Brittain Autopilot Operation

[Ashy]

I hope you don't mind, I am a fellow aviator but not a Mooney driver. I have dropped by to see if anyone could answer a couple of my questions regarding the operation of the brittain Autopilot.

We have a 1965 Beech Debonair, we recently fitted a Brittain BSS wing leveler with Accuflite and Accutrak 11 addons. Brittain describe it as follows:

A basic wing leveler in conjuction with both the Accutrak and Accuflite add-on systems. This would give you basic wing leveling with the ability to trim out aysemtrical aircraft loading, etc, navigational tracking of two nav sources, including panel mounted GPS and commanded heading including intercept capabilities via a directional gyro with heading bug.

Brittain state the following operating procedure for tracking from the VOR/GPS:

1. Engage autopilot master valve
2. Trim for level flight
3. Select desired OBS or GPS course
4. Set heading bug to agree with desired course
5. Engage Accuflite (heading switch) and Accutrak (On-HI) to desired Nav1/Nav2

Aircraft should turn to intercept L-R needle up to 45° - cross wind adjustment may be needed on heading bug to keep nav needle centered if more than 10° required

We have the Accutrak 11 coupled to a King KLN90B GPS together with the heading bug system. I have operated the system as Brittain has said. I would love to hear how other pilots operate this system, I am not sure I have all the technique down pat at this time.

[takair]

I have this system in my 64E model.  It operates like described above.  The hardest thing to get used to is using the heading bug to wash out cross wind correction.  Basically, allow the autopilot to settle out for a couple of minutes after established on course.  If your CDI remains uncentered, turn the heading bug a few degrees in the direction of the needle and allow to stabilize. You are basically bracketting the course using the heading bug.  If the gains are set up correctly it will do a fine job of tracking.  If it does not work as advertised then your gains may not be set up right.  This may be the most difficult part of initial set up.  Brittain has excellent tech support if you have any problems. 

[GeorgePerry]

Quote: Ashy

We have the Accutrak 11 coupled to a King KLN90B GPS together with the heading bug system. I have operated the system as Brittain has said. I would love to hear how other pilots operate this system, I am not sure I have all the technique down pat at this time.

[carusoam]

Ashy,

To add to the discussion...

I also have the KLN90B.  It is an excellent source for straight flight navigation.  I have it connected to a different autopilot (KAP150) that automatically corrects for X-wind component.

[1] I am used to seeing 5 - 10 degrees of "crab" to stay on course.  Sometimes much larger.

[2] Comparing portable GPS track and to flightaware.com the lines are perfectly straight.

[3] I use the desired track vs. actual track to "fine" adjust the HSI.

[4] Always check the HSI against the compass.  Any large disagreement can lead to wandering.

[5] GPS accuracy as a nav source is incredibly straight compared to scalloped course following of VOR source.

[6] When flying IFR, consider using turn anticipation on the KLN90B.  This really helps keep to the centerline during course changes.

On another subject...How do you update your KLN90B data base?  Cartridge, PC upload or other....

Best regards,

-a-

[Ashy]

I have a data port in the panel and update via a note book computer. The USB/Dataport cables are available from King I believe. It seems a simple method.

[Ashy]

Thanks for your help on the Brittain AP, I will play around a bit more.

[scottfromiowa]

George,

Could you elaborate a little more on the "heading bug"?  I have an AccuTrak with a Garmin 300XL and I am interested in what hardware you use that I could benefit from to improve the tracking in GPS...

Thanks,

Scott

[GeorgePerry]

Not sure what else to say really...The heading bug on the DG is tied into the brittain AP system.  I turn on the heading hold switch and spin the bug to the heading I want the plane to hold.  Works like a champ.

[N601RX]

It is marketed as Accu Flite by Brittain.  It will track the DG output.

[Hank]

I have the Accu Flite and Accu Trak both, but fly most of the time with the heading bug. Reading the above, do I need to use the 'bug when using the auto pilot also? I thought it was either/or.

"Heading bug off; AP on; Sensitivity Low; NAV 1" is not the correct setup???

I can never remember which name goes with which--one is just the heading bug, one is the autopilot. Apparently the bug is Accu Flite, and the one that will fly the approach if I want it to [the "auto pilot"] is Accu Trak?

And when is the proper time to select "High Sensitivity"??

[danb35]

They are both autopilots; they just serve different functions.  The AccuFlite follows a given heading, while the AccuTrak follows the CDI.  I select high sensitivity on mine most of the time, but I track a GPS, not a VOR.

[Ashy]

Dan

Do you use the heading bug input to counter crosswind also when you are tracking the GPS with the Accutrak?

[danb35]

When tracking the GPS, I usually leave the AccuFlite turned off.  I haven't found a need to take any particular steps to counter crosswinds so far--AccuTrak on with the needle centered, and it will stay centered.

[takair]

Quote: Ashy

Do you use the heading bug input to counter crosswind also when you are tracking the GPS with the Accutrak?

[Hank]

Well, the next time I'm out, I'll try running both and set to 'Hi.' Maybe we can achieve a consensus on G-430 operation: with or without the heading bug for crosswind drift.