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Posted

Got a new attitude indicator and it's doing strange things. Vacuum pump is new, filters are new. Set it prior to take off and by the time I reach 1300 feet while still climbing it shows level flight. Swapped it out with another one and it does the same thing. Had the suction gauge checked and it was a hair low so we increased it. Still does the same thing. Any ideas?

Posted

What do you mean by "I set it"?    Also, are you saying the pitch shows 0 degrees when it should indicate 5 to 10 nose up?    If at that point you level off, does it then indicate nose down?

Posted

I guess what I mean when I set it was we used a proper calibrated pressure gauge then adjusted the regulator to the higher end of the green arc. It shows about 3-5 degrees pitch up when climbing until I reach about 1200 feet then it shows level in the climb. When I level off it shows about 3 degrees pitch down . Did not check for vacuum leaks yet. Thought for sure it was a pressure issue. Once level if I adjust the AI it seems to be proper.

Posted (edited)

What is the angle of your panel in level fligh, not sitting on the ground? The AI angle needs to match your panel. You can see what the  standard values are by looking at the spruce web page.   Some manufactures will do custom angles also.

Edited by N601RX
Posted

It's 4 am and my math be off. If you have an 8° unit in your J and you level it out on the ground, you would be starting off 8° nose down (a Mooney sits a few degrees nose up on the ground). Assuming a "normal" climb, I would expect some where around 10° to 12° in pitch. This could explain your 3° to 5° in climb. You level off, since the pitch on the ground is a few degrees of nose up when you leveled it, so I would expect the unit to be a few degrees nose down. I get that right? I'm tired...

Sent from my iPad using Tapatalk

  • Like 1
Posted

So I got one of those leveling apps. Sitting on the ground the panel is roughly 3-4 degrees.

So I set it to 4 degrees prior to take off and it works as advertised. Go figure!

Posted

Inflight level is considerably different than sitting on the ground.  To level the plane on the ground you will have to jack the mains up until the tail is close to head high.  The procedure is in the maintaince manual.

Posted

A J sits about 3 degrees ANU on the ground.  I always see people setting the attitude gyro for level on the ground, then readjusting it after level off. Just set it to +3 and leave it. 

  • Like 2
Posted

It sounds like it is erecting to fast. Did you set the vacuum?

I used to fly a couple of bizjets that had a "Fast Erect" button on the panel. I was always too afraid to push it to see what would happen. :P

  • Like 1
  • 3 weeks later...
Posted
On 10/25/2015, 5:19:40, jetdriven said:

A J sits about 3 degrees ANU on the ground.  I always see people setting the attitude gyro for level on the ground, then readjusting it after level off. Just set it to +3 and leave it. 

that's what I do.  I leave my AI showing ~5 degrees on the ground, so it is usually at 0 during flight.  

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