Autopilot Problems

[checkride]

Hey Guys

 

need some help quick for a friend. He is flying a jabiru J430 with a Digiflight II VS autopilot, but when we engage the autopilot

 

to hold heading and alt the aircraft wanders around, it doesn't lock on the the heading or alt and hold it there does the same with gps

 

steer.

 

Any ideas what could cause it.

 

 

[Tracktop]

My trike has the same problem

 

:hittinghead::hittinghead:

 

 

[Guest Andys@coffs]

Tracktop....I suggest you replace your autopilot with a female version, preferably half your age.... It may still wander but it will be less annoying to you.

 

Checkride, my AP in my J230 is a different brand but to a certain extent that is irrelevant. If by fails to track do you mean that if a heading of 270 is called for it varies between 267 and 273, oscillating around 270. If that is the case then to a certain extent that is a characteristic of these AP's and usually there is a gain and a damper setiing that is user (or in GA world LAME) adjustable that can damp down the amount of oscillation and the extent of the swing either side.

 

Understand however that in getting rid of that you then make the device less reactive to movements in the air and some strong buffeting that lifts a wing may be much more slowly reacted to....Like most things in life its a compromise.

 

If you dont mean that at all, and rather the servo isnt being engaged at all when AP elected on then I suggest that you read the self test features of the AP as I believe that most self test the electronics of the servo, but dont of course test the mechanical aspects. If Self test passes but the servo still doesnt engage (should probably be a loud click from the servo as the clutch engages) then I suggest it needs to go to someone who can fix them or the OEM.

 

Andy

 

 

[facthunter]

Better choice.

 

With the type femme autopilot get the close to 100% age version. They don't wander as much. If there are any malfunctions, don't try to work out why.

 

Checkride, it almost seems as if it is not turned on. This can be a problem with the "femme" type as well...Nev

 

 

[Guest Howard Hughes]

Checkride, it almost seems as if it is not turned on. This can be a problem with the "femme" type as well...Nev

:thumb_up:

 

[HEON]

I have one of these and do not have this problem.

 

I assume you have tried all the adjustments in the instructions?

 

If so, I would look at mountings of servo's and if different/adnormal resistances in attachments to and actervation of control rods/cables over their full range of movement.

 

If all OK there I would be talking to who installed and/ or Australian dealer.

 

 

[checkride]

Servo engages when AP is on everything works but it just oscillates around the heading

 

you select on the AP and oscillates on the gps track as well.

 

I will try and calibrate it again and see if it is any better.

 

 

[facthunter]

AP

 

Can you adjust the sensitivity? What is the heading reference source? Nev

 

 

[Guest Andys@coffs]

so if the oscillation feels like an issue, then my question would be if you review GPS track against GPS plan how much off either side of the plan is the track? If you cant seperate it then "feels" does not equal "is" a problem. I remeber spending 8hrs in the back of an RAAF hercules C130 when it was doing the same thing on AP so its not just a small plane issue....

 

Andy

 

 

[Steve Donald]

hi i would be checking each electrical connection as well as looking for voltage drop at each point including engine on and off, this has been a problem with some, if you find a drop check the resistance on that wire first as it could be just faulty wire or a poor connector. Good luck hope you get it sorted