How much does a PA28 compass weigh?
 

How much does the compass for a PA28 weigh and what is the lever arm? (My instructor asks me to find out the answers to such silly questions!)

I'm convinced this must be ATPL knowledge as it's not in my PPL text book! I've looked in the POH for a PA28 Warrior, but still can't find it out.

Anyone know the answer?

It's certainly not ATPL knowledge. Can't think why you'd want to know this. (Not that this would stop it being examined for ATPL, but that's not the point!)

I have absolutely no idea about the weight. The best thing might be to contact an avionics supplier. Or possibly your local PFA group - someone must have a compass waiting to be installed in a home-built that they can weigh for you. Of course this won't give you the weight of your particular compass in your particular PA28, but.....

The lever arm you can find out from the POH. It is measured in inches forward or aft of the datum. Normally you just treat these as meaningless numbers - but the POH will actually tell you where the datum is, then you can measure (with a tape measure) the distance from there to the compass.

I'd be more interested in hearing why your instructor wants you to find this out than I am in hearing the answer the to the actual question!!!

FFF
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Not such a bizarre question really - the info is there if you look for it.

In the C310 the compass weighs-in at 0.6lbs and has an "arm" of 13 inches.

All of this data contained in the W&B record for the aircraft, and updated whenever anything is changed/added/removed.

The instructor is teaching a principle, nothing more nor less.

If you know how/where to get this information and how/where to use it, you will be able to safely do W&B calcs on more "normal" items such as fuel and passengers.

Are you looking in the aircraft's CAA-approved POH or an "abridged" flying-school version?

Have you checked the aircraft's W&B records?

Check in the manufacturer's a/c manual (handbook/operating manual/whatever it's called where you are). There will be a section to do with installed equipment that gives weight & arm for all equipment items.

Your instructor is probably getting you to find your way around the POH.

My Warrior II POH has the answer on page 6-25, item 28

P

Hmm, don't recall ever seeing this in a POH. But it seems like I've been out-voted. I think it's more fun to find the information out without using the POH though :D :D :D

FFF
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Typical pilot, I'll bet you've never read anything but the handling section ;-)

G

You sure that your instructor hasn't been sniffing the alcohol in the compass? :D

The idea of getting you to look at the flight manual is a good one but I think that questions of a more practical sort would be of more use to you.

Next time you see him ask "where is the second avionic master switch ?"

Thanks for your help everyone! Handed in my completed answer sheet during the briefing before my flying lesson on Sunday to discover that my instructor Jimmy also reads pprune :O