Compass correction card

[DannyDot]

My plane doesn't have a compass correction card, but I need one.

Based on looking at landmarks (e.g. roads) it looks like I need to fly 150 on the compass to go South and 030 to go North. Do others have this much of a correction?

On testing the compass on the ground, do I need to have the tail raised when looking at the indicated heading?

How about using the adjustments screws on the compass? Does anyone have a procedure on how to do this properly?

Danny Deger

[astjp2]

Re: Compass correction card

Danny you should ask your local avionics shop about how to adjust your specific compass.
Reading this might also help.

http://www.tpub.com/content/aviationmaintandmisc/TM-1-1500-204-23-4/css/TM-1-1500-204-23-4_70.htm

http://www.allstar.fiu.edu/aero/MagComp.htm

Tim

[Forrest Barber]

Re: Compass correction card

Here at the factory in the past we did an airborne calibration on the true section lines. Simple procedure of spliting the difference, however check your fuselage tubing first, you may need to be de -gaused ( sp) .

[Guest]

Re: Compass correction card

My plane doesn't have a compass correction card, but I need one.

Based on looking at landmarks (e.g. roads) it looks like I need to fly 150 on the compass to go South and 030 to go North. Do others have this much of a correction?

On testing the compass on the ground, do I need to have the tail raised when looking at the indicated heading?

How about using the adjustments screws on the compass? Does anyone have a procedure on how to do this properly?

Danny Deger

AC43.13-1B section 12-37 describes the process


Also, hate to burst your bubble but unless you hold an airframe mechanics certificate you can't do it. Get your A&P to work with you. See preventative maint. list below

WHAT IS PREVENTITIVE MAINTENANCE? (I recall mfgs maintenance manual may add or subtract items from the list)

from 43 appendix A

(c) Preventive maintenance. Preventive maintenance is limited to the following work, provided it does not involve complex assembly operations:

(1) Removal, installation, and repair of landing gear tires.

(2) Replacing elastic shock absorber cords on landing gear.

(3) Servicing landing gear shock struts by adding oil, air, or both.

(4) Servicing landing gear wheel bearings, such as cleaning and greasing.

(5) Replacing defective safety wiring or cotter keys.

(6) Lubrication not requiring disassembly other than removal of nonstructural items such as cover plates, cowlings, and fairings.

(7) Making simple fabric patches not requiring rib stitching or the removal of structural parts or control surfaces. In the case of balloons, the making of small fabric repairs to envelopes (as defined in, and in accordance with, the balloon manufacturers' instructions) not requiring load tape repair or replacement.

(8) Replenishing hydraulic fluid in the hydraulic reservoir.

(9) Refinishing decorative coating of fuselage, balloon baskets, wings tail group surfaces (excluding balanced control surfaces), fairings, cowlings, landing gear, cabin, or cockpit interior when removal or disassembly of any primary structure or operating system is not required.

(10) Applying preservative or protective material to components where no disassembly of any primary structure or operating system is involved and where such coating is not prohibited or is not contrary to good practices.

(11) Repairing upholstery and decorative furnishings of the cabin, cockpit, or balloon basket interior when the repairing does not require disassembly of any primary structure or operating system or interfere with an operating system or affect the primary structure of the aircraft.

(12) Making small simple repairs to fairings, nonstructural cover plates, cowlings, and small patches and reinforcements not changing the contour so as to interfere with proper air flow.

(13) Replacing side windows where that work does not interfere with the structure or any operating system such as controls, electrical equipment, etc.

(14) Replacing safety belts.

(15) Replacing seats or seat parts with replacement parts approved for the aircraft, not involving disassembly of any primary structure or operating system.

(16) Trouble shooting and repairing broken circuits in landing light wiring circuits.

(17) Replacing bulbs, reflectors, and lenses of position and landing lights.

(18) Replacing wheels and skis where no weight and balance computation is involved.

(19) Replacing any cowling not requiring removal of the propeller or disconnection of flight controls.

(20) Replacing or cleaning spark plugs and setting of spark plug gap clearance.

(21) Replacing any hose connection except hydraulic connections.

(22) Replacing prefabricated fuel lines.

(23) Cleaning or replacing fuel and oil strainers or filter elements.

(24) Replacing and servicing batteries.

(25) Cleaning of balloon burner pilot and main nozzles in accordance with the balloon manufacturer's instructions.

(26) Replacement or adjustment of nonstructural standard fasteners incidental to operations.

(27) The interchange of balloon baskets and burners on envelopes when the basket or burner is designated as interchangeable in the balloon type certificate data and the baskets and burners are specifically designed for quick removal and installation.

(28) The installations of anti-misfueling devices to reduce the diameter of fuel tank filler openings provided the specific device has been made a part of the aircraft type certificiate data by the aircraft manufacturer, the aircraft manufacturer has provided FAA-approved instructions for installation of the specific device, and installation does not involve the disassembly of the existing tank filler opening.

(29) Removing, checking, and replacing magnetic chip detectors.

(30) The inspection and maintenance tasks prescribed and specifically identified as preventive maintenance in a primary category aircraft type certificate or supplemental type certificate holder's approved special inspection and preventive maintenance program when accomplished on a primary category aircraft provided:

(i) They are performed by the holder of at least a private pilot certificate issued under part 61 who is the registered owner (including co-owners) of the affected aircraft and who holds a certificate of competency for the affected aircraft (1) issued by a school approved under §147.21(e) of this chapter; (2) issued by the holder of the production certificate for that primary category aircraft that has a special training program approved under §21.24 of this subchapter; or (3) issued by another entity that has a course approved by the Administrator; and

(ii) The inspections and maintenance tasks are performed in accordance with instructions contained by the special inspection and preventive maintenance program approved as part of the aircraft's type design or supplemental type design.

(31) Removing and replacing self-contained, front instrument panel-mounted navigation and communication devices that employ tray-mounted connectors that connect the unit when the unit is installed into the instrument panel, (excluding automatic flight control systems, transponders, and microwave frequency distance measuring equipment (DME)). The approved unit must be designed to be readily and repeatedly removed and replaced, and pertinent instructions must be provided. Prior to the unit's intended use, and operational check must be performed in accordance with the applicable sections of part 91 of this chapter.

(32) Updating self-contained, front instrument panel-mounted Air Traffic Control (ATC) navigational software data bases (excluding those of automatic flight control systems, transponders, and microwave frequency distance measuring equipment (DME)) provided no disassembly of the unit is required and pertinent instructions are provided. Prior to the unit's intended use, an operational check must be performed in accordance with applicable sections of part 91 of this chapter.

[DanBrown]

Re: Compass correction card

Please correct me, but I don't see that swinging the compass and updating the correction card is a maintenance item. In the past, I thought of this as an operational item that the pilot can do and note in the aircraft log. Some airports have a compass rose on the ground to facilitate this. I do seem to recall that there is a limit on the amount of error that is allowed on the correction card -- it seems to me that 20 degrees is too much -- compass is bad, in a poor location, out of adjustment or there is too much stay magnetic fields.

[Guest]

Re: Compass correction card

Please correct me, but I don't see that swinging the compass and updating the correction card is a maintenance item. In the past, I thought of this as an operational item that the pilot can do and note in the aircraft log. Some airports have a compass rose on the ground to facilitate this. I do seem to recall that there is a limit on the amount of error that is allowed on the correction card -- it seems to me that 20 degrees is too much -- compass is bad, in a poor location, out of adjustment or there is too much stay magnetic fields.

The process specifies adjusting the compass.

If one adjusts the compass as indicated in the process then it is certainly maintenance and is not preventive maintenance because its not on the list.

If you don't make the adjustment then it not maintenance at all, no arg there.

I honestly can't tell what it is if you make out a swing card and put it in the plane. I suspect its a problem if you're not a mechanic.

Owners should give a careful read to part 43 & 91K, maybe part 65.

Dave

[lfries]

Re: Compass correction card

In Calif. my county, the roads are generally laid out in "True" and not Magnetic. Variation is 14 or 15 deg. east here. On a sectional look at the VOR compass rose North then compare with the Line of Long. which goes to true north and south. When I tell my students to find the airport without the use of electronic aids they knowto follow the section line or road in a east, west, north, or south direction as the compass will indicate around 15 degrees less than the true direction.

[Forrest Barber]

Re: Compass correction card

yep and here in Ohio it is 7 degrees E . We always did an airborne check with radio on then off....

[DannyDot]

Re: Compass correction card

[QUOTE=lfries;33583]In Calif. my county, the roads are generally laid out in "True" and not Magnetic. Variation is 14 or 15 deg. east here. On a sectional look at the VOR compass rose North then compare with the Line of Long. which goes to true north and south. When I tell my students to find the airport without the use of electronic aids they knowto follow the section line or road in a east, west, north, or south direction as the compass will indicate around 15 degrees less than the true direction.[/QUOTE

Road headings down here south of Houston are laid out every which direction. I have found an A&P familiar with compass adjustments I am going to work with.

Danny Deger

[flyguy]

Re: Compass correction card

Checked the first reference above and noticed there seems to be two errors in the DEV column example. Am I missing something, or is that so?
DC

[O.Taylor]

Re: Compass correction card

Here at the factory in the past we did an airborne calibration on the true section lines. Simple procedure of spliting the difference, however check your fuselage tubing first, you may need to be de -gaused ( sp) .

should Danny be de-gaussed or the airframe??, OH, IAM sorry, it's late

[DannyDot]

Re: Compass correction card

should Danny be de-gaussed or the airframe??, OH, IAM sorry, it's late

I have been de-loused before, but never de-gaussed :-)

Danny Deger

[cpirrmann]

Re: Compass correction card

Just don't agree to the wax job.

[Forrest Barber]

Re: Compass correction card

It is raining, my hard drive crashed at the airport, the struts on X-Ray did not work out, the PTO shaft that snapped on the big tractor got delayed in shipment, our cat had three kittens, neighbors dog tried to bite me as a was doing them a favor, and then I log on to this thread.... BLESS U ALL , there is hope for this world with a wee bit of humor.
Back later with good news I hope!!

[DannyDot]

Re: Compass correction card

Danny you should ask your local avionics shop about how to adjust your specific compass.
Reading this might also help.

http://www.tpub.com/content/aviationmaintandmisc/TM-1-1500-204-23-4/css/TM-1-1500-204-23-4_70.htm

http://www.allstar.fiu.edu/aero/MagComp.htm

Tim

I found a good link on how to do the correction. While the engine is running and radios on, correct heading north by facing north an using the little correction screw. I my case I had about a 30 degree error for north. Then turn to south and take out half the correction. Repeat for east/west.

I didn't have a correciton rose on the airport, so I used my boy scout compass.

I haven't tried it airborne yet, but I think I will be much improved.

Danny Deger