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Guest dpokluda

Sharp turns in flightplan

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I am having issue with RadarContact when flying airplane like A320 (Wilco/feelThere). I am having issues with sharp turns. For example when I create a flight plan with a SID on departure, SID might contains a couple of relatively sharp turns with very short legs (2-10 nm). It very often happens that Airbus will turn sooner so that it reaches the waypoint. The problem is that RadarContact will not see me reaching the waypoint and it will stay on the previous waypoint. I would then have to manually request direct fly to the next waypoint. Unfortunately before I get the approval the plane is already turning to the next waypoint on my SID. :-(What is the right think to do here?

  • Should I include SID on my flightplan (created using FSCommander) or should I just omit the SID and STAR in FSCommander and then later add it when programming FMC in Airbus?
  • Can I tweak RadarContact so that it reacts correctly when the airplane turns sooner when sharp turn in in the plan?

What is the right think to do?Thanks,David.

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If you want to fly over a waypoint you cand use Overfly function. You cand add overfly function to a waypoint using OVFY key from your FMC.

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Some Departure Procedures (DPs) are meant for aircraft with a lower groundspeed. These DPs will note the PANS-OPS category (A, B, C, D, or E) of the intended aircraft on the chart. The A320 is a category C aircraft, and hence, can't fly procedures meant for A or B category aircraft as it's groundspeed is too high. You need to lead the turn in order to adhere to the DP, or you'll end up overshooting the next waypoint on the list.

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Thank you all - I am assuming you are telling me not to put departure waypoints into FltPln that I use with Radar Contact if it has waypoints too close. How about the sharp turns in the middle? Is there a way to tell RadarContact to be more tolerant? Currently I actually have to be exactly above the waypoint for RadarContact to move to the next one?Do you have (somebody) similar problem when flying fast airliners? What do you with that?David.

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Do you have (somebody) similar problem when flying fast airliners? What do you with that?David.
Pick a different DP. If your groundspeed is too high, you simply cannot adhere to certain DPs that are meant for slower airplanes. I suggest that you download Navigraph nDAC and invest into some terminal charts. It's payware, but it's well worth the money to have the added situational awareness on your flight-plan. The more prepared on the ground you are, the less surprised you'll be in the air. :(

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I am having issue with RadarContact when flying airplane like A320 (Wilco/feelThere). I am having issues with sharp turns. For example when I create a flight plan with a SID on departure, SID might contains a couple of relatively sharp turns with very short legs (2-10 nm). It very often happens that Airbus will turn sooner so that it reaches the waypoint. The problem is that RadarContact will not see me reaching the waypoint and it will stay on the previous waypoint. I would then have to manually request direct fly to the next waypoint. Unfortunately before I get the approval the plane is already turning to the next waypoint on my SID. :-(What is the right think to do here?
  • Should I include SID on my flightplan (created using FSCommander) or should I just omit the SID and STAR in FSCommander and then later add it when programming FMC in Airbus?
  • Can I tweak RadarContact so that it reacts correctly when the airplane turns sooner when sharp turn in in the plan?

What is the right think to do?Thanks,David.

that means you aren't getting within 2miles of the sid checkpoints?if you know this is going to be problematic. you could choose to not include the sid in the .pln, and to use a flex dp option.jd

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I slow the aircraft at early sharp turn waypoints usually present because of terrain or adjacent airport traffic pattern conflicts. I do eliminate those within two miles of a runway on departure.In the Boeings I will use MCP heading to get closer but not on with a slight overshoot of the route track.FAA terminal charts are available for free from flightaware.com. Other charts from VATSIM chapters or referenced links are available for some FAA areas.

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I slow the aircraft at early sharp turn waypoints usually present because of terrain or adjacent airport traffic pattern conflicts. I do eliminate those within two miles of a runway on departure.In the Boeings I will use MCP heading to get closer but not on with a slight overshoot of the route track.FAA terminal charts are available for free from flightaware.com. Other charts from VATSIM chapters or referenced links are available for some FAA areas.
Yes, I actually used the real charts (from VATSIM) for KSEA airport. There were multiple waypoints very close together and Radar Contact (my airplane actually) wasn't able to hit them all with 2nm precision. I ended up flying on my own (autopilot driven by FMC) and then I was behind the DP I have requested RC directly to the next waypoint. I was just wondering if it is just me and how others go around this issue.Thanks,David.

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I looked at the DPs downloaded from here within the complete bundle:http://flightaware.com/resources/airport/KSEA/proceduresIt looks like the RNAV are the tightest turns. About all North and South departures have them.I would suspect that IAS is slow around V2 with possibly take-off flaps still engaged to allow the turns in such a tight area. I would also suspect that these might be hand-flown. The 90 degree turns only appear to exist when departing 16R/34L for western initial departures.The initial turns at two or three miles from the ends of the runways allow some altitude and airspeed gain before turns are required to prevent any altitude loss or stalls just after lifting off. Normally airliner turns are limited to fifteen degrees of roll for passenger comfort and set that way as minimum bank when on A/P - FMS but once enough speed is up thirty degrees might be used if necessary. Speed in the pattern might be limited to 210 knots anyway so completing the turns within the fly-by tolerance of two miles should not prove too difficult.

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It looks like the RNAV are the tightest turns. About all North and South departures have them.I would suspect that IAS is slow around V2 with possibly take-off flaps still engaged to allow the turns in such a tight area. I would also suspect that these might be hand-flown. The 90 degree turns only appear to exist when departing 16R/34L for western initial departures.
Negative. In order to adhere to certain noise abasement procedures, the aircraft needs to be clean ASAP. Flying around with all of that drag out will wake up everyone in the neighboorhood. This DP profile doesn't look that bad, and I'll give it a shot in the 744 when I get home and try to duplicate the OP's issue.
Normally airliner turns are limited to fifteen degrees of roll for passenger comfort and set that way as minimum bank when on A/P - FMS but once enough speed is up thirty degrees might be used if necessary. Speed in the pattern might be limited to 210 knots anyway so completing the turns within the fly-by tolerance of two miles should not prove too difficult.
Negative, again. The bank limit selector is usually left alone, except in a non-normal procedure like in a engine-out scenario. LNAV ignores the bank selector anyway. The only autopilot mode that follows it is heading select. When the bank limit selector is left in the AUTO mode, the aircraft's max allowable bank angle is limited by it's True Airspeed (TAS). The higher the TAS, the lower the allowable bank angle becomes. Likewise, the lower the TAS, the higher the max allowable bank angle becomes. It's done that way to prevent wing warp and overcorrections, as the outboard ailerons are also locked out at higher TAS. PANS-OPS specifies that the maximum allowable bank angle in holds at 230KIAS is either 25* or 3* of bank per second (for category C and D aircraft), whichever is less. I can't think of any situation where you would need more than 25* of bank to adhere to a turn in normal circumstances.Also, anything more than 25* will set off the GPWS "Bank Angle" aural warning.

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The 737NG docs I have indeed as you state do show the bank limit is effective only in AFDS HDG and VOR mode.At a clean configuration a climb speed of 210 knots is well above the stall speed of I think all but heavies at 25 degrees angle of bank.Regarding use of flaps in the 737 series I don't think the use of five degrees would cause that much drag to add to the noise level. Those 90 degree turns were about I think seven to ten miles out. The typical AGL to reduce pitch is about 1500 and the airspeed with reduced thrust still should be low enough to reduce the turn radius yet high enough to prevent turning stalls probably without any flaps.As far as RC goes I'd try a no altitude restriction departure which basically is your own navigation until transferred to center. Try a speed of 210 to 230 just to see if it still crosses those waypoints in the departure phase within the two mile waypoint fly-by restriction.

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Ok, let's me ask concretely (I am actually not expert in this area so I might do something wrong): I am flying A320 from KSEA to PANC.

Now should the plan contain all the waypoints including BANGR6 waypoints: DODVE WUREL ATOME BREMM BANGR? How about the the approach waypoints - should I add them to the flight plan right in FS Commander? Or should I just use this flight plan in FS Commander (and therefore RadarContact as well) BANGR ARRIE FOCHE PRYCE BKA LAIRE ROLNZ YESKA and then when I import the plan to FMC just specify the right SID and STAR? What is the recommended way? How do you (would you) do that? Thanks,David.

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To insure your waypoints are in sync with RC4 and the aircraft through the DP and STAR I would let FSC expand them and import the same plan into the FMC and RC.In this case since the first waypoint is within thirty miles RC will recognize this as a filed plan by waypoints at that first waypoint and expect you to navigate the DP on your own (by FMC, etc.,) hitting all of those waypoints and not issuing vectors. By not using the FMC SID/STAR database, which could be out of sync with your FSC SID/STAR database, you avoid discrepancies between the two. RC would still need the waypoints starting at about thirty five miles out anyway for you to use vectors if you wish. I'd leave out that waypoint about two miles from the departure end. In RC since the beginning of the DP is runway specific until about ten miles out you'd have to request the correct runway.The process for the STAR is similar. At PANC most of the STARS are not runway specific and give you vectors from a specific point. If you are willing not to use specific runway rnav then you could put the STAR waypoints into the plan and when approach assigns you the runway you could take vectors and just call up the ILS of the known runway for situational awareness and if AIRBUS does it tune the NAVs or manually tune them to the displayed frequency for the raw data. If you want to use RNAV for a full approach include those in your plan knowing which runway you'll use. After RC approach contacts you with the assigned runway ack it and then go to the extended menu to choose the runway and approach type you want for an IAP. RC will then let you navigate it on your own. If you use the FMC make sure the waypoints are the same that RC gets until your IAP takes effect.For the first thirty miles of your flight and last forty if you want altitude flexibility choose NOTAMS on the Controller Page for each airport so RC altitude commands become advisory in nature.

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