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Virgin_A340

40nm crossing point question

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Hi.Trying to get the hang of using the FMC with RCv4 for descents. When RCv4 uses the point 40nm from destination for crossing restrictions (FL120/FL110), is the point 40nm from destination along the flight plan or ijust 40nm from destination "as the crow flies"? Sorry if this is a stupid question! :-shy CheersAndy S

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Andy,Mike's correct. You may find it helpful to include a waypoint in your plan that's 40-45 miles away from the destination airport to ensure you meet that restriction. When you get your clearance down to FL110/120 just enter the speed/FL into the FMC for that waypoint.If your FMC also has a FIX feature you can enter a 40 miles fix for the arrival airport. This draws a circle giving you another check of distance but the waypoint fix is your best bet.

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Hi.Thanks to both of you for your help.For boeing type FMCs do you enter that like "EGLL/+45" for an approach for LHR? I should really reread the FMC manuals that I have I guess!Andy S

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No, you would not use this type of waypoint creation because it calculates along track distance rather than straight line distance (actually EGLL/+45 will create a waypoint AFTER EGLL - to make one before EGLL, you would use EGLL/-45)To get the green 40 mile circle around the airport, you'd go to the FIX page, upselect EGLL, then type /040 to create the circle at 40nm. I normally would also insert a /010 circle so you know where the 10nm circle is for final landing purposes. Since there is a remaining cirlce which can be inputed as well, I normally do the ToD = 3 x FLs to drop + 20, to get a rough circle of which I think I should need to start down. The second FIX page can be used to enter any additional circles required for STAR considerations.Subs

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Hi.Subs, FIX is a good aid but how do you add an actual point into the FMC flight plan so that you can add alt and speed restrictions and use the VNAV for the descent?Andy S

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You can add the waypoint as you suggested ie "EGLL/-45". Remember it's "-" though. Minus for before the waypoint, and plus for after it.Once you've got the dashed green line at 40nm, use the nearest waypoint to the line to create the point, in which case, for Heathrow it might be one of the holds or another waypoint rather than EGLL itself.

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>Hi.>>Thanks to both of you for your help.>>For boeing type FMCs do you enter that like "EGLL/+45" for an>approach for LHR? I should really reread the FMC manuals that>I have I guess!>>Andy SIt depends on which Boeing FMC! ;-)Using the FIX page on the PMDG744, I found that you enter the destination as the fix, in this case EGLL. You then enter /45 which creates a 45nm circle around EGLL. You then press the LSK corresponding to the /45 and it will create a FIX that lies 45nm from EGLL along the route of flight. You then up-select that fix into your legs page and you have just created a precise point, along your FMC-defined route, that is 45nm from EGLL. Now - with the LDS767 FMC - the same procedure will sometimes create a waypoint that lies 45nm BEYOND your destination. -michael

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Hi.Thanks guys I'll give those a try when I next fly.Michael, those are the two I use most often. Also PSS T7.Andy S

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