Standby Compass Leaking

[GeneralT001]

Was up at 12,500' today and smelled something akin to fuel. Eventually located a drip coming from the standby compass. I'm guessing the reduced pressure caused the issue. Is this fixable (tighten screws?) or is it time to replace...as in are they a sealed unit?

 

 

[MisfitSELF]

It's likely between age or vibration that a seal is wore out.  They sell refurb kits for the old school compasses but be careful to to not screw down the case down too much or you'll crack the glass (which is $40 btw, ask me how I know....)

BTW, what's a "standby compass"?  Do you mean your primary (or only) magnetic compass or do you have two magnetic compasses in your aircraft?

I ended up after much flailing with my old compass in which I replace the seals, fluid, glass, and mount -- installing "SIRS Compass"

Bruce

P.S.  If you're anywhere near the SO CAL area and can get to L00 (Rosamond Skypark).  I'll happily give you what I have in regards to the Airpath Compass if that's what you have.  I may have the refurb kit, fluid and some parts still laying around.

 

Edited January 14, 2022 by MisfitSELF

[MisfitSELF]

https://www.aircraftspruce.com/pages/in/compasses_airpath/repairkit.php

 

[EricJ]

It has probably gotten an air bubble in it that tries to expand at higher cabin altitude, so that's when they drip.

+1 on the repair kit, but they're kinda hard to get right, i.e., no bubbles, unless you reassemble it submerged in the compass juice (compass fluid).   Also, it is not actually legal for even an A&P or IA to do this, it *should* only be done at a properly authorized instrument shop repair station.    However, this is a job very often done by hangar fairies and some are quite experienced at it.

 

Edited January 14, 2022 by EricJ

[LANCECASPER]

1 hour ago, GeneralT001 said:

Was up at 12,500' today and smelled something akin to fuel. Eventually located a drip coming from the standby compass. I'm guessing the reduced pressure caused the issue. Is this fixable (tighten screws?) or is it time to replace...as in are they a sealed unit?

 

 

Congratulations - that's a long trip. How did it go?

https://flightaware.com/live/flight/CGTVV

[N201MKTurbo]

My hanger elves (fairies is not PC these days) have told me the best way to fill a compass is to fill it with compass fluid, till there is a meniscus of fluid above the fill port, put your finger over the fill port and turn it upside down and gently shake it to get all the bubbles out from under the compass card. Then slowly turn it right side up and work the bubbles back to the fill port. Use a coffee stirrer to add the last bit of fluid until there is a meniscus of fluid above the fill port. carefully bring the plug into the fluid and screw it in. Rotate the compass every which way and make sure there are no bubbles inside. If you find any repeat the above procedure until there are no bubbles.

[Guest]

A C21-100 compass diagram and some compass fluid.  Once the compass is removed from the mounting cup, remove the aft cover to replace the diaphragm.  Refill the compass through the top filler plug by submerging in compass fluid.

Glad you’re home with the new plane

Clarence

[EricJ]

1 hour ago, N201MKTurbo said:

My hanger elves (fairies is not PC these days)...

I see no reason not to be inclusive about the hangar creatures. 

[jaylw314]

4 hours ago, MisfitSELF said:

It's likely between age or vibration that a seal is wore out.  They sell refurb kits for the old school compasses but be careful to to not screw down the case down too much or you'll crack the glass (which is $40 btw, ask me how I know....)

BTW, what's a "standby compass"?  Do you mean your primary (or only) magnetic compass or do you have two magnetic compasses in your aircraft?

 

For those with the King slaved HSI, they are slaved to a magnetometer.  As such, the HSI counts as the required magnetic compass, and the whiskey compass is just a backup.

[GeeBee]

4 hours ago, MisfitSELF said:

It's likely between age or vibration that a seal is wore out.  They sell refurb kits for the old school compasses but be careful to to not screw down the case down too much or you'll crack the glass (which is $40 btw, ask me how I know....)

BTW, what's a "standby compass"?  Do you mean your primary (or only) magnetic compass or do you have two magnetic compasses in your aircraft?

I ended up after much flailing with my old compass in which I replace the seals, fluid, glass, and mount -- installing "SIRS Compass"

Bruce

P.S.  If you're anywhere near the SO CAL area and can get to L00 (Rosamond Skypark).  I'll happily give you what I have in regards to the Airpath Compass if that's what you have.  I may have the refurb kit, fluid and some parts still laying around.

 

+1. The SIRS compass is the bomb. Much better unit, 4 compensating magnets, a brass rather than rubber diaphragm, silicon fluid. Standard equipment on Airbus. With 4 compensating magnets, it swings really fast and tight. When mine dies, it will be replaced with a SIRS unit. 

[carusoam]

Things I learned today…

1) Hangar fairies have rights, and their unionized…

2) The magnetometer attached to an HSI counts as a compass…

3) If you can fly an Airbus with a compass, that compass will work in a Mooney too…

4) Makes me wonder… if I take my Mooney compass in an Airbus…. Does that make me able to fly the Airbus too….? 
 

5) Looks like GT has arrived at home with his new bird?!?!?!

 

+1 for getting the kerosene kit and seals and diaphragm from Airpath… if you have an airpath compass… really low cost for some reason…

Super cold weather, combined with age… likes to let them drip a drop of kerosene… it probably leaves a spot on the right leg of your Levi’s…

The chance of seeing the drip while flying is incredibly small… but, only takes a few to have the air bubble appear in the window…

https://www.aircraftspruce.com/catalog/inpages/ecocomseal2.php

PP thoughts only, not a mechanic…

Best regards,

-a-

[amillet]

2 hours ago, jaylw314 said:

For those with the King slaved HSI, they are slaved to a magnetometer.  As such, the HSI counts as the required magnetic compass, and the whiskey compass is just a backup.

So I can legally remove the center post factory installed wet compass? (I do have the slaved HSI)

[EricJ]

9 minutes ago, amillet said:

So I can legally remove the center post factory installed wet compass? (I do have the slaved HSI)

Unlikely.   The Seminole that I did my MEI training in had no compass, but it came that way from the factory.   Piper sent a special letter to the flight school about it because their chief instructor wouldn't fly it without a compass. 

So there is a certification basis for not having a compass, but I think it still requires multiple sources and independent power sources for each.   The Seminole had a new G1000 system as well as an Aspen backup, and I think they both had their own magnetometers and backup power sources.    So eliminating the compass can be done, but I don't think it's trivial.   That said, it's not like a compass is expensive or heavy or takes a lot of maintenance, and they work no matter what, so I don't know why anybody would be eager to get rid of one.   I feel the same way about the inclinometers, though (the ball in a T&B), because they're cheap and small and light and take no maintenance and work no matter what, but you don't see them in new airplanes, either.

Since our Mooneys were certified under CAR3 there may be different hoops to jump through, I don't know, but I don't think you can ditch a passive compass just because you have a magnetometer, or everybody with a GMU11 or one of the legacy HSI systems could have done so.

[GeneralT001]

6 hours ago, LANCECASPER said:

Congratulations - that's a long trip. How did it go?

https://flightaware.com/live/flight/CGTVV

Hi,

Not without its challenges :). A VFR flight that was pretty much IFR from the get go. Even shooting an approach (VOR/DME) at night for the first time in like forever...with a night landing...only my 2nd landing in the Mooney....I think. The engine and prop performed well and showed no issues. I did a quick radar vectored ILS (VFR) upon leaving Calgary as the wx at destination was not good. I'm glad I did though as it showed that the GS portion of the ILS receiver was not useable but the localizer was good.

I used an iPad and Garmin Pilot for all the cross country NAV and even for an Arrival I was given and it performed very well......really highlites the need for a fully integrated NAV system though such as a Garmin GTN750Xi/GTN650Xi. The Bendix King stuff has got to go at some point. There are a few other little snags that need to be addressed ASAP...but thats the joy of ownership

The video below (iPhone so forgive the production quality) shows the plane also needs a good dusting and a new glare shield :). This is where I was up at 12,500'...contemplating my chances of survival should the engine fail while over the cloud

It was a busy time trying to get used to the aircraft and keeping up with ATC on arrivals and departures...missing a co-pilot

 

[GeneralT001]

3 hours ago, GeeBee said:

+1. The SIRS compass is the bomb. Much better unit, 4 compensating magnets, a brass rather than rubber diaphragm, silicon fluid. Standard equipment on Airbus. With 4 compensating magnets, it swings really fast and tight. When mine dies, it will be replaced with a SIRS unit. 

Yes, I think this is the way I'm going and will be ordering shortly.

Edited January 15, 2022 by GeneralT001

[carusoam]

Great video GT!

That is a lot of open area out your way…

Best regards,

-a-

[GeneralT001]

2 hours ago, carusoam said:

Things I learned today…

1) Hangar fairies have rights, and their unionized…

2) The magnetometer attached to an HSI counts as a compass…

3) If you can fly an Airbus with a compass, that compass will work in a Mooney too…

4) Makes me wonder… if I take my Mooney compass in an Airbus…. Does that make me able to fly the Airbus too….? 
 

5) Looks like GT has arrived at home with his new bird?!?!?!

 

+1 for getting the kerosene kit and seals and diaphragm from Airpath… if you have an airpath compass… really low cost for some reason…

Super cold weather, combined with age… likes to let them drip a drop of kerosene… it probably leaves a spot on the right leg of your Levi’s…

The chance of seeing the drip while flying is incredibly small… but, only takes a few to have the air bubble appear in the window…

https://www.aircraftspruce.com/catalog/inpages/ecocomseal2.php

PP thoughts only, not a mechanic…

Best regards,

-a-

I kept the aircraft hangered for the RONs so no cold soaking at all. And the heat that that aircraft puts out....I had to keep the vent almost fully closed for most of the flight...even over the bald ass prairies where it was like 300 below zero......which raises another concern...that hot air blowing directly on the fuel selector...it gets hot to the touch...is that normal?

[carusoam]

10 minutes ago, GeneralT001 said:

I kept the aircraft hangered for the RONs so no cold soaking at all. And the heat that that aircraft puts out....I had to keep the vent almost fully closed for most of the flight...even over the bald ass prairies where it was like 300 below zero......which raises another concern...that hot air blowing directly on the fuel selector...it gets hot to the touch...is that normal?

Oddly, that is normal…

there is a recent thread around here where Ross did some temperature studies on his M20F’s air supply temps….

The F’s system is only similar to the J….  But the temps are interesting and apply to all of our planes…. EGT derived with a heat muff on the muffler…

 

If you don’t have a CO monitor… now would be a good time to add one…. Many portable devices used around here….

My heat system warms the fuel selector in my O as well…  I was surprised the fuel flow didn’t keep it cool…

 

If you run only hot air, and don’t blend any cold air with it… it can get kind of close to boiling water temp….

Find Ross’ pics…

Best regards,

-a-

[GeneralT001]

2 minutes ago, carusoam said:

Oddly, that is normal…

there is a recent thread around here where Ross did some temperature studies on his M20F’s air supply temps….

The F’s system is only similar to the J….  But the temps are interesting and apply to all of our planes…. EGT derived with a heat muff on the muffler…

 

If you don’t have a CO monitor… now would be a good time to add one…. Many portable devices used around here….

My heat system warms the fuel selector in my O as well…  I was surprised the fuel flow didn’t keep it cool…

 

If you run only hot air, and don’t blend any cold air with it… it can get kind of close to boiling water temp….

Find Ross’ pics…

Best regards,

-a-

Yes thanks....I did get one of those Sensorcon CO detectors. I didn't blend any cold air in so I'll definitely do that next flight.

[jaylw314]

3 hours ago, amillet said:

So I can legally remove the center post factory installed wet compass? (I do have the slaved HSI)

I do recall reading some FAA letter somewhere which specifically stated that the day VFR requirement for magnetic compass could be met by any magnetic instrument that met that function, so there does NOT actually have to be a floating doohickey that points north somewhere in the plane.  On the other hand, your IA may have something to say about getting rid of the whiskey compass!

[N201MKTurbo]

11 hours ago, EricJ said:

I see no reason not to be inclusive about the hangar creatures. 

I agree, I really don’t care who sneaks into my hangar at night to fix my plane as long as they do a good job.

[GeneralT001]

On 1/14/2022 at 3:51 PM, M20Doc said:

A C21-100 compass diagram and some compass fluid.  Once the compass is removed from the mounting cup, remove the aft cover to replace the diaphragm.  Refill the compass through the top filler plug by submerging in compass fluid.

Glad you’re home with the new plane

Clarence

How do you remove it from its mounting cup?

[jetdriven]

On 1/15/2022 at 1:04 AM, GeneralT001 said:

Yes, I think this is the way I'm going and will be ordering shortly.

Problem is that SIRS doesn’t sell the Mooney mount anymore 

[Guest]

7 hours ago, GeneralT001 said:

How do you remove it from its mounting cup?

There is a screw in the front of the cup, you need a really short screwdriver to fit between the cup and the windshield. Back the screw out a little, then use it to push the compass out of the cup, gently pull it out extending the lamp wire, use a small flat screwdriver to remove the lamp retaining screw with is under the lamp access door.

Clarence

 

[GeneralT001]

16 hours ago, M20Doc said:

There is a screw in the front of the cup, you need a really short screwdriver to fit between the cup and the windshield. Back the screw out a little, then use it to push the compass out of the cup, gently pull it out extending the lamp wire, use a small flat screwdriver to remove the lamp retaining screw with is under the lamp access door.

Clarence

 

Done. Funny that the new AirPath I bought (exact same compass) did not have a screw in the back? Anyway, I did the reseal but have decided that I'm going to get a panel mount AirPath and forget about the shroud bar one...will give a cleaner look and better visibility  Legal or not...not worried