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Jimm

Understanding Approach Charts

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This year, I went ahead and bought a subscription to Navigraph Charts.  I find it to be a very useful product when planning flights.  I have come across something I am unfamiliar with, and perhaps has gotten me in some sticky situations, more specifically with approaches.  When determining a given arrival, I typically get a runway from PFPX, to which in turn, I complete my flightplan via the MCDU, where it asks for a runway and then a STAR.  When conferring with the charts, I see that some airports have many different approaches for the same runway.  For example, at LGAV, runway 03R, I have an option for ILS X/Z 03R ILS Y 03R, but I cannot tell the difference.  Other airports seem to be cut and dry for approaches to their runways, but for the example above, I don't know which ILS to choose from.  I am still able to complete the route and fly to the STAR, but every once in a while, on approach, I cannot get the APPR to engage, and I have to override the aircraft and fly in manually.

 

I am still learning quite a bit now, but for these approaches, I am wondering if I am still missing something that I should understand or something I should already know to pick out the correct approach from the charts.

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I am still learning quite a bit now, but for these approaches, I am wondering if I am still missing something

 

4 parts series

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Often these approaches will have different minima for obstacle clearance on the missed approach.  See if the chart has a minimum climb rate requirement on it and check the minima.

 

Also there's a Flight School forum where you might find some answers here and there...which needs a great deal more participation.

 

http://www.avsim.com/forum/498-the-flight-school-hangar/

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Good question, as I'm in a similar position. Have watched a few video tutorials on youtube and that has helped - the Baltic Aviation Academy one is pretty clear and straightforward.

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I did watch the video(s) that Pete recommended and they did shed some light on things, but most I already knew.  I looked at the STAR charts for LGAV for RWY03R, which have a X,Y, & Z option.  I did find that X and Z are for CAT I & CAT II landings, so that is what differs for those.  I think a more broad answer to my own question would be that looking at the charts in greater detail will help differentiate.  I just need to provide myself more time planning my STARs and not rushing them before takeoff.  As I said before, many STAR approaches are cut and dry, but it's these approaches with X,Y and Z options that got me, but I think I'm a little wiser now.

 

Thanks guys.

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Lettered variations to an approach simply indicate that there are differences between the various versions.  Often these differences are subtle and as Gregg notes one of the most common is a difference in the approach minimums.  You have to be extra careful with these as lower approach minimums are typically coupled with some very aggressive climb gradients on the missed approach.  If your aircraft can't meet these climb requirements you'll want to fly the approach with the higher minimums.

 

Scott

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Lettered variations to an approach simply indicate that there are differences between the various versions. Often these differences are subtle and as Gregg notes one of the most common is a difference in the approach minimums. You have to be extra careful with these as lower approach minimums are typically coupled with some very aggressive climb gradients on the missed approach. If your aircraft can't meet these climb requirements you'll want to fly the approach with the higher minimums.

Scott

 

Yeah, I looked for the original question where you answered the same thing for me a long time ago but couldn't hunt it down.  So, credit where it's due...this guy knows his sh...stuff. :smile:

 

Gregg

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...this guy knows his sh...stuff. :smile:

 

As long as it's been since I've flow as PIC IRL, I think I've forgotten more than I ever knew! :-)

 

Scott

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Surprised someone currently instrument rated has not chimed in here.  The differences are based on pilot certification, equipment, and avionics performance. So the pilot must know the parameters and limitations of his equipment and pick the appropriate approach.  For ILS approaches the aircraft's Vref  speed and the level of pilot certification are the determining parameters and the Vref is relevant to obstacle clearance.  The same is generally true for RNAV (GPS) approaches, but I was way too early for instrument certification for those so I will point to the best reference I could quickly find.  Scroll to page 4-8 and use that as your starting point. The link points to a large pdf file so it may take some time to load.  It may well be worth the wait for you.

 

http://www.faa.gov/regulations_policies/handbooks_manuals/aviation/instrument_procedures_handbook/media/chapter_4.pdf

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Now I feel like I've opened a huge can of worms.  I appreciate everyone's input and I'll get back to you all in about a month while I study. lol

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Now I feel like I've opened a huge can of worms.  I appreciate everyone's input and I'll get back to you all in about a month while I study. lol

Can of worms? No! but your question is a good one for many here to ask and you have opened a door for yourself to new knowledge and sense of accomplishment!

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Surprised someone currently instrument rated has not chimed in here. The differences are based on pilot certification, equipment, and avionics performance.

 

Yes, and no.  An RNP approach seems to be one of the things you're referencing here, where pilot certifications and equipment certainly apply.  But an X,Y or Z approach (be it ILS, RNP or whatever) simply means that while these approaches are of the same type, something is different.  It may be different minimums and associated differences in perfomance requirments for the same class, it may be different equipment requirements, it may mean different approach fixes.  But strictly speaking it doesn't necessarily indicate different pilot certification, avionics performance or equipment.

 

It just means there's a difference of some sort even though the base approach type is the same.

 

See for example the KJAC ILS 19 Y and Z approaches.  In this case, the approach fixes are different, with one using GPS fixes and (obviously) requiring an IFR certified GPS), the other simply requiring ILS/VOR capabilities.  This is one of many examples of the kind of differences inherent.  Some may require different performance, some different equipment, some none of the above - simply an alternative with different parameters.

 

http://155.178.201.160/d-tpp/1605/00504IZLD19.PDF

 

http://155.178.201.160/d-tpp/1605/00504IYL19.PDF

 

In the case of an ILS X,Y or Z approach, for example, there would never be a difference in pilot qualifications - only differences in procedure (fixes), avionics and/or performance.

 

Scott

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Regardless, one should never choose an approach and runway based on departure. The weather can change and winds can alter the active making changing the approach in flight a pain. Especially with one pilot flying a two man aircraft, it can be a hassle trying to fix an approach last minute. It's better to be ready to enter it as soon as you are cleared (or you've heard ATIS). Of course there are times in the real world when they'll give a change 15 miles out but that's another story. It's a little more difficult in sim simply because ATC is so poor (unless online with good controller) and operating the plane can be tasking.

 

Last night for example I flew into KEWR. ATIS reported RWY 4L and R as active. I thought great, my assumption based on minimum winds was wrong so I'm probably gonna be high. Well after hurrying down for the IAF to 4L I hear ATIS say runway 22s are now active. Not a happy camper. I never fly into KEWR and was not prepared to go around and land opposite downwind. It was the MD11 and I rarely fly it anymore so I was even less prepared. Either way, it happens in the real world too.

 

To assume that you'll be cleared to a specific STAR and IAP is poor practice. In the real world those plans are altered frequently for traffic and other routing. If you are on a STAR to filter for a specific set of runways and those runways change direction, then you'll be vectored or cleared to a new fix entirely.

 

Be more concerned about airspace, MOAs and TRFs than anything. That's my opinion.

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To assume that you'll be cleared to a specific STAR and IAP is poor practice. In the real world those plans are altered frequently for traffic and other routing. If you are on a STAR to filter for a specific set of runways and those runways change direction, then you'll be vectored or cleared to a new fix entirely.

 

I think most FMS's require you input a complete route, with SID and STAR before departure? I agree it's bad practice but you kinda have to assume at departure and then update it later if things change.

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In the real world, we would have a good idea of what to expect for arrival beforehand. Atis for the destination can be pulled up via acars at anytime so that the expected runway and arrival transition can be programmed already. And many stars will have different transitions based on the runway in use, so even if you don't have the atis, the controller working you at the time of beginning the arrival will inform you of which transition you're doing. With the ability to pull up whatever information we need via acars, we would have the arrival briefing completed about 40 minutes prior to arrival. If things change, and they do, we just reprogram and rebrief. Obviously, you don't have all this info in msfs, but you can always check the real world weather ahead if you use real weather and you do have some influence on what runways will be active if made some afcad adjustments. So it does't have to be a complete surprise in msfs.

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I think most FMS's require you input a complete route, with SID and STAR before departure? I agree it's bad practice but you kinda have to assume at departure and then update it later if things change.

No not really. You enter a flight plan that includes a STAR often and if needed ATC will change it. But the FMC does not require anything, let alone a full flight plan. You can enter a departure and arrival airport and nothing else if desired. Same with the waypoints. You don't need to touch the STAR page if you don't want to. A lot of real world flight plans are devoid of a STAR. They simply give a route with waypoints terminating near the airport despite a STAR(s) being available.

In the real world, we would have a good idea of what to expect for arrival beforehand. Atis for the destination can be pulled up via acars at anytime so that the expected runway and arrival transition can be programmed already. And many stars will have different transitions based on the runway in use, so even if you don't have the atis, the controller working you at the time of beginning the arrival will inform you of which transition you're doing. With the ability to pull up whatever information we need via acars, we would have the arrival briefing completed about 40 minutes prior to arrival. If things change, and they do, we just reprogram and rebrief. Obviously, you don't have all this info in msfs, but you can always check the real world weather ahead if you use real weather and you do have some influence on what runways will be active if made some afcad adjustments. So it does't have to be a complete surprise in msfs.

That's correct; however, as stated you don't have this luxury in sim and nothing in the sim or real world stipulates that one must enter a STAR or arrival. If it's part of your plan then great but changes can occur anytime. So it's still poor practice to assume beforehand just to be stuck at the last minute.

 

In the sim I think it's best to use what is active in the real world and go with that. I use flightaware and use those plans. Then tune ATIS and listen for the active. Usually it won't change but I force winds just to be safe. Too annoying to rely on ridiculous changes last minute without warning. As you said, real wold is so much different but it's not perfect either. So I fly the active STAR based on flightaware and figure out my IAP based on the runway in use. Works best I think.

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To assume that you'll be cleared to a specific STAR and IAP is poor practice

 

This depends on the company SOP I would say.

 

Some companies require all flight plans to be "closed" up to destination airport before departure. If there's a change later on, pilots will update accordingly.

 

I personally prefer leaving the route open, that is, NOT selecting a STAR/APP until "within range" of destination airport.

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This depends on the company SOP I would say.

 

Some companies require all flight plans to be "closed" up to destination airport before departure. If there's a change later on, pilots will update accordingly.

 

I personally prefer leaving the route open, that is, NOT selecting a STAR/APP until "within range" of destination airport.

I'd imagine it has more to do than just SOP per company. Either way, most flight plans are complete when filed and changed accordingly as needed. STARs are essentially a way to filter traffic into a sector and usually required for larger busier airports. They will navigate you through MOAs and other airspace as needed and provide a highway of sorts to the airfield. Typically you can see which STAR will be required based on your direction of travel. Of course some aiports have several that all come from one direction and that changes for whatever reason. One can look at NOTAMs at anyone time and see that a lot of STARs are not to be used.

 

Basically my assertion is that there's nothing wrong with selecting a STAR that works best for your route, rather not to select an arrival before you know what runways are in use.

 

ETA: we're off topic at this point. The OP was asking mainly about arrivals and X,Y, Z designators. That is where I disagree. Selecting an actual arrival prior to know what runway is active. If it's changed halfway through or 25 miles out, it's gonna be annoying trying to fix it in the FMC. Mainly when IFR. The lack of ATC for proper routing makes simulation more of hassle in that regard. I realize at the end of the day navigation and flying is the pilots job but ATC is there for traffic routing. The majority of the time pilots will do as ATC instructs. Only when the instruction is unsafe or unrealistic will pilots buck the system. Pilots have been reprimanded for not following ATC instructions.

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Basically my assertion is that there's nothing wrong with selecting a STAR that works best for your route, rather not to select an arrival before you know what runways are in use.

 

Agreed!

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I think most FMS's require you input a complete route, with SID and STAR before departure? I agree it's bad practice but you kinda have to assume at departure and then update it later if things change.

I've only been flying airliners properly for a couple of months now, so for right now, I am just getting used to the process of getting the MCDU programmed and following through with a complete flight.  I have yet to delve into the advanced aspects of approaches as I typically (for now) allow the aircraft to autoland.  My original post was intended to be a simple question as to why approach charts have the X,Y and Z designation, but I am seeing why now.  I DO appreciate the feedback and all of the external resources available, so when I get the time, I'll sit down and read through it all.

 

Right now, I do have a pretty good handle on the basics of programming the MCDU, and for the most part, my flight plan are pretty cut and dry.  Having Navigraph charts is a very big help, for both the programming and for learning.  I use PFPX initially, to get the route and export it to my aircraft and then when I am in the cockpit, I review the plan BUT I also program in the STAR approach and RWY ahead of time.  As I have known though, it isn't general practice as it has been stated above that RWYs and approaches can change, which I will save those scenarios for another day. :)

This depends on the company SOP I would say.

 

Some companies require all flight plans to be "closed" up to destination airport before departure. If there's a change later on, pilots will update accordingly.

 

I personally prefer leaving the route open, that is, NOT selecting a STAR/APP until "within range" of destination airport.

I hear what you are saying but as a noob question to be asked:  wouldn't waiting until the last minute, say just before TOD, change the TOD and all calculated ALTs and speeds?  I heard not long ago, that with respect to the precious passengers, when you initiate descent, you don't want the aircraft to slow down too much or change the vertical path where it feels like a roller coaster. lol

 

I fly the Airbus and it does a pretty good job at TOD, to hold a shallower rate of descent and speed, to make the transition less rough.  I will typically leave the PERF page up on the MCDU and watch the distance to TOD, and when it hits about 1 mile, I'll initiate descent.  

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wouldn't waiting until the last minute, say just before TOD, change the TOD and all calculated ALTs and speeds?

 

Sure, but you don't wait "to the last minute"

 

When you're within 200nm (or so) from destination, you should start receiving the ATIS. At this point you can prepare and brief for the approach.

 

In practice, what I do in the Sim, is leave the arrival open, take-off and climb to cruice, go have some coffee, and then I come back to the "cockpit" and I study the arrival well, install it into the FMC etc. This way I don't "lose time" on the ground and do the arrival programming while flying and covering miles...

 

I also usually draw a green 200nm ring around destination airport (using FIX page, on Boeing), in case I "forgot" to program the arrival :)

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Sure, but you don't wait "to the last minute"

 

When you're within 200nm (or so) from destination, you should start receiving the ATIS. At this point you can prepare and brief for the approach.

 

In practice, what I do in the Sim, is leave the arrival open, take-off and climb to cruice, go have some coffee, and then I come back to the "cockpit" and I study the arrival well, install it into the FMC etc. This way I don't "lose time" on the ground and do the arrival programming while flying and covering miles...

 

I also usually draw a green 200nm ring around destination airport (using FIX page, on Boeing), in case I "forgot" to program the arrival :)

That is an excellent point, although some of my short haul flights don't have the luxury of a 200nm distance between TOC and TOD. lol

 

I do understand what you are saying though.  You mentioned fixes and while I have seen them drawn in the Boeing FMCs, I have to figure out how to do them in the Airbus.  I know they can come in handy, and this tip you gave is a great one to use, thanks.

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The whole assertion that vertical path on descent must be shallow is false. Typical initial descents are around 2000 to 3000 feet per minute and speed is high. The engines will idle and descent is initiated with the descent path usually holding speed. Sometimes spoilers are needed too. That whole "1000 feet or less for passenger comfort" is silly. ;-)

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That is an excellent point, although some of my short haul flights don't have the luxury of a 200nm distance between TOC and TOD. lol

 

For very short flights, without a "relaxed" cruising phase then yes, you'll have to install the arrival before taking-off as well :)

 

 

That whole "1000 feet or less for passenger comfort" is silly. ;-)

 

Also, passengers don't feel vertical speed.

 

That being said, vertical speed and path are different things. A 3º glide path at 500GS results in 2500fpm. At 140GS it's 800fpm. It's three times less, yet the glide angle is the same! :)

 

What passengers feel is CABIN rate of climb/descend, and deck angle. (Passengers have the annoying and stupid tendency of fearing a deck angle of 30º, but what do they know! hahaha)

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The whole assertion that vertical path on descent must be shallow is false. Typical initial descents are around 2000 to 3000 feet per minute and speed is high. The engines will idle and descent is initiated with the descent path usually holding speed. Sometimes spoilers are needed too. That whole "1000 feet or less for passenger comfort" is silly. ;-)

I never said it was a "must".  After I initiate a descent, I watch the magenta dot, and I watch the altitude and speed.  After initiating the descent, the descent rate does fall at around 2000, but the speed is managed to a point when the aircraft's altitude intersects with the descent path and then the engines spool down to idle.  From there, it's pretty much idle as the aircraft tries to maintain the path.  I have also had instances where drag was required, and I'll deploy spoiler...not as hard as I thought it to be.

 

Actually, this brings me back to my first question again about choosing the correct approach with accompanying STAR.  Last flight I performed from OMDB to LGAV, I had picked an approach out of the 3 three available for RWY03R, but for some reason, my aircraft failed to capture the glideslope, so my quick actions came into play and I wound up landing the aircraft manually.  I think this had something to do with the approach and the mountainous terrain.

 

I don't get too worked up about it though.  It is, after all, a simulator. :)

For very short flights, without a "relaxed" cruising phase then yes, you'll have to install the arrival before taking-off as well :)

 

 

 

Also, passengers don't feel vertical speed.

 

What passengers feel is CABIN rate of climb/descend, and deck angle. (Passengers have the annoying and stupid tendency of fearing a deck angle of 30º, but what do they know! hahaha)

I think it's more courtesy than anything to descend at a rate that doesn't take people by surprise.  I have flown a few redeye flights and I think pilots don't want to scare anyone if their still asleep.

 

As a passenger of various aircraft, I can tell when an aircraft is going a little deep and steep on the vertical angle and I think this is what the person I heard from was talking about. My wife hates flying, and when the descent phase is initiated, she gets that terrified look on her face.

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