Artificial Horizon slow to wake up

[TheTurtle]

I think A&Ps have worse handwriting than doctors!!  These logs are like reading chinese.

[carqwik]

;My KI-256 (vintage late 1990s) exhibits "slow to erect" when it's starting to go bad...it only gets progressively worse over time.  Overhaul is in your near future for sure.  Once overhauled, you'll note that it erects in seconds after engine start...at least mine does.

[mooniac15u]

2 hours ago, TheTurtle said:

heres the AI.  you are right, some of the other planes I looked at had the white and black realllllly old school AIs.

Ill check the logbooks.

 

I was looking at your layout here and in the other picture you posted.  I notice that you have both CDIs on the far side of your radio stack but you have an open spot in the lower right of your primary panel.  If you are going to be working on your IR it might be worth having your primary CDI moved into your field of view.  It will make your instrument scans a lot easier.

[TheTurtle]

Just now, mooniac15u said:

I was looking at your layout here and in the other picture you posted.  I notice that you have both CDIs on the far side of your radio stack but you have an open spot in the lower right of your primary panel.  If you are going to be working on your IR it might be worth having your primary CDI moved into your field of view.  It will make your instrument scans a lot easier.

Im thinking of moving both of them actually.  The ADF is inop so that CDI can come out from the bottom left.  Plus I hate that gross grainy black panel which I want to replace as well.  1 step at a time!!

[bradp]

If you have a hdg on the DG that drives an autopilot you will have both wires and tubes going to the back of the instrument.

 -B

[takair]

A few things to look at before replacing the attitude indicator:  the vacuum gauge shows good, but you may not have enough air flow to/from the gyro.  This is as important or more important than the vacuum reading.  Causes I have seen for low flow include kinked hoses, tight turn radius hoses, broken hoses, plugged filter.  Also, sometimes the basic AN style plumbing fittings are too restrictive.  Unfortunately, the correct fittings are pricey.  Another thing to look for is loose fitting on the back of the gyro.  I have also seen the fittings over torqued, cracking the case housing and causing a leak.  

A friend recently reported a similar problem on his new to him aircraft.  Minor improvements in hose routing (slight collapse) and new filters seem to have cured this.  That said, a tired gyro can also cause this, as others have suggested.  Be careful when working with old hoses.  Flakes of rubber can FOD out a gyro or vacuum pump.  If the wiring behind the panel is a rats nest, be very suspicious of the hose routing.

[Guest]

4 hours ago, Mooneymite said:

They'll take longer and longer to erect until they don't.

 

Modern medicine can help with that, speak to your doctor.

Clarence

[peevee]

5 hours ago, Mooneymite said:

Reading the original post, it sounds like a classic case of a vacuum driven A.I. that's about ready for overhaul.  They'll take longer and longer to erect until they don't.

However, if the plane has been sitting a lot, sometimes frequent use can get 'em going again.

This is what ours did. Eventually it fell over in flight. 

Less than 1amu at Porter straight in Tulsa for overhaul. 

 

My understanding is vac pumps let go suddenly and don't degrade. Short of a broken or cracked line I'd say your ai is due for work. 

Edited August 25, 2016 by peevee

[Cruiser]

The gyros in the AI are not spinning up to full speed due to wear/friction in the bearings/guides.

Sometimes movement (turns during taxi/vibrations/bouncing) will help relieve the excess pressures. Once the gyros are spinning at the proper speed the gyro will work properly.

There are guidelines for the max. time it takes to erect. If you are flying IMC, I would have a backup or brush up on your partial panel skills.

[peevee]

1 hour ago, Cruiser said:

The gyros in the AI are not spinning up to full speed due to wear/friction in the bearings/guides.

Sometimes movement (turns during taxi/vibrations/bouncing) will help relieve the excess pressures. Once the gyros are spinning at the proper speed the gyro will work properly.

There are guidelines for the max. time it takes to erect. If you are flying IMC, I would have a backup or brush up on your partial panel skills.

What I read when I looked into it indicated the erector mechanism was usually the first to go

[TheTurtle]

5 hours ago, takair said:

A few things to look at before replacing the attitude indicator:  the vacuum gauge shows good, but you may not have enough air flow to/from the gyro.  This is as important or more important than the vacuum reading.  Causes I have seen for low flow include kinked hoses, tight turn radius hoses, broken hoses, plugged filter.  Also, sometimes the basic AN style plumbing fittings are too restrictive.  Unfortunately, the correct fittings are pricey.  Another thing to look for is loose fitting on the back of the gyro.  I have also seen the fittings over torqued, cracking the case housing and causing a leak.  

A friend recently reported a similar problem on his new to him aircraft.  Minor improvements in hose routing (slight collapse) and new filters seem to have cured this.  That said, a tired gyro can also cause this, as others have suggested.  Be careful when working with old hoses.  Flakes of rubber can FOD out a gyro or vacuum pump.  If the wiring behind the panel is a rats nest, be very suspicious of the hose routing.

this makes sense ill take a look at the hoses and routing.  thanks.

[Yetti]

Do you have access panels?  Pull that started chasing vacuum lines.  Also when were the filters changed last?

[Jim Peace]

On August 24, 2016 at 11:03 AM, TheTurtle said:

My artificial horizon will sometimes hang out cocked sideways until after my runup.  Vacuum gauge is showing vacuum even at idle.  The runup itself doesnt usually wake it up but sometime between runup and takeoff it will start working.  Sometimes it comes alive on startup but not usually.  Once it wakes up it seems to be accurate in flight and isnt lagging behind turns or climbs.

Same happened to me in my C.  I had the ADI overhauled at it has been fine since.  Had the DG overhauled as well and I have almost no precesion now.

[ArtVandelay]

Spruce has factory overhauled AIs for about $600, you simply do a swap, no down time.

[Yetti]

is it really noisy when it spins down after you turn the plane off?   I think it was about $400 to overhaul up Oklahoma way

[TheTurtle]

1 minute ago, Yetti said:

is it really noisy when it spins down after you turn the plane off?   I think it was about $400 to overhaul up Oklahoma way

doesnt seem to be.  all i hear is the T&B gyro spinning down.

[Guest]

10 hours ago, teejayevans said:

Spruce has factory overhauled AIs for about $600, you simply do a swap, no down time.

Just be sure that your core is an acceptable version or you'll be buying it outright.

Clarence

[jetdriven]

5 hours ago, M20Doc said:

Just be sure that your core is an acceptable version or you'll be buying it outright.

Clarence

and for that money, the G5 is not much more.  I used Aircraft Quality instruments in Tulsa, OK. it was around 350$ exch. they have around 600 hours on them and run great. The Clearview air pump filter has a lot ot do with this