The International Cessna^® 170 Association

Hello all..My question is regarding my intermittent AI. My aircraft 1956 172 (getting ready for the nose wheel jokes) Anyway, any recommendations before I send it out. Works most of the time but every once in a while its all over the place and even recently was spinning around after I landed and was taxing back to the ramp. Suction gauge reads 5 I have 2 venturis. thanks Pete

Check your static line filter first to insure it does not need changing - most do. Also check your static lines for any blockage such as water. Most probably an older AI with deteriorating bearings. I had a similar problem and wound up replacing the gyro.

Search the forums and you will find recommendations for overhaul shops. I had both my AI and my Turn/Slip overhauled by AQI in Wichita. I received several recommendations in regards to them form fellow members. I couldn't have been happier with their service, pricing and results. They called to verify they had received my instruments and asked a couple questions to make sure they knew exactly what work I wanted performed. The appearance of the re-conditioned faces was worth the money alone, but both instruments have worked flawlessly since that time, approx 2 years. Quick turn time as well.

Hope this helps.

Jughead

Your Attitude Indicator has a rough bearing which occasionally "hangs up" at the rough roller. It will need bearing replacements. Send it for overhaul. (Aircraft Quality Instruments is who does mine.)

Thanks everyone....

Hi I have another question regarding my AI...I pulled the panel back a little and noticed the filter(down on the right above the glove box). There are two ends where tubes would be attached. One end has a tube attached and one doesn't. A friend suggested that the other end on the filter should be closed off...I have no clue, if anyone could enlighten me I would appreciated it...thanks Pete

Your friend is correct, all air should flow thru the filter.

I'm probably wrong, but I think one fitting is the inlet to the filter and the other is the outlet from the filter to the instruments. Remember it is a vacuum system, the air source is cabin air.

Tim

Doesn't matter if you have two tubes on one end or a single tube at each end. Air is all suppose to enter through the white filter and exit each tube. If one tube is not used, it should be capped otherwise air will be sucked into the system through it bypassing the filter element.

I have the one pictured on the top. A tube is connected on the one side , nothing on the other side. Could the one side being open be the possible cause of my instruments not always being up to par...thanks

It still sounds like a rough bearing in the gyro.

If the other side of the filter isnt plugged, you're pulling unfiltered air thru your gyros. They will still work this way but may be the cause of the rough bearing (or other dirt inside the unit).

If you use it for IFR, have it sent out and overhauled.
If you fly VFR, stop looking at it

Thanks.....one more question....I notice a couple of the fittings on back of the AI and DG move around a little, are they supposed to be really tight. Thanks again

They are normally tight. Having said that if they move a little when you try to move them it is most likely fine so long as they aren't sloppy loose. Be careful should you try to tighten them. Over tightening will crack the instrument case rendering the instrument useless.

Thanks Bruce

Thanks all.....found a small tube connecting the 2 instruments not connected......all is well!