Mark89114

Failed AI indicator......and repair nonsense

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My backup AI decided to give up the ghost after only being repaired/overhauled 10/17.  I called the repair shop and they tried to tell me it was because I wasn't running enough vacuum, i.e. idle RPM, this low suction causes something called "washboarding" and then said this was an indication of vacuum pump failure.  Well I want to call BS, as my KI-256 is still working.  I want to claim BS as I have been flying for 30 years and no a little something and I mean very little.  I have never heard of a dry vacuum pump failing slowly, guess it is possible, but every one I have had just fails and it is recently new, maybe 300 hours.  He wanted to blame carbon dust was getting in there, well I have an inline filter between the vacuum pump and the instruments, so I know that likely isn't the issue.  I also replaced the "oily hose" from the standby pump to the main system so I don't think that should be the issue either.  The upside down is with system running and the spinning video is after shutdown, which I have never seen.  I guess the summary is I don't trust these guys work and will send somewhere else.  Any other shop recommendations?        Thanks, Mark

20190105_143834.jpg

Edited by Mark89114

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I have a low time sigmatec (200 hours to)I removed from my M you could have cheap...probably less than overhauling yours..pm if interested

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The AI took down the whole panel!   :)

Wait....

the still pic doesn’t do it justice... the video is more of a must see...

 

This is the back-up AI gone amiss?

Best regards,

-a-

C4233469-7975-4305-9427-8764448880D4.jpeg

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I have decided that all aviation anomalies can be explained with the phrase "Because I was inverted"

 

 

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You guys used to always be so helpful...….(sarcasm font)  

Sorry for the sideways picture......I only recently learned how to rotate a picture on wastebook…...if it doesn't do it for me automatically.  

 

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Hey Mark,

Does your O have a vacuum gauge?

or just the lights on the enunciator panel?

Somebody added a simple vac gauge early in my O’s life...

Other people probably wire a signal to the JPI...

With two independent vac pumps, it’s probably not a low vac issue... unless the regulator has gone TU...

Then again, the primary AI is running on vac... ‘air’ is probably printed on the face of the instrument...

As for gyro OH there are a few favored shops around here... One well known resource is a BK specific guy...

I’m not familiar with the others...

As for straightening up the pics... it has gotten much easier lately, but not part of MS yet...

Best regards,

-a-

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I just had that happen too. Paid an excessive amount to get the gyro overhauled. Within minutes it went crazy and eventually started spinning just like yours only faster. I verified the vacuum with my golden WWII Bendix Pioneer vacuum gauge and my vacuum was right on. The instrument shop checked my 80 year old gauge against their mercury column and it was dead nuts on.

I took it back and they rebalanced ithe gyro and now it works perfect. They never admitted there was anything wrong, but....

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15 hours ago, N201MKTurbo said:

I just had that happen too. Paid an excessive amount to get the gyro overhauled. Within minutes it went crazy and eventually started spinning just like yours only faster. I verified the vacuum with my golden WWII Bendix Pioneer vacuum gauge and my vacuum was right on. The instrument shop checked my 80 year old gauge against their mercury column and it was dead nuts on.

I took it back and they rebalanced ithe gyro and now it works perfect. They never admitted there was anything wrong, but....

The repair shops story was almost identical to yours.....couldn't have been anything we did.....

Pulled it out and sent it back to them.....will see if they provide warranty coverage.  

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On 1/7/2019 at 1:45 PM, Mark89114 said:

.  He wanted to blame carbon dust was getting in there, well I have an inline filter between the vacuum pump and the instruments, so I know that likely isn't the issue. 

Not sure I understand how a filter between the instrument and the vacuum pump helps the instrument... maybe the filter is on the suction side of the AI?

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In the vacuum hose between the AI and the vacuum pump. When you shut the engine down the instrument cases contain vacuum and the pump has none and the carbon dust migrates up into the gyros into the grease thats in the bearings and then causes failure

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On 1/8/2019 at 8:23 PM, jetdriven said:

In the vacuum hose between the AI and the vacuum pump. When you shut the engine down the instrument cases contain vacuum and the pump has none and the carbon dust migrates up into the gyros into the grease thats in the bearings and then causes failure

The filter is there in case of a pump failure. The cowling is pressurized and can push air(and dust) through the pump and into the instrument after the vanes break.

The situation you describe is impossible. Draw out a complete vacuum system on a napkin and think it over some more. ;)

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These are ridiculous times. Aviation is so conditioned to insane prices...Ai prices are a good indicator.

I applaud the feds making it easier for solid state to make the way into the cockpit. With items like the AV20 and dynon product in lieu of paying 1500 for just an overhaul on a non primary gyro, things get better. Garmin has exploited technology like the G430 for so long and kept prices at such a ridiculously high price I just can’t justify spending money on the brand.

Perhaps if you only sold a few hundred items the high cost would be justified. With Garmin pushing for adsb to be the standard, and subsequently monopolizing the market and suing others, I like to see competitors step up.

Good luck on your AI!


Sent from my iPad using Tapatalk

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10 hours ago, N231BN said:

The filter is there in case of a pump failure. The cowling is pressurized and can push air(and dust) through the pump and into the instrument after the vanes break.

The situation you describe is impossible. Draw out a complete vacuum system on a napkin and think it over some more. ;)

Perhaps you can explain why my gyros has carbon dust in the bearings even though the pump is older than the Gyro and has not failed?

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