground-based backup aids.

 

In a nutshell, yes. The most basic of TSO's GPS devices have multiple channels and pertubation sensing as well as NOTAMs issued to warn of solar activity forecasts. I would not want to go back to VOR/LORAN only navigation, and I am really spoiled by adding a XM receiver to download current METARs and NEXRAD from NWS that appears right on the map display. We also use GPS systems for surveying at the engineering company I recently retired from, which is a real money saver because all the data is electronically stored and when brought in from the field and put in an engineering workstation the productivity and quality is significantly increased. Now days, this is a tool that you either use or you lose the business to someone else that has it.

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For sure, we can't get rid off GPS systems. Only they need in some case to be backed up, in our case with other position references as HPR (hydroacoustic) or laser beam system. 

DPGS with different types of corrections may react differently to the perturbations but in particularly sensitive areas like in Gulf of Guinea, I have seen all the vessels losing all the GPS signals at the same time whatever equipment they have.

 

 

In the case of landing system, the only system to my knowledge which allows autoland is ILS for the moment.

I don't when the GPS will be reliable and precised enough to completely replace ILS?

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