Simviation Forum - Autopilot Route Tracking Problems

Jul 10^th, 2003 at 7:43pm

Iroquois Offline
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Ontario Canada

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I was having some problems with the autopilot when setting the instraments to track a GPS or VOR route. It seems to mostly occure when I'm in prop aircraft. I'll program a route and set up the autopilot to follow it. The plane will sometimes follow the route for a bit then turn way off course or will turn way off course to begin with. I have set up the autopilot properly and this seems to occure in all weather conditions from no wind at all to storm. I was wondering if this was either a torque problem or if it's a glitch. I don't think its a physical problem though because the plane handles fine manually.

(When it comes to VORs, I'm aware of aligning the OBS and have done it many times with other planes that follow radials fine)

I only pretend to know what I'm talking about. Heck, that's what lawyers, car mechanics, and IT professionals do everyday. Wink

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Reply #1 - Jul 10^th, 2003 at 9:29pm

jaythree Offline
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just lookin out ta winda

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The first thing I would look at is what aircraft it happens in. all props or just some? is it the same aircraft all the time or do the work sometimes and sometimes not?
the reason I am headed this way is that if it is an add-on aircraft it may be a problem with the panel or the air file for that aircraft. my second thougth was are you sure you are in range of the vor? sometimes at extreme ranges they will cut in and out and loss of signal for a few moments might make it impossible for your autopilot to recover the track when the signal is restored.
the signal is affected by distance from the station, the aircraft's altitude, terrain between you and the station, and weather.

thou shalt maintain thy airspeed lest the ground come up and smite thee

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Reply #2 - Jul 10^th, 2003 at 9:46pm

Iroquois Offline
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Happy Halloween
Ontario Canada

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Well, all props just about. It happens on the C172, DC3, Boeing 377 Stratocruiser, etc. The C182 is perticularly bad for this. Like I said, its not just VORs, they won't follow GPS tracks as well. Funny thing is, I don't have this problem with jet aircraft.

I only pretend to know what I'm talking about. Heck, that's what lawyers, car mechanics, and IT professionals do everyday. Wink

&&The Rig: &&AMD Athlon XP2000+ Palomino, ECS K7S5A 3.1, 1GB PC2700 DDR, Geforce FX5200 128mb, SB Live Platinum, 16xDVD, 16x10x40x CDRW, 40/60gb 7200rpm HDD, 325w Power, Windows XP Home SP1, Directx 9.0c with 66.81 Beta gfx drivers

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Reply #3 - Jul 13^th, 2003 at 12:02pm

nickle Offline
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The autopilot deficiency is due to MS and not you or your computer. Much has been discussed in forums on this subject. MS provides a BS explanation that the AP is more "realistic". My description is that AP perfromance is unacceptable.

Another MS 2002 deficiency, and more important to me, is that the elevation (horizontal) "fly to" in the Flight Director has little relationship to the ILS horizontal glideslope bug in the jets.

Really dumb stuff.

Maybe a fix in Centennial?

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Reply #4 - Jul 14^th, 2003 at 2:48am

packercolinl Offline
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I seem to find on the smaller ore older planes you actually need to set up your heading and altitude manually and then engage AP. Which is fair enough when you consider you are not going to get the navigation system available for a 747 in a Cessna 172.
The price of the 172 alone wouldn't cover the cost of the nav system.

White on White fly all night.&&&&Red on White you're alright.&&&&Red on Red you'll soon be dead.

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Reply #5 - Jul 14^th, 2003 at 12:28pm

fisharno Offline
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This happens in my C-5, too.

In an IFR flight, using GPS, set your heading on the AP to whatever heading ATC gives you for your outbound. You'll need to adjust your heading every so often, due to the magnetic variation, but for the most part the AP will keep you close to your filed track. If you use, (and keep up with) your VOR and NDB navaids, and plot the frequency changes correctly and accordingly, you'll stay right on track.

Actually, this good practice using your nav radios, and planning ahead during your flight.

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Reply #6 - Jul 14^th, 2003 at 5:03pm

nickle Offline
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I love YaBB 1G - SP1!
San Diego, Ca

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Good suggestion on the A/P Nav problem. Heading hold is the best solution.

But thats work.

You really don't think the guys/gals in the front are working do you?

Hint: The A/P, AT, APP combination will fly the aircraft better than almost all pilots given system maintenance.

In the not too distant future, the stew will ask you, a passenger, if you have MSFS experience. If so, you will be invited to monitor the auto equipment in place of the pilots.

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Reply #7 - Jul 15^th, 2003 at 6:39am

packercolinl Offline
Colonel
Any more laid back I'd
be asleep!

Posts: 1049

Like a lot of things that 'work' can be fun and when the plan comes together very satisfying!

White on White fly all night.&&&&Red on White you're alright.&&&&Red on Red you'll soon be dead.

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