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Unable to line-up using APP on autopilot

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  • Unable to line-up using APP on autopilot

    Say for EG im landing at northolt and have the NAV 1 tuned in correctly to 108.55 and the course set to 253 as per the map, why does the autopilot seem to want to fly the approach all wrong and is either way to the left or right when it lines it up.

    Seems i'm unable to do a proper autoland!

    I am more than able to line up the plane myself but wanted a bit of realism where the modern pilots (as far as im aware in my own perception) tend to favour at least 90% of approaches to be done by the autopilot. (especially with how the weather's been!)

    I can only think that to achieve a autoplot assisted landing is to tune in the ILS as normal and use my own imputs to track it, or use the autopilot to keep a steady & stable descent rate whilst I get the thing lined up and then use the HDG to keep it on track.....

  • #2
    Originally posted by gazpodel View Post
    Say for EG im landing at northolt and have the NAV 1 tuned in correctly to 108.55 and the course set to 253 as per the map, why does the autopilot seem to want to fly the approach all wrong and is either way to the left or right when it lines it up.

    Seems i'm unable to do a proper autoland!

    I am more than able to line up the plane myself but wanted a bit of realism where the modern pilots (as far as im aware in my own perception) tend to favour at least 90% of approaches to be done by the autopilot. (especially with how the weather's been!)

    I can only think that to achieve a autoplot assisted landing is to tune in the ILS as normal and use my own imputs to track it, or use the autopilot to keep a steady & stable descent rate whilst I get the thing lined up and then use the HDG to keep it on track.....
    Seems you have prepared the AP so far so right, but you need to activate the APP mode on the autopilot panel. Depends on the type of aircraft it might be called differently. If you are on an intercept heading towards the final approach course and the approach mode is armed, then it should take over the localizer and glideslope.
    In real life I hardly ever do autolands. I did about 10 during my 6 years of flying, all other landings were done manually.
    Good luck.

    wilco737

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    • #3
      Try as follows (standard FS9 autopilots, anwhere from the C-172 to the B-747).

      Tune the ILS in the NAV1. Don't care about the course, but if you select the course aligned with the ILS (runway) heading, then it will look nicely lined up in the instrument during the approach.

      Use the heading, altitude and vertical speed fuctions to establish yourself in a path that will intercept the localizer with an angle of 30 deg and at about 10 miles from the airport and at 2000 or 2500ft above the runway elevation.

      While flying in HDG and ALT modes, select the NAV mode. The NAV mode light will turn on but the HDG light will remain on. The airplane will keep flying the selected heading until the localizer becomes alive. Then the HDG mode will turn off itself and AP will start to capture and track the localizer.

      With this altitude and distance, you'll itercept the glide slope from below. When the glide slope becomes alive select the APP mode. The NAV mode will turn off but the ALT mode will remain on. The plae will keep tracking the localizer and the selected altitude. When the plane crosses the glide slope the ALT mode will turn itself off and the AP will start tracking the glide slope.

      --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
      --- Defend what you say with arguments, not by imposing your credentials ---

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      • #4
        I had the same problem with the Isle of Man approach but when i opened the airport in AFX the ILS was wrong i was set at an angle so i set it to the right degrees and all is fine now

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        • #5
          after looking at wilco's advice, I managed to pilot my POSKY 767 dreamliner paint from EGNM to EGSS without any trouble at all! I used the IFR flight plan and followed atc all the way as they vectored me in on the ILS approach. I selected APP mode as per wilco's advice and using that my plane eventially lined up itself with the centerline..I was happy with the approach and as it was light wind's I disabled both the APP and NAV and completed my approach with hands-on HDG adjusting the ALT mode on the autopilot as I went, after nailing a beautiful practice landing in seattle just a couple of sessions before, using the control which comes from ALT.

          I've not been anywhere near my laptop rest of the week due to a busy social calendar but should be free tonight to have some fun and a mess-around and will try experimenting with the new advice added. Looks pretty much like i've cracked it though!

          Thanks guys!

          Comment


          • #6
            Originally posted by WILCO737 View Post
            [...]
            In real life I hardly ever do autolands. I did about 10 during my 6 years of flying, all other landings were done manually.
            Good luck.

            wilco737
            Yes. See my AF-B742 landing at Dorval one thread below this... I don't trust autoland either. Seems a bit "hairy" but everything is in my hands and I know perfectly when to go around. I doubt if the onboard computers do know that.
            That's what airlines are good for, amongst others,
            The Gold Member in the 747 club, 50 years since the first LH 747.
            And constantly advanced, 744 and 748 /w upper and lower EICAS.
            Aviation enthusiast, since more than 35 years with home airport EDDL.

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            • #7
              Originally posted by LH-B744 View Post
              Yes. See my AF-B742 landing at Dorval one thread below this... I don't trust autoland either. Seems a bit "hairy" but everything is in my hands and I know perfectly when to go around. I doubt if the onboard computers do know that.
              the airplane does fine autolands. I am just not a big fan of it flying with 170 knots in 200m visibility and touchdown without seeing the runway. Weird feeling. Trusting the computer 100%...

              wilco737

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              • #8
                Originally posted by WILCO737 View Post
                the airplane does fine autolands. I am just not a big fan of it flying with 170 knots in 200m visibility and touchdown without seeing the runway. Weird feeling. Trusting the computer 100%...

                wilco737
                kias170 was not my speed in that Dorval final... I mostly use the B742 with full flaps and definitely less than 170. If I'd have been faster, that wouldn't have resulted in such a "hairy" turn *g*.
                I once did a testflight EDDL - LIPQ and the visibility was indeed worse than in Dorval. Your descent just happened within a "white wall". But you reach an alt when you have to decide...
                You are the professional (I am not), maybe you can help me with that: All waypoints down to alt 1000 are proved to be correct, but you still see nuttin.
                What do you do, still trust in the computer? And what happens if you "meet" an a320 who waits for his t/o in the mist of the staggered threshold... I don't trust in computers... Pilot's eyes have to be good enough to fly through an alt that is not more than your visibility.
                If that is not possible, I'll try to divert from Trieste.
                That's what airlines are good for, amongst others,
                The Gold Member in the 747 club, 50 years since the first LH 747.
                And constantly advanced, 744 and 748 /w upper and lower EICAS.
                Aviation enthusiast, since more than 35 years with home airport EDDL.

                Comment


                • #9
                  Originally posted by LH-B744 View Post
                  You are the professional (I am not), maybe you can help me with that: All waypoints down to alt 1000 are proved to be correct, but you still see nuttin.
                  What do you do, still trust in the computer? And what happens if you "meet" an a320 who waits for his t/o in the mist of the staggered threshold... I don't trust in computers... Pilot's eyes have to be good enough to fly through an alt that is not more than your visibility.
                  If that is not possible, I'll try to divert from Trieste.
                  In real life you use 2 (or 3) autopilots and they double check each other. They autopilots track the ILS (LOC and GS) all the way to about 50 feet. Then the "flare" and if applicable the "rollout" mode engage. And of course the autothrust retards the throttles to idle (reverse thrust will not be engaged automatically).
                  But you trust the computer and the autopilots all the way to the ground. You have decision heigts or alert hights (all depending on aircraft type) on which you decide if the airplane seems to do the right thing. If there are any doubts: GO AROUND! Be on the safe side. In the simulator many different failures are trained that you are alerted.
                  I haven't done many autolands in my life, but all went well. Nothing to complain about. But I am still no fan of it

                  wilco737

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