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dolin

Top of Descent

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Hi there, I use Radar Contact with the fantastic PMDG 747, and they work together more or less flawlessly;However, one thing happens that bothers me: as you may know the PMDG 747 tells me the optimal point to begin descent via the Navigation Display, and to descent I just input the desired altitude below the current flight level and at the T/D the plane automatically descents. This is the way things works in the sim without ATCHowever, I use radar Contact and they tell me to descent to a particular altitude well before the T/D.In the end it doesn't change much for me; but I need to know when I will start to descent: first because I use FS2Crew and I have to do a few things right before descent, second because airlines in real life ask ATC permission to descent when at T/D (I'm pretty sure, I watched the fabolous ITVV Virgin Atlantic video)I already asked at PMDG, and they told me to come here and ask youThanks for any help!

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Hi there, I use Radar Contact with the fantastic PMDG 747, and they work together more or less flawlessly;However, one thing happens that bothers me: as you may know the PMDG 747 tells me the optimal point to begin descent via the Navigation Display, and to descent I just input the desired altitude below the current flight level and at the T/D the plane automatically descents. This is the way things works in the sim without ATCHowever, I use radar Contact and they tell me to descent to a particular altitude well before the T/D.In the end it doesn't change much for me; but I need to know when I will start to descent: first because I use FS2Crew and I have to do a few things right before descent, second because airlines in real life ask ATC permission to descent when at T/D (I'm pretty sure, I watched the fabolous ITVV Virgin Atlantic video)I already asked at PMDG, and they told me to come here and ask youThanks for any help!
you can always ask to descend early. just request a lower altitude.if rc asks you to start down too soon for your fmc, choose the option for a "pilot's discretion" descent.either way RC has you covered.

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RC calculates its descent position to have you at 11,000 or 12,000 feet about twelve miles out linearly to meet its crossing restriction. On the response there should be (in 4.3) a pilot's discretion option I believe if you wish to delay the descent. You will still need to meet the rest of the altitude clearances.To meet using the FMC an earlier descent you should find on the DESC page a Descend Now function but it will join eventually the constant descent vertical path. The FMC is set up for a constant descent procedure to destination or a fix with altitude constraint you can specify on the LEGS page and thus will differ. Just pick a fix about 40 nm out from destination. To make the FMC descent to a fix be sure to go to the DESC forecast page and enter wind, etc., conditions. Here's what I do on the 737NG:1. I enter a range ring by using the FIX page using the airport ICAO ident and for the fix location /40. On your ND you'll see a dotted line around the airport.2. Once I start getting descent altitude clearances I revert just to HNAV. I then place the commanded altitude in the MCP ALT window and use the MCP FL or ALT CHG command to initiate the descent. I keep an eye on the descent arcs and the N1 speed which should be giving you a near idle descent. The LEGS page furnishes the recommended IAS and I can use MCP V/S if need be to adjust descent rate which also affects the throttles if necessary. Please note that RC may clear you to a lower altitude before you reach the last commanded altitude.3. On the issuance of the crossing restriction (sometimes clarified by "I need you at . . .") at 11,000 or 12,000 (it can be at flight levels instead) I initiate the descent as in two but pay attention to where the descent trend arcs appear in relation to the 40 nm range ring insuring they stop just before reaching it. I often slow in the last few miles to about 280 knots IAS in preparation to the reduction to 250 IAS at and below 10,000.4. Expect a limitation of 210 or 230 knots IAS within 30 nm of destination. This is the restricted traffic pattern speed.5. Once you are handed the runway and initial approach vector you have to option to follow your FMC approach (STAR) and final by then requesting an RC IAP then specifying the runway and you are on your own without monitoring by RC. RC will just advise the final intercept altitude and you next contact will be with tower. If you do include the STAR be sure the earliest fixes outside of 30 nm are in your flight plan presented to RC. If you still want vectors from RC but wish to follow your own vertical path then before activating your flight in RC click on the Controller page and select NOTAMS for the destination. (You can do this with the departure as well.) In this case approach altitudes become advisory and you vertical path will not be monitored. You still will have to follow HNAV as issued by RC. Once on approach when is starts vectoring I use MCP HDG to comply. I also do one item on the FMC ARR page and that is to select for arrival the proper final approach on the right hand side of that page for final. This puts intercept and follow altitudes of the extended navaid/runway extended line on the ND so I can adjust as necessary on final intercept speed and altiude (using V/S) so I'll make the intercept altitude as indicated. Even under manual control I'll do this as it provides a situational wareness at destination.Suggestions:If you think your required descent prior to approach is too steep request from center a lower enroute altitude before given your crossing restriction. Know your enroute MSA. Charts are always advisable.As you get toward final use your TCAS to be aware of aircraft entering final so you can adjust speed to maintain separation from the aircraft ahead of you.In your FMC before TOD enter the expected runway and STAR if used. You can always change these later.Speedily change your aircraft control as needed and then ack the RC command. If you don't ack an RC instruction before a checkpoint you will not get credit for it and RC will give you vectors to turn you back to crossing it. Further out if time allows you can go the the extended menu and request direct to a checkpoint.Remember that ATC rules and not the FMC. The FMC is just an assisting tool.Hope this helps.NOTE: I did not see jd's reply before I posted but I think you'll find some good information here :)

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Have you remembered to take over the comms from Otto?Only then will you get Option 3) to ask for a pilots discretion descent.

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I'm sure I'm not giving away any secrets when I say that the ToD calculation in RCv5 is now very close to the FMC's one. Well, that calculated by Project Magenta anyway. On some occasions it comes slightly after the FMC's. :(

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Morning Ray.A bit nippy down your way today.I'm hearing -14C on the ATIS for Manch this morning.I believe Woodford is -16C.A balmy -6c here.I find the PMDG 747's FMC almost in tune with RC4 most times.Other aircraft want to stay higher much longer.I just ask for the PD(which you don't always get of course.in which case try a 400 foot per minute descent)and when asked to get to 12000 go for option (6) "Unable".You will always get relief.As before with PD you need to be on the comms by then.Doing this you can follow your STAR even for a "far side" approach.And be far higher than RC would initially have you

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Morning Ray.A bit nippy down your way today.I'm hearing -14C on the ATIS for Manch this morning.I believe Woodford is -16C.A balmy -6c here.I find the PMDG 747's FMC almost in tune with RC4 most times.Other aircraft want to stay higher much longer.I just ask for the PD(which you don't always get of course.in which case try a 400 foot per minute descent)and when asked to get to 12000 go for option (6) "Unable".You will always get relief.As before with PD you need to be on the comms by then.Doing this you can follow your STAR even for a "far side" approach.And be far higher than RC would initially have you
Hi Chris,Yes, it was the coldest night for nearly 30 years around here although my personal weather station recorded a low of only -11.1C. :( A little hint. You can repeat as often as you want for PD and eventually RC will relent. My record was about 11 times in testing. :( Also, RC will be happy with a descent rate as little as 100fpm if you want to stay as high as possible for as long as possible. I tend to stay with RC for APP rather than my own STAR during v5 testing but that will be varied as required. Your STAR workaround might not be needed for v5.Going to be colder still tonight. Already -6.8C here and -10C at EGCC. :(

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Hi RayThanks for that tip.I've never tried it so I'll give it a whirl next time.I've got the ATIS on here too.Woodford was a touch colder than Manch last night I noticed.My minimum was -6c.Quite a difference but I'm on a sandy hill.The colder air rolls down into the valley!

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First, thanks to everyone for the replies

Have you remembered to take over the comms from Otto?Only then will you get Option 3) to ask for a pilots discretion descent.
Aha, there it was. I missed that because I like very much the copilot feature and I use Otto for almost the whole flight. Thanks for the tip.
Suggestions:If you think your required descent prior to approach is too steep request from center a lower enroute altitude before given your crossing restriction. Know your enroute MSA. Charts are always advisable.Speedily change your aircraft control as needed and then ack the RC command. If you don't ack an RC instruction before a checkpoint you will not get credit for it and RC will give you vectors to turn you back to crossing it. Further out if time allows you can go the the extended menu and request direct to a checkpoint.
Please, can you better explain these two?Thanks again!

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"If you think your required descent prior to approach is too steep request from center a lower enroute altitude before given your crossing restriction. Know your enroute MSA. Charts are always advisable."By requesting a lower enroute altitude from center before you get to about eighty nm out you reduce the altitude change necessary to get to your crossing restriction of FL120 or FL110 (11,000 or 12,000 feet if below the transition level). You just need to be aware of the MSA or minimum structural altitude in your path to avoid terrain obstacles. Another thing you can do is before you push the start in RC go to the controller page. For the destination airport check NOTAMS. This lets you adjust altitudes (but not course) on your own without RC complaints after the crossing restriction. RC will announce when you can do this by announcing you are responsible to for obstacle clearance. In the early part beyond the crossing restriction this lets you go to a lower altitude than advised so later in the approach your pattern entry will not be as high. I'm attaching an image of a approach plate showing the MSA within a twenty five mile radius of a navaid near the airport. Frequently the MSA circle is broken up into section that show different minimum altitudes according the the direction you are arriving from. The approach plate also shows the minimum altitude within ten nm area of a point on the airport. The altitudes on the vertical profile are along the specific display path only with a margin of a feww hund4ed feet to either side. All of this lets you know how much leeway you have in deviating from the approach controller's assigned altitudes when you have selected preflight NOTAMS for the airport and you have been advised they are now in effect."Speedily change your aircraft control as needed and then ack the RC command. If you don't ack an RC instruction before a checkpoint you will not get credit for it and RC will give you vectors to turn you back to crossing it. Further out if time allows you can go the the extended menu and request direct to a checkpoint.Please, can you better explain these two?"If you have the comms and you cross a checkpoint while RC is waiting for you to acknowledge an instruction RC will not give you credit for crossing that checkpoint. It will effectively stall. Once you acknowledge it will think you have missed that checkpoint and start giving you vectors back toward it finally telling you to resume your own navigation at which point you fly directly to it. When ever you get this if it is safe you can tell RC to skip this "missed" waypoint by going to the extended menu (usually option 9) and selecting Direct Checkpoint and then choosing from the list the point you wish to fly to directly from where you currently are (present position) and RC will clear you to it. RC displays a heading to it in its status window.There are busy times during departure and approach when checkpoints are close to each other and you are managing comms and the aircraft that this might occur. To request a "Direct To" it will not show on the menu unless you have the comms.Thanks again!
I am attaching parts of the ILS 6 for LIEO Olbia. This is a typical example where the approach plate has a 10 nm radius limit to stay within on the ILS approach. I am also including the vertical profile. Note the obstacle altitudes in it and the minimum (underlined) altitudes along the path. There is also in the first image the safe minimum altitudes around the VOR in this case right on the airport.I am also attaching a slightly different example to MKJP as a VOR approach. In this there are to the east higher terrain obstacles and the approach circle is a twenty miles radius to stay within. Note the spaced out high obstacles to avoid and the altitudes on the DME arc before entering the final portion. I am also attaching the vertical profile showing the minimum altitudes on the extended final.All of these show you what are safe altitudes to deviate from RC instructions when NOTAMS are enabled.I hope this explains things better for you.In the RC 4.3 manual tutorials there are examples of approach plates and how to interpret them. Here is a link to VATSIM provided approach plates for some Italian airports. The data in them is newer than the frequencies in the FSX provided scenery so frequencies might differ. (This is not the example of LIEO I provided but should be similar.)http://www.vatita.net/?dir=download&pa...planning/charts

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