Attitude Indicator and Directional Gyro faults

[Mooney-Shiner]

6 minutes ago, StevenL757 said:

Personally, I wouldn't waste any more time or money on this, including aircraft downtime whilst you troubleshoot problems.

Not sure why you want to wait "50 or 100 hours" before any upgrades, but I would get this going now...especially given the long lead times for some components as well as shop lead times.  Get a reliable ADI, get a reliable backup for it, get rid of the vacuum system (unless needed for vacuum-operated speed brakes, if you have them), and stop the bleeding.

Good point on throwing good money after bad...

The reason for my "wait and see" approach is that because I'm only 40 hrs into my ownership of my 67F and I'm not sure whether I will have any major capital setbacks with this old plane in the near future. If "suddenly" I will facing major expenses, I will consider cutting my losses and getting out of the plane ownership and settle for renting/partnership until better time in the future.  This is why I wanted to wait before throwing major money for Aspen or at least Uavionix AV-30. Although replacing the DG with AV-30 is tempting right now. 

Considering the cost of overhaul, I'm considering just buying used DG with 90 days warranty for $200-300 and calling it a repair. I'm fine with taking a risk of failure after 90 days.

[StevenL757]

If that's your situation, I understand.  My goal with my prior Ovation (and now my present one) is to make the airplane whole before any major panel upgrades, so I agree there.

[Mooney-Shiner]

1 hour ago, StevenL757 said:

If that's your situation, I understand.  My goal with my prior Ovation (and now my present one) is to make the airplane whole before any major panel upgrades, so I agree there.

Yes, Sir. I have the same logic as yours.  The structural items first (engine, frame, min VFR eqpt requirements), then advanced avionics

[carusoam]

7 hours ago, ukrsindicat@yahoo.com said:

Yes, Sir. I have the same logic as yours.  The structural items first (engine, frame, min VFR eqpt requirements), then advanced avionics

For swapping out the old worn device… and getting a less worn device…. Send a message to @Alan Fox…

He sees a lot of instruments while searching for radios…

Best regards,

 -a-

[Mooney-Shiner]

Update: 

We pulled the Directional gyro and sent it to Naylor Avionics shop in Gainesville, FL.  Also will have him check out my old Weston electrical switch for Lo/Hi Vac lights, which I suspect is not working. 

To continue flying VFR,  connected the DG’s exhaust and intake together to prevent the vacuum leak and keep my AI running. 

We went flying today and, for whatever reason, my attitude indicator that previously worked fine decided to sag like it was not getting a vacuum… can’t win here… I need to install a vacuum gauge in the panel, but thats a separate topic. 

We decided to re-engineer this temporary arrangement.  We individually plugged the inflow and outflow hoses and now the attitude indicator works perfect… Mystery...

More to follow once we will fly to pick up the re-built DG in Gainesville. 

Edited February 12, 2022 by ukrsindicat@yahoo.com

[PT20J]

I once used a bolt for a plug and it leaked. Finally dawned on me to use a longer bolt with a shank to tighten the clamp against. I had originally used a shorter bolt that was all thread and clamping on the threads was the source of the leak.

Skip

[BobbyH]

Thanks for the discussion, my 66' M20E is having similar AI and DG issues.  I'm assuming the vac pump but haven't put a gauge on it yet.  It still has the PC leveler plumbing and actuators without the yoke controls (previous owner upgraded to S-Tec sys 50) that I'm also concerned about potential leakage.  I would love to upgrade to G5s or modern avionics but the budget is a little too lean. 

It's good to know the low vac light should come on prior to starting the engine, makes perfect sense.  I'll pay special attention to that next trip to airport. 

On 2/11/2022 at 9:20 PM, ukrsindicat@yahoo.com said:

To continue flying VFR,  connected the DG’s exhaust and intake together to prevent the vacuum leak and keep my AI running. 

ukrsindicat, any resolution with your rebuilt DG? 

[DCarlton]

Ole school opinion...  there's nothing wrong with vacuum gyros and steam gauges.  Over a period of about 18 years, I've overhauled or replaced every gauge on my F's pilots side panel.  It looks like a rats nest behind the panel but these systems aren't that complicated.  It takes patience and time studying the schematics but you can figure it out.  I have a vacuum gauge and the original Hi/ Lo Vac warning lights.  Keep them both.  These mechanical systems were elegant, simple and generally reliable and have no backup batteries, software or electronics.  I'm still a fan.  I may install an AV-30 at some point in the AI position just for fun and to clean up the rats nest but that's the only reason.  I'm satisfied with my steam gauges.  No rush at all to upgrade.  Just get it fixed and fly. 

Edited March 10, 2022 by DCarlton

[MikeOH]

32 minutes ago, DCarlton said:

Ole school opinion...  there's nothing wrong with vacuum gyros and steam gauges.  Over a period of about 18 years, I've overhauled or replaced every gauge on my F's pilots side panel.  It looks like a rats nest behind the panel but these systems aren't that complicated.  It takes patience and time studying the schematics but you can figure it out.  I have a vacuum gauge and the original Hi/ Lo Vac warning lights.  Keep them both.  These mechanical systems were elegant, simple and generally reliable and have no backup batteries, software or electronics.  I'm still a fan.  I may install an AV-30 at some point in the AI position just for fun and to clean up the rats nest but that's the only reason.  I'm satisfied with my steam gauges.  No rush at all to upgrade.  Just get it fixed and fly. 

I just have to chime in and agree with this 100%!  I've owned my Mooney for 5 years and have only recently started to see my AI become slower to come up (i.e it's giving me fair warning).  I have a stone-simple vacuum backup (intake manifold system).  I, too, have the high-low vacuum warnings, and flags in the instrument.  While I read here about how 'unreliable' a vacuum system is, and therefore how the safe solution is to run out and spend a small fortune on 'glass' and AHRS, etc. to dump the vacuum system....the PROBLEMS being discussed here seem to revolve around weird failures, software glitches, version updates, etc. with the new 'reliable' electronic stuff.  As a career EE, this does NOT surprise me at all.

Thanks, but I'll stick with what sucks!

[A64Pilot]

I did all of my training back in the 80’s, and am very comfortable with the old school stuff, that along with Garmin and others planned obsolescence has me liking my ancient King stuff even more, especially as it can usually be picked up cheap from people upgrading avionics. I paid maybe $200 for a new looking KT-76C for instance and kept the -A as a spare.

I’m sure that soon Garmin will orphan my 430W, but I’ll still be able to get the King stuff repaired locally when they do.

Sure new stuff is cool. but it often takes a lot of flying away while the aircraft sits in the shop and can be very expensive for what it actually gives you, then add in its a completely whole another thing to learn, and after a few decades of flying your just not as excited about the latest greatest thing, I guess that’s one definition of growing old?

 

But do get a cheap vacuum “nickel” gauge, as with most things mechanical a pump usually gives fair warnings before failure, if it needs adjusting one day because of slightly low vacuum, consider a new pump instead of adjusting to compensate for the wear. 

Edited March 10, 2022 by A64Pilot

[A64Pilot]

If I start flying a lot of hard IFR again, I’ll probably get an AHARS that will drive my Ipad with Foreflight or similar, sure it’s not a legal instrument but if the primary goes, I feel it will get me to the ground.

However those apps you download for an Iphone etc will NOT, there is no AHARS in an Iphone, just accelerometers etc. Try one, put yourself in a constant standard rate turn, over time the Iphone will show level flight.

Edited March 10, 2022 by A64Pilot

[A64Pilot]

I’ve had for years a 696 and a GDL-39, I was running the Ipad with foreflight bluetooth to the GDL-39, with as you say occasionally some issues that resolved themselves the other day.

However when I looked at the Ipad connections I noticed it’s only connection was to the Uavionics ADSB via WIFI, so it must be getting GPS and ADSB and Wx data through the ADSB, and I thought the Wifi connection was only for set up?

Anyway it looks like money wise the Sentry ADSB  receiver with an AHARS for $500 is the best buy and it’s also a CO monitor. It would also be a completely redundant system to the GDL / 696 including separate power supplies.

https://flywithsentry.com

Edited March 10, 2022 by A64Pilot

[Mooney-Shiner]

On 3/9/2022 at 6:05 PM, BobbyH said:

Thanks for the discussion, my 66' M20E is having similar AI and DG issues.  I'm assuming the vac pump but haven't put a gauge on it yet.  It still has the PC leveler plumbing and actuators without the yoke controls (previous owner upgraded to S-Tec sys 50) that I'm also concerned about potential leakage.  I would love to upgrade to G5s or modern avionics but the budget is a little too lean. 

It's good to know the low vac light should come on prior to starting the engine, makes perfect sense.  I'll pay special attention to that next trip to airport. 

ukrsindicat, any resolution with your rebuilt DG? 

Hello, Bobby, sorry for the delay. I was pretty busy last couple of weeks because I have family in East Ukraine. 

I got my DG back from Naylor (Gainesville, FL) and finally installed it today. The overhauled DG is performing perfectly. No error at all after 5 minutes. According to overhaul notes, the unit was out of balance and caused the error of 2 degrees every minute (see above). Total price for overhaul was $425 plus replacement of backplate $45 plus UPS freight $30 plus tax.

Just a note of caution: be careful torquing the plumbing fittings on the back plate of DG or AI, overtorquing will crack the backplate.

[jamesm]

Well  with all the Aspen/Garmin/AV30/AV20/RCA electronic ADI  HSI out there should be plenty of used /pre-owned  Vacuum pumps, Vacuum regulators,and  Vacuum driven ADI HSI, vacuum servo for the step to be had.

James '67C

[Mooney-Shiner]

On 12/13/2021 at 5:51 PM, Igor_U said:

No,

By pushing the light you are testing only a light bulbs. Those are (Low and Hi) connected to Sigmatec 22-1280-04 Vacuum switch. If one is in working condition, with master on, Low light should illuminate (engine off). If not, something is wrong, switch, wiring, etc... Sigmatec switch is quite expensive... I found my broken during the pilot's panel upgrade and removed it. I have a vacuum gage...

I finally got to troubleshoot my vac switch(made by Weston, but looks like Sigma-Tec). I untied it from the vac system (still connected to wires) and pulled the vacuum on it with my mouth. The Master switch was on, but the engine was off.  The Hi light came up as I was pulling a vacuum. I tried to lightly blow into the switch to cause a “Low” warning light reading, but no light reaction. I know the both of my light bulbs work, because they did light up when I pressed on them. I wonder if the is a way of disassemble the switch to check for the right contacts.