C

C5Engineer

Member
I just rebuilt a non RV experimental from the ground up and I had my first conditional yesterday. I had a question I was hoping you guys could help me out with. It has a compass in it that has a flat face, similar to a gyro only it's just a mag compass that can be adjusted. The A&P checked that it swung. He also told me I needed to have a correction card for it. According to FAR's that I read a compass is not even required equipment for an Experimental that is Day VFR only BUT the operating limitations can state otherwise as always. Because of some circumstances that is a whole another story I have to re apply for my AW cert and I'm meeting with a DAR on Wed for that process. I want it to go as smoothly as possible. My field DOES NOT have a compass rose so doing up a card would kind of be a pain that I don't want to mess with if I don't have to.

Any advice on the subject so make my DAR visit go as smoothly as possible?

Quick shot of my panel to show the compass. It's in the center on top of the glare shield

Photoshoot2.jpg
 
Thanks for the link I should have searched..I'm a moderator on a large forum and know better but I only have basically one day left to do any final tweaking on my plane before the DAR comes out so I'm a getting a bit ancy.....i.e. lazy for looking for info :D After reading that thread and several others on other forums it's still grey area. I think I'll at least print one out and have it available in case he wants to see it but I'm not going to stress over having one posted and filled out.

On a side note..great forum. I've always been fascinated with RV's but unfortunately WAY out of my price range. I'm an enlisted guy in the Airforce and play money is tight sometimes. I rescued an Avid Flyer out of a barn and have been slowly rebuilding it over the past 4 years. My meeting with the DAR wed is my last step in having it legally ready to fly. What a great feeling of accomplishment!

Here's a shot of it on her first taxi in nearly 15 years

IMG_5012.jpg
 
If you have a cheap GPS..

...you can taxi a little bit on the heading you want and then look at what the compass indicates and use the GPS as your compass rose. It's what I did for my Air Tractor's correction card.

Regards,
 
When I had my DAR inspection, I saw the face of my DAR light up when he saw the Compass Correction card. "Wow - you even have one! Most people don't, and if you have a compass, you should!" When I sheepishly pointed out that it was still blank, his response was "that's OK, it just needs a card - i don't know if it's accurate!"

And neither will anyone else.....I'd do Pierre's GPS line to establish north, and fill out your card.

Paul
 
C5Engineer said:
Because of some circumstances that is a whole another story I have to re apply for my AW cert and I'm meeting with a DAR on Wed for that process. I want it to go as smoothly as possible. My field DOES NOT have a compass rose so doing up a card would kind of be a pain that I don't want to mess with if I don't have to.

Any advice on the subject so make my DAR visit go as smoothly as possible?
Click to expand...

Put the card in the plane and fill in some numbers according to best estimation (use a Boy Scout compass as a rose). How will the DAR know how accurately the card reflects the actual performance of the compass?

If you are day VFR and have a GPS you will most likely never use the vertical card compass anyway. :)

Enjoy your new plane!
 
Sam Buchanan said:
If you are day VFR and have a GPS you will most likely never use the vertical card compass anyway. :)
Click to expand...

I use it all the time! The plane is on GPS controlled auto-pilot, and I use the compass to adjust my constantly precessing six pac directional gyro. Just something to do... :)

L.Adamson --- RV6A
 
pierre smith said:
...you can taxi a little bit on the heading you want and then look at what the compass indicates and use the GPS as your compass rose. It's what I did for my Air Tractor's correction card.
Click to expand...
This procedure will work in some places, but it won't work everywhere. The GPS determines true track and current position. It then looks up the predicted magnetic variation for the current position and converts true track to magnetic track. The problem is that the GPS's internal model of magnetic variation has a fairly coarse resolution. If there are any local magnetic anomalies they won't be accounted for in the predicted magnetic variation.

Here is an example of the problem - In my day job, I see some of the in-service issues reported by operators of some aircraft types. One popular regional jet has had many reports of compass anomalies when the crew checks the heading on the runway at some airports. This aircraft has a fairly low wing, with the flux valves in the wing tips, and an Attitude and Heading Reference System that responds quite quickly to changes in the local magnetic lines of flux. It turns out that there is a lot of scrap steel in the fill that was placed below many ramps and runways, causing local magnetic anomalies, which is affecting the accuracy of the compass system of this regional jet at some airports. Other aircraft types, with flux valves higher off the ground, aren't affected nearly as much.
 
I had previously read this topic on the VAF forums...

...and my take-away was the inclusion of the compass correction card was at the "whim" of whatever DAR or FAA Airworthiness Inspector you happen to get. If the card is not present, then you may (or may not) have an issue with the inspector. If it is there, then you are covered. It does not need to be filled out, just present.
 
Great discussion. I got tired of all the speculation so I just called the DAR that will be inspecting my plane and asked him. He said do you know the equipment requirements for an experimental? I said yes I do I looked them up and he said then you know you don't even need a compass let alone a card. Guess that answers it at least for me. As you guys know every A&P and every DAR is different. Thanks for help.
 
Kevin Horton said:
It turns out that there is a lot of scrap steel in the fill that was placed below many ramps and runways, causing local magnetic anomalies...
Click to expand...

I'd be more concerned about the scrap steel that's flying around with you! :D

Seriously, airborne and a failed GPS isn't the time to discover your airframe needs de-gaussing! :eek:
 
I had to replace my compass in my C-152 right befor my PP check ride. My CFI also is an AP/AI and runs a shop on the field. He told me that the particular examiner will want a CC card plainly visable on the IP. We also do not have a compass rose on our field to set it and this is how he told me to do it. Our taxi-way runs parrallel to our runway. You could use the runway if you have to: Taxi straight and center on the taxi-way. Stop and let the compass stop. Set the DG to runway heading. Turn around and do it again in the opposite direction. If you did it right, the DG heading will be right. You can then head out to the ramp and start adjusting and recording compass correction using the DG as the compass rose. I am sure that some will find this method unacceptable, but he's been around forever and this is how he does it. I did it and a year later, my compass http://www.sirs.co.uk/aircraft light.htm#Navigator and the correction card is right on. As a side note, I absolutely love this compass and will put one of these in my -10. When we built the Cozy MKIV, we never installed a manual compass but did have a compass correction card pasted on the IP based on the BM EFIS that was adjusted and set on the compass rose the field we finished building on had.
 
David Clifford said:
I had to replace my compass in my C-152 right befor my PP check ride. My CFI also is an AP/AI and runs a shop on the field. He told me that the particular examiner will want a CC card plainly visable on the IP. We also do not have a compass rose on our field to set it and this is how he told me to do it. Our taxi-way runs parrallel to our runway. You could use the runway if you have to: Taxi straight and center on the taxi-way. Stop and let the compass stop. Set the DG to runway heading. Turn around and do it again in the opposite direction. If you did it right, the DG heading will be right. You can then head out to the ramp and start adjusting and recording compass correction using the DG as the compass rose. I am sure that some will find this method unacceptable, but he's been around forever and this is how he does it. I did it and a year later, my compass http://www.sirs.co.uk/aircraft light.htm#Navigator and the correction card is right on.
Click to expand...
This method can get you close. However, you must know your runway heading. The numbers painted on the runway can be several degrees off for 2 reasons. One, they are rounded off to the nearest 10 degrees, and two, if they were painted some time ago, the magnetic direction has probably shifted since then.
 
Going to Airnav.com...

Mel said:
This method can get you close. However, you must know your runway heading. The numbers painted on the runway can be several degrees off for 2 reasons. One, they are rounded off to the nearest 10 degrees, and two, if they were painted some time ago, the magnetic direction has probably shifted since then.
Click to expand...

...will give the exact runway heading in both magnetic and true bearings...:)

Example....

http://www.airnav.com/airport/U02
 
We have intersecting runways on our field so I taxied to the both thresholds and then did the 180 thing and tweaked the compass with a brass screwdriver. I'm within 5 degrees on all 4 runways. Much closer than that and I think your guessing at that point. Thanks for all the info.
 
FAA Input on Compass Card Requirement...

Here is a response from a Fed who writes these regulations in DC:


You can find the requirement for a compass (magnetic direction indicator)
at Title 14 of the Code of Federal Regulations (14 CFR) section 91.205
(b)(3).

BTW, you can find the latest regulations at: http://ecfr.gpoaccess.gov/

Go to Title 14 and you can figure out the rest.

14 CFR ? 91.205 Powered civil aircraft with standard category U.S.
airworthiness certificates: Instrument and equipment requirements.

(a) General. Except as provided in paragraphs (c)(3) and (e) of this
section, no person may operate a powered civil aircraft with a
standard category U.S. airworthiness certificate in any operation
described in paragraphs (b) through (f) of this section unless that
aircraft contains the instruments and equipment specified in those
paragraphs (or FAA-approved equivalents) for that type of operation,
and those instruments and items of equipment are in operable
condition.

(b) Visual-flight rules (day). For VFR flight during the day,
the following instruments and equipment are required:

(3) Magnetic direction indicator.

Now if you go to the type certification rules (airworthiness requirements)
to 14 CFR 23.1547 and 25.1547, you will find the requirement for a compass,
complete with compass card, or placard as the regulations call it.

14 CFR ? 23.1547 Magnetic direction indicator.

(a) A placard meeting the requirements of this section must be
installed on or near the magnetic direction indicator.
(b) The placard must show the calibration of the instrument in level
flight with the engines operating.

(c) The placard must state whether the calibration was made with
radio receivers on or off.

(d) Each calibration reading must be in terms of magnetic headings in
not more than 30 degree increments.

(e) If a magnetic nonstabilized direction indicator can have a
deviation of more than 10 degrees caused by the operation of
electrical equipment, the placard must state which electrical loads,
or combination of loads, would cause a deviation of more than 10
degrees when turned on.

So the type certification requirements require a compass card for
airworthiness certification. So unless the aircraft is properly altered
with something other than a magnetic direction indicator, a compass card is
required for a aircraft with a standard category certificate of
airworthiness.

TSO C7e for non stabilized magnetic direction indicators also figures in
there also. The manufacturer?s technical documents will usually indicate
that the compass card is part of the magnetic direction indicator system.

Now looking at homebuilt/experimental is quite another matter. These
aircraft are outside the scope of ? 91.205 as well as the type
certification rules, however, if the aircraft with an experimental
certificate has previously held a standard category certificate of
airworthiness, then those requirements still apply unless otherwise
modified by the experimental nature of the aircraft.

Homebuilts can have just about anything the builder wants.

Both aircraft having a special certificate of airworthiness in the
experimental classification and homebuilts come under the operating
limitations outlined at 14 CFR ? 91.319 which, among a plethora of other
restrictions, restrict those aircraft to VFR day only.

However, after all of that, there is no regulation that would prevent an
operator from accomplishing a compass calibration procedure and installing
a compass deviation placard when the regulations do not otherwise require
one.

Anyway, hope this helps

Best Regards

Russ

Russell S. Unangst, Jr.
Technical Advisor, Airworthiness
FAA Headquarters/Flight Standards Service, AFS-305
5th Fl, 950 L'Enfant Plaza, SW
Washington, DC 20024

202-385-6440 202-385-6440
__________________
 
DAGO said:
Here is a response from a Fed who writes these regulations in DC:


You can find the requirement for a compass (magnetic direction indicator)
at Title 14 of the Code of Federal Regulations (14 CFR) section 91.205
(b)(3).

BTW, you can find the latest regulations at: http://ecfr.gpoaccess.gov/

Go to Title 14 and you can figure out the rest.

14 CFR ? 91.205 Powered civil aircraft with standard category U.S.
airworthiness certificates: Instrument and equipment requirements.

(a) General. Except as provided in paragraphs (c)(3) and (e) of this
section, no person may operate a powered civil aircraft with a
standard category U.S. airworthiness certificate in any operation
described in paragraphs (b) through (f) of this section unless that
aircraft contains the instruments and equipment specified in those
paragraphs (or FAA-approved equivalents) for that type of operation,
and those instruments and items of equipment are in operable
condition.

(b) Visual-flight rules (day). For VFR flight during the day,
the following instruments and equipment are required:

(3) Magnetic direction indicator.

Now if you go to the type certification rules (airworthiness requirements)
to 14 CFR 23.1547 and 25.1547, you will find the requirement for a compass,
complete with compass card, or placard as the regulations call it.

14 CFR ? 23.1547 Magnetic direction indicator.

(a) A placard meeting the requirements of this section must be
installed on or near the magnetic direction indicator.
(b) The placard must show the calibration of the instrument in level
flight with the engines operating.

(c) The placard must state whether the calibration was made with
radio receivers on or off.

(d) Each calibration reading must be in terms of magnetic headings in
not more than 30 degree increments.

(e) If a magnetic nonstabilized direction indicator can have a
deviation of more than 10 degrees caused by the operation of
electrical equipment, the placard must state which electrical loads,
or combination of loads, would cause a deviation of more than 10
degrees when turned on.

So the type certification requirements require a compass card for
airworthiness certification. So unless the aircraft is properly altered
with something other than a magnetic direction indicator, a compass card is
required for a aircraft with a standard category certificate of
airworthiness.

TSO C7e for non stabilized magnetic direction indicators also figures in
there also. The manufacturer?s technical documents will usually indicate
that the compass card is part of the magnetic direction indicator system.

Now looking at homebuilt/experimental is quite another matter. These
aircraft are outside the scope of ? 91.205 as well as the type
certification rules, however, if the aircraft with an experimental
certificate has previously held a standard category certificate of
airworthiness, then those requirements still apply unless otherwise
modified by the experimental nature of the aircraft.

Homebuilts can have just about anything the builder wants.

Both aircraft having a special certificate of airworthiness in the
experimental classification and homebuilts come under the operating
limitations outlined at 14 CFR ? 91.319 which, among a plethora of other
restrictions, restrict those aircraft to VFR day only.

However, after all of that, there is no regulation that would prevent an
operator from accomplishing a compass calibration procedure and installing
a compass deviation placard when the regulations do not otherwise require
one.

Anyway, hope this helps

Best Regards

Russ

Russell S. Unangst, Jr.
Technical Advisor, Airworthiness
FAA Headquarters/Flight Standards Service, AFS-305
5th Fl, 950 L'Enfant Plaza, SW
Washington, DC 20024

202-385-6440 202-385-6440
__________________
Click to expand...

Please note the following quote from the above regs:

"14 CFR ? 91.205 Powered civil aircraft with standard category U.S.
airworthiness certificates: Instrument and equipment requirements."

We do not fly "standard category" aircraft so 91.205 is not applicable to aircraft with experimental airworthiness certificates.

However.......the flight limitations that are issued when we get our experimental airworthiness certificate refers us back to 91.205 if the aircraft is going to be operated during night VFR or IFR flights. Please note that this does not include an obligation to meet 91.205 for day VFR flights. There are no regs regarding flight instruments for experimental aircraft in day VFR conditions.

Prudence and common sense may dictate otherwise, however.
 
It's an operational issue.

C5Engineer said:
I was issued my AW cert by a DAR today and no questions were asked about my card.
Click to expand...
Your DAR certificated your aircraft for day VFR operations.
If you decide to operate your aircraft in IMC or at night per your operating limitations, it's up to you to show that it complies with 91.205.
 
This was covered in an earlier thread, but I'll cover it here again. 91.205 does contain the requirement for a "magnetic direction indicator", so if you want to operate your homebuilt at night or under IFR (as allowed by the operating limitations) you'll need a "magnetic direction indicator". 91.205 does not, however, contain any requirement for a correction card of any kind. Requirements for correction cards can be found in CAR 3, CAR 4, and FAR part 23 (as well as other regulations pertaining to aircraft with standard airworthiness certificates) but none of these regulations apply to the certification of an experimental amateur-built aircraft. Thus, there is no specific regulatory requirement for a compass correction card in an amateur-built certification. Any inspector who attempts to withhold your airworthiness certificate based on the absence of a compass correction card is not doing so under any specific regulation. Now, the inspector may feel in his/her personal opinion that an airplane with no compass and no card is not in a "condition for safe operation", but this is strictly opinion and not based on applicable regulations.

Cheers!

Joe
 
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