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makraan

One for the FMC die hards

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Fellow pilots,Here's one I can't seem to figure out today. Not even sure whether it's possible at all but let's give it a shot:On my way to the arriving airport, I'm on heading 130 to VOR ABC. The VOR is located on the field but 10 miles before x-ing I wanna go down wind on a heading of 200. Programming the FMC with ABC310/10, which gives the reference point ABC01 on the FMC. But now I want to program the next waypoint, let's say 10 miles out of ABC01 on a heading of 200. From there to base and finally to the rwy extension point for runway 02.Anyone who can get me on track here?Thanks and regards,Michel

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Ummm, yeah, ok.Once I hit the last waypoint, if I don't have STARS, I follow ATC instructions or I hand fly it onto final and then re-engage autopilot and autoland.ATC will always give you a direction to approach from.ie. left downwind, straight in, right downwind, etc...Goran

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Michel, Tried the same thing, I'm not a pilot nor a FMC guru. The only thing I can recomend is to get a bearing/dist for the second wypt from ABC for your wpt and enter it as accordingly. I could also see that this MAY be a programming option (FMC wise, real) but to do this in FS would bring about a boatload of code.... And well...nuf said Regards,Roman(KGRB)http://home.new.rr.com/spokes2112/images/Image2.gif

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Thanks Goran, but that was not the question. I know it must be possible to create a second user defined waypoint after creating the first. The first waypoint should be used as reference for the second one, yet to be created although I can't find out how. "Logics" tells me that, in my example, the line in the scratchpad could be as follows: ABC01200/15 in which ABC01 is the first user defined waypoint, 200 is the heading from that particular waypoint and /15 is the distance from that waypoint. However the FMC mentions "not in database".Maybe some real drivers or FMC-experts can join in?Thanks,Michel

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There are only two ways that I know of that you can do this one is to write a STAR for it(Don't hold me to the syntax it is from memory), it would look something like this ...FIX ABC01 INTERCEPT RADIAL 200 FROM ABC01 UNTIL 10 FIX ABC02... where ABC02 is the next point you want to intercept, I would assume a point on your upwind leg. The other way would be to do it the old fasioned way and break out your charts and figure out an intersection in the general area and plug that data in to your FMC. As was already posted, if you are not on a published STAR then you are probably under RNAV so you will be getting your directions from ATC.

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you can only create a fix from a radial of a VOR, NDB, Airport or Fix in the database, not from an existing radial fix.so you have ABC01 (10nm, on 310 radial), from this point in an airliner you would normally fly an arc rather than a traffic pattern, if the airport has not got any STARs or radar controlled arrival, so you would input ABC320/10, ABC330/10 etc. round to the runway extension, which you can get by going to the ARR page & choosing your landing runway & inputting the extension distance (there is a limit on it of 20nm i think).

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Pilots,Thanks for answers at this moment. However I'm a little persistent because I have the feeling (no pilot or FMC guru) that IRL this must be possible.Don't get me wrong: I'm fine without this feature but I'm very curious whether this function is possible. I included a little drawing (not to scale) to visualize what I'm talking about. The red coloured dashed lines are the ones!Replies are most welcome!Regards,Michel

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if you can work ou the radial & distance that you turn to base is at then of course its easy. if you have FSNav try using that (put ABC into the plan & then put a fix in).you will not be able to use ABC01 to make a radial fix from...

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Hi Michel, in my opinion your intention cannot be handled by the FMC in real life - and hence not in the simulator. The basic problem is that the FMC is not designed to solve your problem. You are trying to solve a simple problem which serves as a tactical goal, that is, one-at-a-time and short-term. It can be easily resolved by using the MCP because you only want to fly a heading of 200

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Hi All,What is under discussion here are what {for ease of use} we might call relative waypoints. The correct name for them is in the subject line. These waypoints can be created in the real aircraft as well.Say I want to create an LNAV path around a left hand circuit for a YBBN Rwy 01 visual approach and I am inbound from MC VOR which is about 40 miles to the the north and is the last waypoint before BN in my current Route of Flight. The aim is to create a series of sequential waypoints to give us a guide around the circuit.. Remember that a circuit is a VISUAL procedure and you should be looking out the window more than relying on the FMC/LNAV.I will have already selected YBBN RWY01 with a 5 mile extension from the DEP/ARR and now use the BN VOR as a starting reference point for building our LNAV path as it is located right beside Runway 01 and is avaliable from the Permanent Navigation Database of the FMC (This is what we see when we look at the AIRAC Date in the INIT page). So to start I create a waypoint about where I would break off from the inbound track MC-BN. In the LEGS page I would Line Select BN into the scratchpad and then type /-5 after it and then Line Select it back on top of BN in LEGS. This creates a waypoint called BN01 which is 5 miles short of the BN VOR and where I would start a turn to enter downwind and then onto where I would turn base, final and at last to the runway.In both the sim and real worlds I would now create a downwind entry point and so enter BN270/5 in the legs page after BN01, it would then appear there as BN02 (Note it will ask you to confirm the VOR Frequency from a list if there is more than one BN in the Permanent Database). So far this procedure works OK in the sim but IRL what we have done is create a waypoint in the Supplementary Database and so could then go on to create another point relative to BN02 of say BN02180/8 which would take me 8 miles south of BN02 flying about 5 miles west of, and parallel to, the runway {flying a downwind leg} and this second point would be called BN03. We can then create further relative waypoints to these if we wish or just join it up to the Runway Extension we created earlier.In the sim it appears that we do not actually have a Supplementary Database and so when we try and create BN02180/8 {BN03} we get the message NOT IN DATABASE.So the difference to the real aeroplane is that the PBD or PB/PB waypoints are created in the Supplemntary Database when the crew makes a manual entry. This is a temporary database that is erased automatically after landing.In the sim to get around this I would make the following entries in the legs page by creating PBD waypoints from BN VOR and taking a rough stab at where they would be from it. Not a perfect solution but it will work:BN/-5thenBN270/5thenBN200/8thenRX01Remember to always check your changes using PLAN mode on your ND and STEPing through your proposed changes to the LEGS page BEFORE you EXEC.Guys and Gals, we are getting pretty deep into this and I hope I haven't confused anyone..perhaps it is time for an advanced FMC tutorial on the net.. Any Takers just give me a wave :-wave :DRgds and I am still amazed at how good you folks ar at this!

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Geez Brad. Keep the tutorials coming.I know I'll be collecting them.Goran

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Hi BradThanks for your excellent contribution to this subject. And no, it's not confusing at all. Great "tutorial" in using PBD's and PB/PB. Neat feature really as we can define points anywhere in space for navigation...Actually I've used this feature quite some times. It just takes a bit of trial and error to get a good result as long as we don't have the possibility to create wp's relative to user created wp's(other than in sid/star creation as mentioned).As stated above, it's much easier to do this if you have FsNav running in the background. And the approach:http://forums.avsim.net/user_files/85992.jpgNot a great issue at all though, but is this possible in a future FMC upgrade, a Supplementary Database and the possibilty to create wp's relative to user created wp's? Anthony, someone?

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Hi Brad,Good to "see" you poppin' in here. No confusion at all, it all makes pretty well sens!Like I wrote in a previous posting, "logics" tells me that it must be possible to create a waypoint relative to BN02 (in your example). That the sim does not simulate is, means no problem at all. We work around is. Regarding the FMC manual: in you can spare time I would say: yes please.Many thanks again!Regards,Michel

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