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autopilot question

PostPosted: Sun Apr 10, 2005 10:14 pm
by JackieAdkins
what are the Backcourse and Yaw Damp. thing for on the auto pilot? i have everything else on the AP down except the BC and Y/D. thanks

Re: autopilot question

PostPosted: Mon Apr 11, 2005 3:56 pm
by WebbPA
I'll tell you everything I know about backcourse hold.  Keep in mind that I have used this feature exactly once, and that was just to see if it worked.

Backcourse hold is the opposite of approach hold.  If you have an airport with runways at 9 and 27 and only runway 9 has an ILS you can use the backcourse hold and the ILS to land on runway 27.

Re: autopilot question

PostPosted: Mon Apr 11, 2005 4:05 pm
by jrpilot
So thats what it is..Do you know how accurate it is?

Re: autopilot question

PostPosted: Mon Apr 11, 2005 4:41 pm
by JackieAdkins
sorry i just dont understand that one, anybody else?

Re: autopilot question

PostPosted: Mon Apr 11, 2005 5:21 pm
by Nexus
The Yaw damper is basically a gyro operated SAAS (stability augmentation autocontrol system)...yes yes very nifty name, but what does it actually do?
Well, the yaw damper provides immediate rudder input when necessary, to aid in cancelling out yaw tendencies, such as dutch rolls. Its an autopilot for the rudder that nullifies the yaw so you can keep your feet on the floor  

Backcourse is  A "reversed" ILS approach (you're approaching the runway from the opposite direction). Though the glideslope won't work, you still have LOC information. There have been a few discussions about Backcourse lately, I suggest you do a search, and the APR (APPROACH HOLD) has been brought up quite a few times aswell, so look that up while you're at it.
I know some posters had WONDERFUL replies which gives you all the information you need.    :)

Re: autopilot question

PostPosted: Mon Apr 11, 2005 9:15 pm
by beefhole
Here's something I wrote a while ago-I forgot to mention that you wouldn't have any glideslope, so just keep that in mind.

Okay, assume you have one runway at an airport. Runway 36/18.  36 has an ILS, but you want to make an ILS landing 18.  Tune 36's ILS, and then think of the localiser like a mirror.  Instead of chasing the dot, the dot now represents YOUR position on the localiser, as opposed to where you're supposed to fly.  When you hit Backcourse, it does the same thing as hitting APP except it will follow the new set of rules (dont chase the dot, because the dot represents your position on the glideslope)

Here, go to an airport that has a runway with only one ILS, and land the other way.  Fly it just like an ILS approach, except hit B/C instead of APP, and you need to manually control altitude.

Did that do it?

Re: autopilot question

PostPosted: Tue Apr 12, 2005 1:49 am
by OTTOL
[quote]

Re: autopilot question

PostPosted: Tue Apr 12, 2005 7:51 am
by beefhole
Yeah... I knew that... :D

The thing that I've found is, that in FS, the course thing makes absolutely no difference at all.

Re: autopilot question

PostPosted: Tue Apr 12, 2005 4:18 pm
by JackieAdkins
awesome thanks for the BC info, and with the Y/D would you use that when there is alot of wind involved or what? when would be a good time to use that?

Re: autopilot question

PostPosted: Tue Apr 12, 2005 4:21 pm
by beefhole
It should be engaged whenever autopilot is engaged-on during the takeoff roll, off during the rollout.