Attitude Indicator / Suction Gauge

[George]

Good grief..... Less than a month into aircraft ownership and the attitude indicator appears to be going south and will need to be replaced. Works for awhile and then wanders into steep turns in level flight than back to normal??? Spruce quoted $2400 for replacement.. I'm guessing the high price is due to the STEC autopilot in the aircraft? Can these units (Century artificial horizon 400c-1 model) be overhauled and where might I send it if it can be overhauled?

Along the same lines...What should my suction gauge be reading at idle? My gauge is reading 3 at idle (1000rpm)? In the green during flight.

Thanks a bunch,

GHW

[Andy95W]

If you do have an STEC autopilot, then your attitude indicator has nothing to do with it. STECs use the turn coordinator. 

3" vacuum on the ground and in the green in the air sounds right. 

Overhauled is the way to go, far cheaper than new and lots of instrument shops can do the work. 

Finally- if you do have an STEC autopilot but a Century attitude indicator, you can probably negotiate a swap for a standard non-autopilot AI at a reduced price. 

[jetdriven]

Aircraft quality Instruments, Wichita ks. About 500$ for an OH

Edited November 18, 2016 by jetdriven

[Bob_Belville]

+1 for AQC who o'hauled my RCA22-7 AI in July for $396 - this includes making it pretty. (plus $112. shipping and R&R.) I briefly considered switching to an electric b.u. but this is a back up unit behind an Aspen and there are better ways to spend money.

[carusoam]

One month into ownership...

It might be time to do a lot of web searching for the specific devices you have.  To know what drives What and how they are connected is important.  Especially when you are flying in IMC.

vacuum pumps, lines and filters can all be suspect.

How many hours are on each of these devices will give you a hint of what to expect.  You may want to start with reading the log books to see the last time these things have been swapped out or maintained...

Since your AI is behaving in a less than friendly manner, make sure your back-up system is working properly too.  Be familiar with how it works and where it gets its power from.

Avoid IMC completely until you have things more known, and less unknown.

Best regards,

-a-

[Bob - S50]

Here is another thought.  If you have an STEC autopilot based on your TC, and you say it is going to cost you $2000 to buy an overhauled ADI replacement, you might also consider replacing your ADI with a Garmin G5 which lists for $2149.  If your ADI is the only vacuum driven equipment, you could then remove the vacuum system and reduce weight as well as future maintenance expenses.

[George]

Appreciate the replies...Will try and have the unit overhauled to keep costs down for now. I do like the idea of the G5!

GHW

[jetdriven]

Just beware that many overhaul shops charge you $1000 or more to overhaul that, and in that case the G5 would be cheaper. you also don't always know it's gonna cost 1000 bucks until after is already done and I have a credit card and they already charged it....it's a common repair station scam

[George]

Purchased overhauled RCA 22-7 A/I  unit from source in ICT. I still had some issues with the new overhauled.. After adjusting the artificial plane in level flight the would  A/I show a climb in a descent and vice versa. In addition the "gyro horizon" in the unit vibrates to the point of making the display blurry. Spoke with the folks in ICT and the built another one for me and we exchanged units again. And now the recently exchanged unit after about 15 hours of operation is displaying the same problems as the unit we exchanged mid November.

-Suction in green 

-Vacuum filter changed with original exchange unit mid November.

Might we be doing something wrong in the installation...not much to it or is there?

Too much aircraft vibration?...seems to be about normal..only have about 60 hours in this plane since purchase.

Or did I get two overhauled lemons from ICT? 

Thanks again for inputs

 

GHW

.

[carusoam]

As far as engine vibration...

Two sources...

1) dynamic prop balance...

(Not O360 related) 2) how deep can you go LOP?  At low altitude, really deep is about 75 - 80 °F LOP....  this would be a good sign of good injector balance...

3) some oddity related to engine mount donuts...?

4) broken weld on an engine mount...

I would expect that vibration from a low time IO550 is near nil.  But measuring it would be the only way to tell.  An O360 has considerably more vibration.  Measuring would be helpful.

PP advice, not a mechanic...

Best regards,

-a-

[George]

10 minutes ago, carusoam said:

As far as engine vibration...

Two sources...

1) dynamic prop balance... on the new TopProp..?

2) how deep can you go LOP?  At low altitude, really deep is about 75 - 80 °F LOP....  this would be a good sign of good injector balance...

3) some oddity related to engine mount donuts...?

I would expect that vibration from a low time IO550 is near nil.  But measuring it would be the only way to tell.

PP advice, not a mechanic...

Best regards,

-a-

No prop balance since overhaul 2006 (Hartzell)

LOP...well that's another issue I need to figure out...Engine seems to already be running lean without leaning..GEM 602 showing temps on all cylinders above asterisk on GEM and have not even touched mixture. Yesterday at 3000ft 23/2300 FF was 9.6 w/o leaning. Manual indicates FF around 10 at 2500ft.

Annual in February...have them look at mounts...

Thanks

GHW

[carusoam]

Unusable data previously posted... in this spot...

George, I also updated the previous post, as I may have mixed a few ideas together...

The O360 has two sources of flow imbalance...

different uncontrolled airflow to each cylinder.

different uncontrolled fuel flow to each cylinder.

An IO550 by comparison...  balanced air intakes (curvy pipes) and balanced fuel injectors (selected by FF to each cylinder and changed if not near perfect)

The carburetor is a real challenge because of the All in one flow spread toward four separate intakes.

LOP for the O360 is hard to come by without FF and good EGT instrumentation.

There are a significant number of people now using engine monitors and FF instrumentation around here with O360s.  It is more likely to exchange data than it was just a couple of years ago...

Best regards,

-a-