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Md11 Fmc - How To Force The 11 Overflying A Waypoint ?

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Captains,This might be a silly question, but how can I add this famous delta or triangle sign to a waypoint to force the MD11 to overfly a waypoint before starting the turn ?I was unable to locate this in the FMS manual.On certain STARS, the 11 is taking a shortcut and starting the turn a few NMs before the actual waypoint it is supposed to overfly, I wan to prevent that.Thanks and merry XMAS to all of youJoerg

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If the procedure requires that the fix be overflown, it should be written that way. There is no way to program a fix as a overfly fix in the FMS. The overfly feature in the MD11 should be working, it was tested. Just wondering, what is the specific case that you are referring to?

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The overfly feature does work if programmed directly in the procedure. My question is how I could add this manually to a fix (if possible at all)The specific case is the ILS RWY 34 approach into LSZH where I would like the UTIXO fix to be overflown as the 11 tends to take a 3-4 NM shortcut there sometimes resulting in a G/S overshot.ThanksJoerg

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Hello JoergI suppose what you are referring to is what happens when waypoints are entered manually. The FMS will compute the route as fly-by and not over-fly. I don't think it's possible to create the latter.The way around this is to fly those critical legs (to prevent overshooting a G/S for example) in HDG mode. What I do in my 737 is I start turning about 1,5 - 1 NM before the wayoint depending on my ground speed. It works fine. Note that you would be in HDG mode on that stage of the flight anyway, given final vectors by ATC.I know this isn't realistic but it's the best way. Alternatively you could place custom waypoints but that could be less accurate and it's definitely less realistic.Best regards

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The overfly feature does work if programmed directly in the procedure. My question is how I could add this manually to a fix (if possible at all)The specific case is the ILS RWY 34 approach into LSZH where I would like the UTIXO fix to be overflown as the 11 tends to take a 3-4 NM shortcut there sometimes resulting in a G/S overshot.ThanksJoerg
I am looking at the chart. UTIXO is on the final approach course, so I am trying to picture where you are coming from and how to suggest a solution. First of all, manually programming overfly in the FMS is not possible. Secondly, I don't think an overfly is what you want to do in this case anyway because by definition an overfly means the aircraft holds the same track that it had approaching the fix while it is over the fix and does not make a turn until past the fix. Since UTIXO is on final approach course and I assume you are on and intercept course, then flyover would take you past the final course.Assuming your track on the way to UTIXO is an intercept track (and not the teardrop pattern shown on the chart), then use HDG to hold the intercept track with APPR selected and the A/P will intercept the LOC/GS as long as you are close enough.If you are trying to fly the teardrop pattern where the sebments are from KLO to ZH726 thence a right turn direct UTIXO, then it is fix ZH726 you want to flyover; although in this case I think the procedure should be manually flow or using HDG since it is not a GPS or RNP approach. Ideally, the FMS procedure would have the arc between ZH726 and UTIXO defined (an AF leg using ARINC424 terminology).So, if this doesn't answer your question, be a little more specific and I'm pretty sure I can help.

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DanThanks, yes it is the teardrop out of BLM1G STAR via KLO and ZH726 to UTIXO that I'm refering to.I used to fly this "manually" via HDG approach - all fine there - but tried full NAV approach a few days ago when the 11 started a heavy right bank a few NM's before UTIXO resulting in a missed G/S capture because the plane cut off a few NM'sin the descend profile.Anyhow, nevermind, I was just curious if forced overfly can be added to any waypoint/fix in the FMS like f.e. in the 767.I will continue to use HDG mode.ThanksJoerg

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Well, here is what I would try: While enroute to ZH726, put in HLD then quickly DIR TO UTIXO and put her back in NAV A/P. The desired result is she will turn to UTIXO, meanwhile APPR is armed as LOC comes alive and down you go. This will substitute for the FIX OVERFLY ZH726 TURN RIGHT DIRECT FIX UTIXO that can be put in the sidstar file if you want to try playing with that too.

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Assume you want to overfly a fix called FOO. The simplest trick is enter FOO/-0.1 in the scratchpad and upload on top of FOO. This will create an "along route waypoint" 0.1 miles BEFORE FOO. Due to the rules of waypoint sequencing in any LNAV (NAV here) unit, FOO will become an overfly waypoint. I.e. this kills turn anticipation associated with FOO. Helpful ?Vangelis

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Vangelis, DanThanks muchVery nice workarounds - much appreciated. You guys are greatJust one question left - when I enter "FIX NAME"/-0.1 into the scratchpad and try to upload into the FP, I get a "Not allowed" message.Entering a fix without -0.1 works fine.ThanksJoerg

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Assume you want to overfly a fix called FOO. The simplest trick is enter FOO/-0.1 in the scratchpad and upload on top of FOO. This will create an "along route waypoint" 0.1 miles BEFORE FOO. Due to the rules of waypoint sequencing in any LNAV (NAV here) unit, FOO will become an overfly waypoint. I.e. this kills turn anticipation associated with FOO. Helpful ?Vangelis
No, because a Place Distance point cannot be created closer than 1 NM from the original waypoint and 5NM from aircraft position. So the closest you can get is 1 NM from the intersection.Best regards,Floris

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Yes ! 1.0 instead 0.1 does it.It worked - just landed in LSZH and with the fix applied she was turning beautifully in the descend profile to capture LOC and G/S right on time.Excellent !Thanks much gentlemen for the advice and help and merry XMAS to all of youJoerg

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