In the interest of more realism in FSX, I'm taking Mark's advice (and a few other's, too), and starting to fly without the FSX ATC. However, I was wondering how you would know when to start your descent in a jetliner that doesn't use VNAV, for instance the 707. Of course, in the 757 or 767, VNAV would start the descent for you, but what if you don't have VNAV? Do you just decide? And in reality, would ATC tell you when to descend, or would you decide for yourself?

Also, how do you figure out the ILS intercept altitude?

Thanks,
boeing247

Does that help? http://www.flightsimaviation.com/rule-of-thumb/11_Descending_Distance_and_Rate_of_Descent_RoD.html
Lou also wrote something on that topic.

The ATC guys have their traffic, control zone and responsibility restrictions, but apart from that, they tend to talk you down around that 3 degree reference line. Unless you are flying a very special plane and setup, you may follow this line. The above rule of thumb describes just that.

However, the ATC isn't a reference for flight planning, so the responsibly to descend (or asking for it) timely and sufficient for your plane's need is the pilot's job. If there was weather on or in the way, the same applies. The communication then sets the marks in controlled airspace.

ATC sees your plane type and GS (groundspeed), so they can do the maths of course (or use software) and see when a nice 3 degree descent path is available for you,  and if it would fit into their plans of seeing you higher/lower at certain waypoints of your flight plan. So you are not always descending towards a destination airport, but also to a certain waypoint and stop your descent there. That's where the formula comes in handy.

You, in the plane, have to check your descent rate against the altered groundspeed from time to time, otherwise you will be too fast on the way down. The descent itself (into lower altitudes) and some changing winds may affect it more or less severely, but in general, your groundspeed gets less when descending, so your vertical speed has to be adjusted and can't remain steady.
That's actually what the VNAV does, including hitting the target (step) altitudes at certain waypoints of the arrival procedure. Yes, it even adds some 'optimal value' calcs to allow idle descents and also optimum speeds on the way up, but that's too fancy stuff for us flight simmers when using FMC-less planes.
However, if you're good at basic trigonometry, you can add it and aim for the speeds mentioned in the plane's manual.

But working that basic way easily allows for flying with online ATC for example. And you won't miss the FSX one at all.  ;)

So you can figure out the whole thing from this.

http://farm8.staticflickr.com/7008/6414452237_db0bf260f8_b.jpg
^^Here, I wanted to be at the pattern altitude for Cairo at 5nm out, so I'm not cutting it close, so thats what I calculated.

Second, to do a proper approach, you should have an approach plate. This give you the waypoints along the ILS glideslope path, andthe altitudes you should be at them. In teh older aircraft, you must nesure the marker be heard at the right spot, and at the right altitude when you hear it (all on the plate). ATC would tell you to descend to an altitude, its up to the pilots to decide at which speed and vertical speed the plane must descend.

Do you know of a site that has approach plates for the whole world, as opposed to just the US and Canada?

Since I fly in real-world, I have a ForeFlight subscription on my iPad, and it gives me all the plates for the United States, for the subscription charge (annual) with no charges to update every 32 days, I have no idea where to find them online. They have Canada now, for an extra charge.

The biggest downside to not using the ATC is that when using real weather, I can't get permission to land at an airport that is currently IFR only conditions only. I just have to come in to land and hope like mad that their are no IA aircraft landing ahead of me to block my landings, causing me to go around. :(

As CoolP has said, Lou gave us some information along the lines of adding more distance to the TOD if you have a tailwind, and (I think) reducing the distance if you have a headwind (step in and correct me if I wrong Lou!). I don't like to reduce the distance because I am always worried that I might be to high when capturing the ILS and GS.

Mark

Markoz wrote on Nov 28^th, 2011 at 1:37am:

The biggest downside to not using the ATC is that when using real weather, I can't get permission to land at an airport that is currently IFR only conditions only.

But if you're using the FSX ATC, it does know that you are flying IFR, right? I mean, if you use it, it actually gave you the IFR clearance.
Haven't used it for years, so I could be wrong of course.

Regarding the winds. Note that the groundspeed of yours is the reference value to determine your rate of descent. By it's nature, it takes the current winds into account and you are of course free to determine a safety buffer for starting your descent.
Winds can change on entering lower altitudes and while the rw guys may take a close look at their forecast data, we flight simmers may just use some extra buffer for determining the right point to start the descent.

Speaking of a 3 degree descent by the rule of thumb, you e. g. would be at FL300 and 90nm out to come in at 0ft. You can add some 10% buffer zone and start your descent at 99nm out, so you can counteract some wind influences.
The trick is to check your descent rate on a regular basis, so don't just start the descent and wish for some luck, but e. g. check it at FL200, 100 and so on. You have to alter your vertical speed either way, which is what a VNAV system does all the time.


701151 wrote on Nov 28^th, 2011 at 12:29am:

Since I fly in real-world

I hope this doesn't come in too offensive, but a few weeks back you even advised people that landing downwind would be a 'favourable condition' for a pilot.  :-?
So please accept my apologies, but I'm concerned about aviation safety now.  :P
[url=www.captainsim.org/yabb2/YaBB.pl?num=1317424001/17#17[/url]]www.captainsim.org/yabb2/YaBB.pl?num=1317424001/17#17[/url]


On some charts sources. The big online networks rely on the free work and/or accessibility of charts, so they offer most of the stuff one needs. This of course includes countries where official charts aren't available for free, so a Google search for IVAO or VATSIM chart sources often enough leads to nice flight sim ones.
The quality often differs of course, from purely user made ones to just some more or less outdated rw ones.

There are chart programs out there, for a sim use. They read the Navigraph data and then generate charts, even allowing them to be customized or running as a moving map. One doesn't need a Navigraph subscription of course, they come with a pre-installed dataset which is ok for the every day flying.
However, a Navigraph subscription isn't expensive, so one could even update the dataset every month if needed. There's a 30 day full trial available here. http://www.aivlasoft.com/products/index.html

For instance, the approach chart looks like this. The red symbol is optional and can follow your plane's position if you like. So it may also act as a training tool.
http://img401.imageshack.us/img401/5134/approach.jpg

CoolP wrote on Nov 28^th, 2011 at 1:54am:

Markoz wrote on Nov 28th, 2011 at 1:37am: The biggest downside to not using the ATC is that when using real weather, I can't get permission to land at an airport that is currently IFR only conditions only. But if you're using the FSX ATC, it does know that you are flying IFR, right? I mean, if you use it, it actually gave you the IFR clearance. Haven't used it for years, so I could be wrong of course. Regarding the winds. Note that the groundspeed of yours is the reference value to determine your rate of descent. By it's nature, it takes the current winds into account and you are of course free to determine a safety buffer for starting your descent. Winds can change on entering lower altitudes and while the rw guys may take a close look at their forecast data, we flight simmers may just use some extra buffer for determining the right point to start the descent. Speaking of a 3 degree descent by the rule of thumb, you e. g. would be at FL300 and 90nm out to come in at 0ft. You can add some 10% buffer zone and start your descent at 99nm out, so you can counteract some wind influences. The trick is to check your descent rate on a regular basis, so don't just start the descent and wish for some luck, but e. g. check it at FL200, 100 and so on. You have to alter your vertical speed either way, which is what a VNAV system does all the time. 701151 wrote on Nov 28th, 2011 at 12:29am: Since I fly in real-world I hope this doesn't come in too offensive, but a few weeks back you even advised people that landing downwind would be a 'favourable condition' for a pilot.  :-? So please accept my apologies, but I'm concerned about aviation safety now.  :P On some charts sources. The big online networks rely on the free work and/or accessibility of charts, so they offer most of the stuff one needs. This of course includes countries where official charts aren't available for free, so a Google search for IVAO or VATSIM chart sources often enough leads to nice flight sim ones. The quality often differs of course, from purely user made ones to just some more or less outdated rw ones. There are chart programs out there, for a sim use. They read the Navigraph data and then generate charts, even allowing them to be customized or running as a moving map. One doesn't need a Navigraph subscription of course, they come with a pre-installed dataset which is ok for the every day flying. However, a Navigraph subscription isn't expensive, so one could even update the dataset every month if needed. There's a 30 day full trial available here. http://www.aivlasoft.com/products/index.html

Several things: first I don't recall sayign that, second, I have lots of typos and things get mixed up as I race to beat somebody to post my idea. Third, thats a terrible idea, and fourth, downwind works in a Rutan plane because it doesn't matter which direction teh things going.

701151 wrote on Oct 4^th, 2011 at 12:38am:

Active runway is based off wind directions, not a normally used runway. If FSX weather sets wind at a heading of 360, then you'll be using runway 180. See, wind conditions at LAX are usually in favor of runways 25 or 24, although they're in the wrong direction for many things, except Asia and hawaii. However, if you set FSX weather to 250 degrees, it'll put you on runway 7 or 6 because thats favorable to the conditions, although its not what's commonly used. another company makes they're stuff right, so trust them.

[url=www.captainsim.org/yabb2/YaBB.pl?num=1317424001/17#17[/url]]www.captainsim.org/yabb2/YaBB.pl?num=1317424001/17#17[/url]

Peter, I think you are the guy sitting next to a pilot (which is flying). Not the one being legally responsible for the flight. Am I wrong?
I doesn't matter much though, but I was surprised about the 'downwind statement' of course. Maybe that's why I recall it.  :) For a sim usage, this is no problem of course. It's just a different beast if I do things right or not so right in my sim, or if I explain certain items to others, mixing them up severely (180 degrees to be precise). But it's a sim for a reason and I enjoy the freedom there, maybe in the same way as you do.

No problem with stating wrong things, but you are sometimes very confident about them, which may distract some other people.  ;)
Blaming some typos when the context is mixed up .. well. Yeah, lets keep it that way since saying 'I was wrong' is a hard thing to do for some.  :)
I've just reacted on the very confident statement of yours I think. Apologies.

Well I'm learning yes, and well, as I said, I contain lots of typos ad jumbling of things in some posts.

No problem with that, Peter. I also notice your positive attitude to help others, which is a great thing. So keep that one up and maybe work on the .. typos.  :)


Your descent plan is a nice thing for example. Maybe you could add your used formulas for others to be able to work out one by themselves.

CoolP wrote on Nov 28^th, 2011 at 1:54am:

...Speaking of a 3 degree descent by the rule of thumb, you e. g. would be at FL300 and 90nm out to come in at 0ft. You can add some 10% buffer zone and start your descent at 99nm out, so you can counteract some wind influences. The trick is to check your descent rate on a regular basis, so don't just start the descent and wish for some luck, but e. g. check it at FL200, 100 and so on. You have to alter your vertical speed either way, which is what a VNAV system does all the time...

This rule of thumb I've learned a long time ago with a friend of mine who was a real life airline pilot. I always use it and it works very well for me (FS purpose). Is the 3x rule and is very easy to use. Just divide your cruise altitude by 3 and the result will be the TOD. For example, if you are flying at FL 300 and the destination airport is at 0 ft, you must begin your descent between 100/90 miles - TOD = [(300-0)/3] - away from your destination, using a descent rate of 1,800 ft/min and IAS around 310/300 knots. If you feel you are descending too fast, reduce the descent rate and/or speed. Remember that below 10,000 ft, IAS must be kept at 250 knots or less, and don't forget to look constantly at your wind vector. Whatever, try to adapt the rule to the aircraft type you are flying.

Pinatubo.

Very good description, Pina. Mind the groundspeed as reference for the VS.
By the way, did I mention that I've found some nice freeware for South America and with a lot of details for Brazil? http://www.fsxamericagigascenery2010.xpg.com.br/ It was a pain to download, but is a fun to fly and explore. And your country offers some nice views and approaches.  :)

im flying 727 with radio navigation only. If i fly to small regional airport with no DME service i just marking the time from last beacon. I convert IAS to TAS by table, so using clock and TAS i know how far me from last beacon. knowing leg length, its simple to find out when to descend. i descending using 3x rule. :)

Windplayer et al, in the real world descent profiles are generally standard at a 3 degree profile to get you nicely onto the ILS or IAP fix, as indicated above the way to work it out is simple, some people use a 4 X profile but the outcome is the same.

Here is what we (I) used to do and what I taught as an instructor and check and training captain for years on a variety of real aeroplanes. Once you understand it, it is actually simple math then it become simple and all the tools you need are in the cockpit- Airspeed indicator, Altimeter, Distance readout (DME or GPS) and an approach chart.

ALT x 3 is distance to commence descent minus the altitude of the aerodrome and or IAF (instrument approach fix) commencement altitude:

EG. Your at F330 the ILS starts at 3000ft and airport elevation is say 100ft. 3x33 =99 nautical miles TOD to go all the way down at that profile, speed is generally irrelevant so you can barber pole or max or stay at a speed profile depends on the aircraft. Slowing down is the issue and you need to slow the descent and go level now and then to reduce speed and then keep descending (in a big and heavy aeroplane that may require a minute or two at level speed to deaccelerate or slow down, then away down you go again,

If the aerodrome your goind to land at is say at a high elevation then you take that off for example, aerodrome is 5000 ft then you actual height to lose from F330 is 28,000 feet, so F280 multiplied by 3 gives you - 84 nautical miles. For all intents and purposes ignore the last 0 on the FL. Remember you need to be ready to go and prepared by looking at the approach etc way before the descent point and then waiting for it to arrive and away you go.

So how do you stay on profile all the way down and as you slow the aeroplane to different speed profiles for the approach and landing?

The answer is quite simply you match your ROD to the IAS - How?

You divide IAS speed by 2 to give you the required rate of descent to stay on profile, hence:

If you descending at 300 kts then your ROD is 1500 fpm
if your descending at 225 kts then your ROD is 1100 fpm
if your descending at 200 kts then your ROD is 1000 fpm
if your descending at 180 kts then your ROD is 900 fpm
if your descending at 150 kts then your ROD is 750 fpm and,
if your at 120 kts your ROD is 600 fpm.

And so it goes.

So all you have to do is change the pitch attitude up or down to keep to or obtain the desired rate of descent.

You can check your profile if you have GPS or DME as you will go through 1000 ft of altitude every 3 nm. So if your a little ahead because of wind then you increase your ROD to stay on profile, or if your getting behind because of a headwind you decrease the ROD.

So you can easily check how your going by taking the distance and dividing it by 3 to find the altitude you should be at with a 3x profile, e.g. at 21 DME or NM you should be at ? 7000 ft. AT top of descent or 99 nm divided by 3 gives? guess what F330.

See how it works, the trick of using ROD to keep on profile means as you reduce speed by the time you arrive at you FAF or commencement of the ILS for example, your on profile and this works for all aeroplanes no matter what type. The great thing about this technique is that you also fly the Instrument Approach the same way by managing your ROD and you will also find that this matches very nicely the ROD or descent rate required for the speed to fly an ILS or other instrument approach.

Hope this helps, happy to put together a quick downloadable tutorial if people really would like this.  8-)

It only becomes a bit of an art form when you want to fly say an non precision approach (NDB) or DME Arc arrival then you need to work back on all the distances including the arc distance to work out your descent point - but that as they say is for another time.

Quote:

Very good description, Pina. Mind the groundspeed as reference for the VS. By the way, did I mention that I've found some nice freeware for South America and with a lot of details for Brazil? http://www.fsxamericagigascenery2010.xpg.com.br/ It was a pain to download, but is a fun to fly and explore. And your country offers some nice views and approaches.  Smiley

Thanks for your nice comment, CoolP. :)


Quote:

im flying 727 with radio navigation only. If i fly to small regional airport with no DME service i just marking the time from last beacon. I convert IAS to TAS by table, so using clock and TAS i know how far me from last beacon. knowing leg length, its simple to find out when to descend. i descending using 3x rule. Smiley

windplayer, actually you are using dead reckoning process to calculate one's current position by using a previously beacon, or fix, and advancing that position based upon known or estimated speeds over elapsed time, and course. Despite the disadvantage of dead reckoning is that since new values are calculated solely from previous values, any errors and uncertainties of the process are cumulative, but it works.

Cheers,

Pinatubo.

Ah, nearly forgot the essence of the thread, ditching ATC. I find FSX ATC to be a pain. The way the program directs you is sometimes bizarre and the descent points and hold ups on the way down are weird and makes flying any sort of climb or descent profile difficult. When you have a lot of AI and a busy terminal area in a big city it really clogs up the system so now I just avoid it unless I feel like being stressed up a bit, but then come to think of it the reason I like flight simming is not to be stressed!

If you like the ambience and simulation fine but as a long time maritime patrol pilot I like being left alone and not being pestered by what we used to call -THE TALKING TRAFFIC LIGHTS, after all we are here to have fun flying the aeroplanes are we not?

What works for me is to start up the ATC dialogue box which seems to fire up AI traffic and ATC then get a take off clearance in the direction I am going then I just go to flight following mode., so I get a little bit of chatter for amibience, frequency changes so I do not have to look them up and the traffic is there as well. I just operate IFR all the way. You can request a clearance later on if you wish for an instrument approach if your following a plan anyway or just go it alone but as MarkOz points out you can get some interesting head to heads sometimes.  :)

AS for FSX ATC well its the pits really, but then so was real life ATC sometimes.

CoastalDriver wrote on Nov 28^th, 2011 at 10:55pm:

The answer is quite simply you match your ROD to the IAS GS - How? You divide IAS GS speed by 2 (and add a zero) to give you the required rate of descent to stay on profile, hence: If you descending at 300 kts then your ROD is 1500 fpm if your descending at 225 kts then your ROD is 1100 fpm if your descending at 200 kts then your ROD is 1000 fpm if your descending at 180 kts then your ROD is 900 fpm if your descending at 150 kts then your ROD is 750 fpm and, if your at 120 kts your ROD is 600 fpm.

Another great post. But I'd make that 'IAS' a 'GS' (for groundspeed) since, otherwise, you will not fly a 3 degree approach but something else in a more pointed angle, especially when starting high, where your IAS reading is low.

As an example, I'm currently at FL330, IAS is 270 kts, GS is 513 and the only speed defining how fast I get closer to my destination is the GS. If the winds change, my IAS will stay the same, but my GS will change, I would have to recalc my VS setting. That's the spirit.

So my initial descent rate would be approx 2500 ft/min (5 times GS or /2 + '0') and not 1350 ft/min (270/2 + '0') as your current text explains it. That's a 3 degree angle with the 2500 ft/min (which we are aiming for) and a 1.7 degree one with the IAS based method. Therefore, you will end up being too high when taking the IAS readout as reference.


To windplayer's and Pina's post. I must admit that I have a ton of respect for the guys really flying the dead reckoning in the sim. It can be very rewarding when the navigational instrument (stopwatch) and an aware pilot succeed on finding the right spot to land or navigate further from.  :)
Even more respect when flying with some rw injected weather.

Cool IP interesting response perhaps I can explain further. Ground speed is relevant as you point out but you manage those variables and the changes of configuration on intial to final approach where you IAS is changing as you slow by using the simple ROD of rule I outlined above. The reason is that wind shifts with altitude and you can go from a headwind to a tailwind and back again during an approach.

As I mentioned in the above posts you use both the distance readout and altimeter check to verify whether your high (it could be because of a tailwind component) or low (because of a headwind component). This is why it is easier to simply change your ROD and manage your speed accordingly than worry about what the groundspeed is doing all the time the aim is to stay ON PROFILE which is the 3 degree slope. In the real world many approaches have altitude limits which make this very trying but that is what flying is about if you would like to have a go at one that has caused more real life problems than any other try the Localiser approach to RWY 33 at CAIRNS QLD where there are a variety of altitude limits and then what appears to be a big steep dive to get to minimums at the end, using the ROD method makes this not so hard after all.

Once you get used to it is easy to manage and a lot less demanding of brain power than worrying about what the groundspeed is because throughout your approach to final landing your flying the aircraft according to IAS on the airspeed indicator not groundspeed.

It is also a way of managing inertia, reducing fuel burn and letting gravity do the work.

Try it out put your self at F330 on approach to an ILS somewhere with nil wind and do the approach, then do it again with a 30 knot headwind, and then again with a 30 knot tailwind.

You can easily see for example on the ILS that if your indicating 180 knots and your rod is not 800 fpm but say 600 fpm that you have a headwind and vice a versa for a tailwind, managing the ROD will keep you on slope all the way.

I can see that I am going to have to do some descents and approaches using IAS. I, like CoolP,  have always based my rate of descent on Ground Speed and not IAS. :-/

Mark

CoastalDriver, could you be so kind and elaborate how IAS should be a valid reference value after TOD, determining the rate of descent to stay on a 3 degree path down to maybe 3000ft, until catching the glideslope there?

I am aware that, to prevent falling out of the sky, you better watch your IAS on final approach. But that has nothing to do with maintaining a proper descent angle those roughly 30.000ft before you can catch the ILS and even thereafter.
I can't, from a scientific viewpoint, follow you and the formulas given when it comes to the descent path and maintaining it.

I've actually showed that your IAS/2 = ROD formula leads to a huge offset with doing the maths for you. So the guys using it will end up way too high when starting at TOD down to their destination. How come? The maths are rock solid, so maybe something else is mixed up here.
Expect me to listen closely.  :)

Well guys - seems I have some of you confused. Let me begin by explaining the first key premise of flying any aeroplane of any type:

ATTITUDE + POWER = PERFORMANCE

This means that for any given attitude (pitch angle) plus power setting you will obtain performance or outcome. This is why jets are very much a by the numbers excercise, you learn the pitch angle plus the power settings required to obtain various speeds/ROC's etc. I have a power/attitude/speed table for all the aircraft I fly as a point of reference and it is the first thing I experiment with when I get a new sim model by going through take offs level flight at various altitudes, turns and descents before I go any further to get some idea of what power and pitch attitudes are required for level flight, climbs, level turns, climbing turns, descending turns and descent and approaches, to work out what is what with each aircraft if the information is not otherwise available.

You will notice with the 707 or 727 for example the initial takeoff pitch attitude is quite high and then is decreased in increments to about say 8 degrees or less in the climb. Your ROC will vary with temperature, weight and power. You will have noticed with the 727 that the flight deck angle or pitch on final at Vat is quite high and even in level flight the aircraft is flying at a particularly higher attitude or pitch angle that a lot of say non turbine aeroplanes. In descent the actual pitch attitude is quite flat without power and it is the apparent angle from the deck that gives a different impression, so generally say like for the 727 on descent using attitude and idle power the attitude indicator is only -2 or so degrees (dependent on weight and temps)

Level flight will have a certain pitch attitude, dependent on wing design, altitude and weight and power.

What we are trying to do here is descend managing the intertia of the aeroplane plus speed, so to obtain a certain performance what do you need to vary? Attitude or power, so it follows that if you are at flight idle (or basically zero thrust), then to obtain a certain performance you need to vary the attitude or pitch angle. Better to change the attitude than to be flogging the engines up and down and burning heaps of fuel in the process, why use fuel when gravity is doing the work for you?

The 3 degree ROD process I have described so far is to allow you to use the inertia and gravity momentum of the aircraft to descend with minimum power. Naturally if the ROD increases beyond reasonable limits you will need to apply or decrease power and change the attitude, so we are using power to control speed and attitude to control ROD and we keep this process going all the way down to touchdown. At the start of descent you lower the nose first, then allow the aircraft to start descending, then bring the power back. There will be level off points where you need to let the aircraft effectively fly level for a minute or two to reduce speed, the more drag the quicker the deacceleration, 707 and 727's are quite slippery or not as draggy so will take longer to slow down, during this slow down point you may need to apply power to maintain the performance you require. You will have no doubt experienced this or recall these phases as passengers in jet transport aircraft. The key to making this all work is anticipation and being ahead of the aeroplane by knowing where your going and at what points you need to slow down and or configure the aircraft. Those points are distance and altitude.

If you try the half the IAS method to manage your ROD you will find that you do have to apply and reduce power now and then but the changes will be minimal and by the time your below 10,000 ft you will generally be using say about 60-70% N1 and as you increase drag by extending flaps and then gear then you will need more power to maintain airspeed and then only have to make minor changes in pitch attitude to control the rate of descent.

Don't worry to much about the changes in speed of IAS v TAS v GS with altitude on the way down, the ASI is correcting this automatically and you have MACH indicator as another reference,  the altitmeter distance check will smooth this out for you and help you increase or decrease the ROD required to cater for changes in winds. You can go as fast as you like as long as you don't exceed the barber pole limits for the aircraft, generally aim to keep speed just below or add barber pole indications until below about F150.

First of all, thanks for the explanations. I wasn't confused at all, that's why I asked again for confirmation/explanation. As it shows, your last post is on another topic, maybe your previous formula was too, so apologies if I read it as the wrong thing.

However, the rather simple and maths proven stuff on determining the TOD and the descent rate necessary to achieve and maintain a 3 degree path may, for example, be well summarized here. http://selair.selkirk.ca/Training/misc/math/get_down.html
As some simple graphics got added too, I hope that the confused guys now can get back to more stable regimes while enjoying the extra reads on other topics from your side.  :)

Here's one on the approach portion. http://www.navfltsm.addr.com/gs.htm

As a side note. The FMC equipped and 'VNAV' able birds don't calculate their stuff that simple of course. Their advantage comes from calculating optimal values in regard to the current conditions, which for instance takes ISA deviations into account.
That's the reason behind the data entries on the descent page by the way. The winds and the planning for when anti-ice is on are vital when it comes to planning an optimal descent path, taking the higher idle from anti-ice stuff into account for example.

The same goes for the winds. They affect groundspeed (GS) and therefore alter the descent angle if being left uncorrected. Which then leads us back to the simple dependency of the vertical speed (VS) needed in regard to the groundspeed (GS) of the plane. Otherwise you under- or overshoot your end of descent point because you've left the pre-planned path.

So either have a smart FE on board or an even faster VNAV computer, getting the right source data from his pilots. Last step is mandatory, at least in the rw.

Cool IP et al, no worries, I never had the luxury of flying aircraft with advanced computer control systems and you might say I like LOU are from that era when most aircraft were developing into what they are today, that is autopilots were simple systems (like the 727 and 707 here), there were no engine control computers, no angle of attack indicators and no EFIS systems. My last flying was in a big heavy turboprop and it was very much a hybrid machine and reflected its design age. Which is why a lot of guys struggle to understand the 727 and the 707 because it takes you back to the beginning of the jet era and a lot of this sort of stuff had to be thought about by the pilot and managed properly particularly with swept wing turbine aeroplanes.

I used and taught the 3 degree profile system for years and probably because of that I am comfortable with the concepts and the need to keep it simple, after all it is really about geometry at the end of the day. I have lost count of the number of professional pilots I saw struggle with the ILS who would chase the ILS all over the place rather sticking with and understanding the basic relationship between attitude and power. Really it is about just finessing the flying by always flying an attitude first second and last. What you see on the AI is what you should see outside that is all, the trouble is that jets by and large because of the wing design, flaps etc, end up with quite high nose attitudes and when your at the end of that long lever (the fuselage) it is easy to be deluded by what your seeing as opposed to what the aeroplane is doing and showing by the instrumentation.

Anyway have a go at the method I have described, you will find with a bit of practice and it does not come automatically by the way, you will fly a lot smoother and be ahead of the aeroplane all the way, then you can really enjoy the challenges.

I might add that returning to topic about ATC, the FSX program either starts you down much to early or late and then will hang you up about half way down which makes the last descent segment really difficult, in real life ATC will be expecting you to fly the standard 3 times profile and thus not be asking you to slow down, speed up or having you stuck at a certain altitude, so it works a lot better. That is one of the reasons why I use flight following in FSX and generally forget about full ATC control as it just stuffs you around for no real good reason and you can't do things like fly a holding pattern or other manouevres as they are not programmed into FSX.

Anyway have fun.

My apologies if this has been answered, but I haven't had time to read through all the posts. Where on a chart can I find the ILS intercept altitude? And is it always the same in reality as it is in the sim?

Boeing 247 the ils interception point is always at 10nm which you will find marked on an ILS approach plate on the vertical profile for the approach shown on the bottom of the chart. Generally it is at 3000 ft AGL however there are some ILS approaches that are steeper at 4 degrees but they are catered for by giving you a glide path signal further out but these are rare. There are a lot of ILS where you intercept the glide path at 7 nm or abut 2100 -2500 feet and some further out at 13 or even 20nm at a higher altitude, generally the reasons for these approaches is do with the siting of the ILS equipment on the ground at the airport. You will note from looking at a lot of the charts that for most ILS's there is a NDB or locater beacon at the beginning of the ILS which you have to tune up using your ADF and this will give you a positive fix when you pass it if you do not have DME or it is not a co-located with the ILS and not all are. They are also very useful to track to a point to pick up the ILS but generally have a very short range of only about 20 nm.

AT 10 nm if your on the localiser the vertical beam of an ILS the vertical ILS needle and the glide path needle will be centred as well. In my flying you should be at final approach speed at this point and this point was time for gear down and minimal flap changes until past the check height shown by the maltese cross on the approach plate, flying the profile and being configured means you can make minimal attitude changes and power changes and basically slide on down the ILS to minimums.

You will note that you can pick up the localiser beam well before the glide path beam and the ILS needle will be indicating fly up or be above the centre until you hit the 10 nm point when the both centre and then you merely follow the commands indicated, needle going up means fly up, needle going down fly down, needle left go left, needle right go right. Be aware however that this all changes once you start to go past the end of the runway and fly away such as in a go around when the needle sense becomes reversed so if it indicates to the left you go right etc.

Hope this helps.

While that does help somewhat, I wouldn't think that pilots fly up and down until the G/S indicator shows they're at the correct altitude. Where can I definitively find the correct altitude to intercept the ILS? For instance, on the chart I've attached, is it at 10,000 or 8,000 (I would assume 8,000).

Oh, and CoolP, earlier you mentioned the AivlaSoft Electronic Flight Bag software package. Were you saying that you need a monthly subscription to keep using it?

Thanks,
boeing247

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Boeing 247, your correct about not chasing the glide path and thinking about be at a steady approach attitude to intercept the ILS (localiser path and glide path or vertical and horizontal displays on the ILS gauge). The approach you posted is a little tricky but let me see if I can give you a simple explanation using the Capt Sim 727.

The ILS is 111.55 so you would set this on nav 1 and set your course indicator on the HSI to 260 degrees the ILS localiser course. As it is an ILS/DME you should get a DME readout from about 20 nm from the station or location of the Denver ILS for RWY 25. The 10,000 ft altitude shown on the plate is referenced to being at 14.8 DME (little box) and the altitude has a line underneath. The line underneath the altitude always means a 'not below altitude', you can be above 10,000 ft but never below to remain safe, so in this case you would not be below or be at 10,000ft intercepting the localiser at 14.8 DME. You would then fly in or track 260 degrees your vertical needle centred and be able to commence a descent to 8000 ft and not be below 8000 ft at that altitude until when and you do intercept the glide path (needle alive or starting to work wait until it centres on your HSI and then follow the glide path commands to continue descent on the ILS, noting again that you must not be below 7000 ft at 4.7 DME and then continue the descent to your minima on altimeter of 5552 ft or 200 ft which is the minimum height you can descend to in instrument conditions and if your not visual at that point then you go around following the published track which in this case is 260 keeping you over the runway as you climb out and your turn commences when you intercept the 306 radial from the Falcon VOR 116.3.

Looking at the chart and interpolating it would suggest the glide path will appear at about 8-10 DME or one third of the distance between 4.7 and 14.8 DME from the 111.55 Denver RWY 25 ILS.

Note that you can reference the location of the beginning of the ILS when you cross the 043 Radial of the Falcon VOR and the check height fix of 4.7 DME when you also cross the 002 Radial from the Falcon VOR and then use the same VOR to intercept the missed approach track which is the 336 radial of the Falcon VOR. This is for a localiser only no DME approach.

So here is how you would do it, you would have Denver ILS on NAV 1, HSI cursor set to 260 and Falcon VOR on NAV 2 and the indicator on the panel for NAV 2 set to the VOR setting and it will give you the picture with the needle pointing to the station and the tail of the needle moving up and the away as you cross the 043 R then the 002 R then the 306 R. You will get the standard glide path localiser indications and a dme readout in the dme counter window on the bottom left and the HSI.

So you would concentrate on the AI and HSI to fly the ILS, with a nice standard descent profile of say about 150 knots (about 750 FPM ROD)  noting the altitudes of not below 10,000 as you reach the Falcon 043R on the secondary nav display shown by the needle, the continue descending to 8000ft at which point you will get the glide path indicator begin to centre itself then continueing the descent following the glide path needle as a command instrument (fly up or down) to not below 7000 ft until you reach 4.7 DME and then continue on descending as your slowing to Vat say about 130 knots (only 650 fpm ROD) to the minima (NOTE: YOU SHOULD HAVE YOUR RAD ALT SET TO A 200 FT DH) then land or power up, gear up and then climb out as your retract the flaps if your going around.

The reason for the references to the RADIALS based on the Falcon VOR is that this is also a localiser approach and you could fly a localiser approach, that is there may be no glide path available and or your aircraft may not have DME by tracking 260 and then using the radial crossing points to positively fix your position and hence from the chart you would know your distance as for example if your on the 260 localiser and your crossing the 043 Falcon radial you can only be at 14.8 NM or the position shown on the chart. It is what is known as a positive fix or the intersection of two position lines.

As you can see they put a lot of information on these approach plates and some have a dual purpose.

If I could do videos I would put together a visual example for this approach using the Captain Sim 727 but of that process I am ignorant I am afraid.

Hope this helps you understand what is going on here for this one. As you can see it is one of the reasons in good crews and procedures you will review the approach and really study it well a good 10 minutes before the top of descent point you have it all squared away before you begin the approach and you know what your doing in advance. In two pilot crews the Pilot Flying will brief the approach verbally aloud to the pilot not flying and by doing this you cross check your understanding of what the approach involves how your going to fly it and what your going to do if it all goes pear shaped at the end.

boeing247 wrote on Dec 3^rd, 2011 at 5:41am:

Oh, and CoolP, earlier you mentioned the AivlaSoft Electronic Flight Bag software package. Were you saying that you need a monthly subscription to keep using it?

It comes with a dataset, so you get a complete setup. I would have to check which actual date it delivers, but lets assume some 2011 data, I think 1101. So the monthly subscription is optional, like on the CS FMC planes.

It's not that cheap, so the trial period really is recommended. The screenshots alone can't show the potential it has, but running it besides FSX on your own PC may do.

You guys *really* need to go online. FSX's ATC is nothing short of a joke  ;D

Join IVAO or VATSIM, talk to real ATCs (well, at least real people) and enter a whole new world in simulation. After 2600 hours online, i just can't fly offline anymore  :D :D :D

Some are real pilots and real ATCs, so you can expect a high level of communication language and procedures and learn from it.

Hi NamCo, I know this is getting off topic but I guess you would need a mic/headset arrangement to do this and what is the load in terms of internet data and time, the reason I ask this is I like the idea (I mean if someone wants to do ATC instead of flight simming sounds fine by me) but I have to rely on a digital 3G mobile internet modem because I live in the country and have no landline or cable access available and while my speeds are fine I am severely limitd by download capacity in terms of my telco's limiting or capping my monthly limit (MarkOz will be familiar with the sorry state of internet and broadband outcomes in OZ) and I cannot change what they give me so I would not want it chewed up with a couple of hours on VATSIM for example. Any ideas what the internet data demands are for VATSIM?

Still off topic. Going by what CoastalDriver said, I'm lucky because do not live too far out in the country, about 100 kilometers from Melbourne, and we have a very fast (30Mb/sec) cable network with their plans getting better all the time. I have friends who live 20 kilometers away who get charged huge amounts for small download limits. I consider myself lucky because the company picked our city to install cable.

As for IVAO or VATSIM, I doubt I would be able to pause FSX in mid flight (not that you can pause it anyway) if I found I really needed to. I have too many bad pain days to allow me the joy of flying without taking a break now and then. ;)

Mark

Yeah I forgot about the pause while I boil the kettle, make a cuppa, answer the phone then unpause to keep going. With ATC guarantee the moment you hand over to the autopilot they will call you and when you cannot respond. This invariably happened when I would be mid flight across the Pacific and come back to find the ATC window open and a lot of dialogue finishing with flight plan cancelled however flight was proceeding merrily so I leave it that and if I want reactivate the plan before top of descent, only trouble is the GPS can never reload the plan and pick up where you are in terms of the plan and always insists on giving your readings from the start of the plan and that is a real pain if you have the nav following GPS.

Think I will keep to flight following as I do now, too much trouble to do the other stuff.

Yeah, with a 3G connection it's hard to maintain a stable connection for the required amount of data. You don't REQUIRE voice, but it's much easier and more "professional" like that.

You cannot pause online, well, at least you shouldn't, not for more than 5 minutes. As for pause on TOD or similar, the same applies - And if you're under ATC control, you have to be there and you simply cannot pause.

I guess i didn't remember all of that  ;D

They have a 25% discount for Aivlasoft EFB now. Just sayin'.

Markoz wrote on Dec 6^th, 2011 at 12:59am:

Still off topic. Going by what CoastalDriver said, I'm lucky because do not live too far out in the country, about 100 kilometers from Melbourne, and we have a very fast (30Mb/sec) cable network with their plans getting better all the time. I have friends who live 20 kilometers away who get charged huge amounts for small download limits. I consider myself lucky because the company picked our city to install cable... Mark

Mark, excuse my asking, but how much do you pay to get your 30 Mbps? For the comparison my 20 Mbps cable connection here in Rio de Janeiro, costs about US$ 100.00 per month.

Pinatubo.

Here in Portugal i am currently on a new ISP (Vodafone) which charges me €36.99 in the first year and €42.99 from then on for free phone, 70 tv channels and 50/5Mbit internet.

Previous ISP charged me €59.99 for the same stuff exactly  :P

Pinatubo wrote on Dec 6^th, 2011 at 10:25pm:

Mark, excuse my asking, but how much do you pay to get your 30 Mbps? For the comparison my 20 Mbps cable connection here in Rio de Janeiro, costs about US$ 100.00 per month.

It depends on the download allotment. I'm paying $AU80 a month for 120GB of traffic (upload and download) per month. They have just been "bought out" by a larger ISP Company and I will soon be paying $AU70 400GB per month at 30Gb/sec.

The second part to all this is that it is split in two. 60GB during peak time 7am - 1am and 60GB for offpeak time 1am to 7am. Our slow down for exceeding our limit is 64Kb/sec.

There are better plans for less out there, but they have not been fully introduced to where I live. Once they are, I might switch.

The big downside to my broadband is that we have 4, sometimes 5 (a laptop), computers using the one internet connection through a router. I have 2 adult sons still living at home who spend most of their time playing multiplayer games online all day. Plus the fact that I download a lot of files when I need drivers for computers I fix. It all ads up. We usually manage to just stay under our limit, but once every 4 or 5 months, we exceed it and get a slow down for a day or two. So our internet, at present, is borderline enough. It should be plenty once we start the new plan, but like most others times, we get more so we use more.

Mark

Nuno and Mark,

Thanks for the feedbacks. For comparison, my ISP (Net-Virtua) charges me about US$ 100.00 monthly to get 20 Mbps, 100 GB (traffic limit) internet, plus 120 cable TV channels. No phone included.

Pinatubo.

Pinatubo wrote on Dec 8^th, 2011 at 1:52am:

Nuno and Mark, Thanks for the feedbacks. For comparison, my ISP (Net-Virtua) charges me about US$ 100.00 monthly to get 20 Mbps, 100 GB (traffic limit) internet, plus 120 cable TV channels. No phone included. Pinatubo.

I did have their Pay TV, but I dumped that a few years ago when they changed it too much and it suddenly started costing us a small fortune to keep. Our home phone is VOIP through our ISP. The service and phone calls are quite cheap compared to a normal phone line.

Mark

Geez, you guys have unbelievable download capacity, because I am in a rural area with no landline we are stuck with mobile 3G modems, capped at 15GB per month and that is it, even if you wanted to pay for more they wont give it too you, gets me cranky I can tell you. So we have two carriers so we get at least 30 GB per month, but the problem is we use the computer for internet TV and it burns through the download very quickly and my prediliction for some big sim files now and then. Fortunately just using the FSX and REX does not demand much.

I am envious. Bring on the NBN, but I can guarantee it will never happen for us, unless we pay. Telstra wanted $30,000 to put a line in. Told em forget it. Then they turned up last month wanting to put an optic fibre through our property to their towers on a hill nearby (not my place), told em yeah sure, put our line in for free or forget. Have not heard from them, hope it costs them a couple of hundred grand to do it because they are not coming through our place for free, what a cheek.

The approach plate for an ILS is the way to go, and of course, a legal requirement for real world instrument flights.  I have access to terminal procedures through membership to the Airplane Owners and Pilots Association, but for simulation I sometimes just "wing it" to expedite landing at an airport I don't want to to take the time to download or look up.  The following works good for me when I am not trying to exercise real world proceeedures and should work adequately for those without access to approach plates:

Look up destination airport on the FSX map.  Note the airport winds, field elevation, and ILS equipped runways.  Select a runway taking best advantage of winds and note the localized frequency and approach course.  Also visualize an intercept course from current location to the beginning of the ILS course shown on the map.  Exit Map and return to flight, then setup localizer frequency and course.  Turn to intercept the localizer and navigate to around 2500 feet above field elevation (terrain permitting, otherwise adjust as needed)  Adjust intercept course enroute as needed (if GPS available, use as self-contained radar vectors to intercept point) and slow to approach speed.  Intercept localizer and turn on approach course.  Watch for glide path cues to become active and aircraft below the glide path.  Continue approach with normal ILS procedures (including intercepting the glide path from beloe) to landing or missed approach.

Happy flying,
GW

gallen144 wrote on Dec 8^th, 2011 at 2:48pm:

Look up destination airport on the FSX map.  Note the airport winds, field elevation, and ILS equipped runways.  Select a runway taking best advantage of winds and note the localized frequency and approach course.  Also visualize an intercept course from current location to the beginning of the ILS course shown on the map.  Exit Map and return to flight, then setup localizer frequency and course.  Turn to intercept the localizer and navigate to around 2500 feet above field elevation (terrain permitting, otherwise adjust as needed)  Adjust intercept course enroute as needed (if GPS available, use as self-contained radar vectors to intercept point) and slow to approach speed.  Intercept localizer and turn on approach course.  Watch for glide path cues to become active and aircraft below the glide path.  Continue approach with normal ILS procedures (including intercepting the glide path from beloe) to landing or missed approach.

This is the method I use for any aircraft that doesn't have an FMS. It works great too.

I don't have access to charts, so I use FSC9 to give me some idea on what I need to do. I also add the default FS GPS to most of the aircraft that don't have it, so I can get a lot of info from that. I still have to use the either the FSX Map or FSC9 to give me the runway heading for ILS approaches. I nearly always have FSC and FSX running together. I use ASE for weather, so I look at my destination to see what the weather is there. I'm still learning to not ask for landing instructions from 30 miles out, because the ATIS and control tower seem to have different weather to ASE until I'm about 15 miles out.

Mark

Agree I use FSX the same way for places I don't have charts for and to work out what is what, very handy. I really would like some enroute charts for here and there but alas apart from the US ones (which by the way will cover most of the world in generalised detail) I have not been able to find others in paper that I could use here when simming.

I do have links I coul post for Australian, French, US and Japanese Charts and a lot in Europe as well,  some like the Europeans and Japanese you have to create an account to get access but no payment is required, the FAA stuff is free for the US and all US Territories, same with the French and European stuff, not that I have used it much but it was handy for Tahiti and places like that in the Pacific. I can't get the Pacific Region because most of those countries charts are issued by the NZ CAA and they are strictly subscriber and pay, not that it matters much as you can always get the ILS frequencies, runways and approach course out of FSX but not other approaches bit of problem though for a place like Canton Island in Kiribati which only has an NDB approach. I fudge it for those places and give myself a GPS designed ILS approach and watch the radar altimeter like a hawk, after all no point in crashing then starting all over again after hours across the big pond.