Compass Question.

Tom-D

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Tom-D
A thread running now prompted me to post this question.

almost every compass I know of has a port in the very top that allows fluid to be added.
We add air to tires, we add oil to engines, and call it servicing. If I remove the cap made for that purpose on a compass, and add fluid, did I repair The compass or service it?
 
Service it. A mag compass doesn't fit the definition of an "instrument" per Part 1.
How so?
Instrument means a device using an internal mechanism to show visually or aurally the attitude, altitude, or operation of an aircraft or aircraft part. It includes electronic devices for automatically controlling an aircraft in flight.

It does use an internal device to show visually the attitude of the aircraft. Remember the attitude is about all axes, vertical included.
 
It does use an internal device to show visually the attitude of the aircraft.
No, it says "internal mechanism" not "internal device." So by definition, what "mechanism" is involved in the operation of a mag compass?
 
Why would this be any different than adding oil to the engine or adding brake fluid?
 
No, it says "internal mechanism" not "internal device." So by definition, what "mechanism" is involved in the operation of a mag compass?
I believe that the FAA believes that the rotor (that has the numbers on it) is a 1 piece internal mechanism. making it an instrument.

are we still servicing ?
 
Why would this be any different than adding oil to the engine or adding brake fluid?
Because there are a whole bunch of folks that believe that a compass is an instrument, which require a certified instrument to repair.
 
Because there are a whole bunch of folks that believe that a compass is an instrument, which require a certified instrument to repair.

If the compass works properly and has no signs of leakage, I can’t see where you repaired anything by replenishing fluid. “Inspected compass for security, leaks and proper operation, serviced with .5 gram fluid.”
 
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Hmm, I don't know about requiring an instrument repair shop. But, they're dirt simple to work on. If you do add fluid, submerge it or use a filling aid to get as much air out (and fluid in) as possible. Oh, but then you'd probably want to swing it again, so....
 
I believe that the FAA believes that the rotor (that has the numbers on it) is a 1 piece internal mechanism.
Everyone is entitled to their opinion. I'll take door #2, still servicing. But then again I believe a pilot can touch up paint on props too :)
 
Everyone is entitled to their opinion. I'll take door #2, still servicing. But then again I believe a pilot can touch up paint on props too :)

Oh SNAP!!! :)
 
Just top it off and be done with it. Enter it in the log or don't. If it isn't logged, it didn't happen.
 
Ok. We’re talkin about a Whiskey Compass here. Now, if someone is pizzen ya off and ya need a drink, are you sevicin yer brain or are ya repairin it? You’re servicing it. Therefore, when you add Whiskey to a Compass, you are servicing it.
 
Ok. We’re talkin about a Whiskey Compass here. Now, if someone is pizzen ya off and ya need a drink, are you sevicin yer brain or are ya repairin it? You’re servicing it. Therefore, when you add Whiskey to a Compass, you are servicing it.

Depends on the day. Every so often a dram of whisky most definitely constitutes a repair to the ol’ thinker.
 
The answer to this question is critical. Think of the children that could die if someone filled up their compass without it being allowed in the regulations!
 
There are stories of A&P mechanics losing their licenses over filling whiskey compasses. Personally? Don’t care. I trust my mechanic to do what he feels is right. My Cessna’s compass is there for the regs. I don’t use it. My exp doesn’t even have a compass. The dang things aren’t worth much in the GPS era.
 
Um, someone refilled mine, but it leaked back out, so I replaced it. It's a stupid simple fix, I'm told.
 
Compasses are cheap, a brand new one is under $200 with internal lighting. The 177 and 182 have brand new ones.
 
I probably need to top mine off, but I can’t find the filler hole.

10-04173m.jpg
 
If you do add fluid, submerge it or use a filling aid to get as much air out (and fluid in) as possible. Oh, but then you'd probably want to swing it again, so....

That's what the Airpath compass service manual requires: submerging it, then installing the rear cover while submerged.
 
A magnetometer contributes info to my G3X. Way more accurate than a compass.
Does the FAA recognize that as the "magnetic direction indicator" as 91.205 requires? If so, that's nice. In Canada the regulation says this:

(d) a magnetic compass or a magnetic direction indicator that operates independently of the aircraft electrical generating system;

So we're stuck with the compass and an annual calibration besides.
 
Does the FAA recognize that as the "magnetic direction indicator" as 91.205 requires?
Yes. There's an AC somewhere that explains the change. With new aircraft having magnetometers, FOGs, and other new tech systems some of the FARs are slowly being amended. That was the reason Part 23 was condensed and a number of certification requirements were moved into ACs for greater flexibility.
 
That's what the Airpath compass service manual requires: submerging it, then installing the rear cover while submerged.
The little filler gadget that goes over the filler hole works better.
 
I think that it would only be a problem if someone serviced the "whiskey" compass with whiskey.
 
I once had to rebuild a compass. The rebuild kit was a new diaphragm and a quart of white kerosene. I replaced the diaphragm, checked the jewels that the axle spins on and submerged it in the fluid. Tighten the screws while the compass is submerged to ensure no air bubbles and that's it. Done.
 
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