Air Marking

Today, Ninety-Nines carry on the tradition and fulfill the need for airmarkings by volunteering their time to paint the airport names, compass rose symbols and other identifications on airports.  Compass roses are used at airports for swinging airplane compasses (calibrating with true magnetic headings and reducing compass errors.) Our chapter uses the basic design of the compass rose prepared by the Air Marking Chairman of the North-Central Section of the 99s, revised March, 1988, from a design made earlier by the Three Rivers Chapter.A compass rose The Scioto Valley Chapter modified the procedure of the layout, but kept the design itself nearly unchanged. We made some minor adjustments in the logo of the interlocking nines for a more accurate rendition of the official logo, and re-depicted the logo within a rectangular grid centered on the origin of the compass rose. Also, we request the surveyor to mark magnetic directions every 30 degrees around the circle, eliminating some difficult geometrical constructions that were required when only the North line was surveyed. We have used these procedures since 1990, and have been quite successful in producing very striking compass roses at numerous airports in central Ohio, New Mexico, and Colorado.  Click here for instructions on producing the compass rose. Here is a list of the Scioto Valley Compass Rose projects to date:  
Date Location


September 15, 1990 Fayette County, OH I23
September 7, 1991 Coshocton County, OH I40
June 20, 1992 Union County, OH KMRT
July 15, 1995 Coshocton County, OH I40
June 29, 1996 Holmes County, OH 10G
September 27, 1997 Madison County, OH KUYF
June 5, 1999 Delaware Municipal, OH KDLZ
October 19, 2001 Raton Municipal, NM KRTN
September 25, 2002 Cañon City, CO KCNE
October 11, 2003 Greene County, OH I19
June 5, 2004 Delaware Municipal, OH KDLZ
August 13, 2005 Darby Dan (Columbus), OH 75OA
May 19, 2007 Delaware Municipal, OH KDLZ
October 28, 2007 Union County, OH KMRT
July 19, 2008 Delaware Municipal, OH KDLZ
May 12, 2012 Madison County, OH KUYF
October 13, 2012 Raton Municipal, NM KRTN
May 11, 2014 Delaware Municipal, OH KDLZ
May 7, 2017 Union County, OH KMRT
Photos from Delaware Municipal - 2014  

How to Know When Your Compass Needs Adjustment

Compass Compensator Magnets

For airworthiness, the FAA requires that your magnetic compass must show no greater than ±10° error for any magnetic heading. Aviation compasses are equipped with internal compensating magnets that can be adjusted to cancel out compass disturbances for most of the residual magnetism of your aircraft’s iron and steel components, such as engines, landing gear, hinges, and fasteners, thus improving the accuracy of your compass readings, usually well within the FAA limits. One of the compensating magnets, labeled N-S, trims error from the north- and south readings. The other compensating magnet, labeled E-W, trims error from the east- and west readings. Together, those two adjustments at right angles to each other can approximately neutralize the local horizontal component of your residual airframe magnetization oriented at any bearing angle relative to the longitudinal axis of the airplane.

Compass-Rose Check

With engine(s) running, battery fully charged, and avionics turned on, align your airplane with a compass rose and record your compass readings for known magnetic headings of North, South, East, and West. Separately examine the two compass readings for your North and South headings, and your other two compass readings for your East and West headings. If both the North and South readings deviate to the same side (i.e. either both a little westerly or both a little easterly), then the north-seeking pole of your compass needle is being attracted slightly toward one wing or the other, and the N-S compensator could reduce that error. By similar reasoning, if both the East and West readings deviate to the same side (i.e. either both a little northerly or both a little southerly), then the north-seeking pole of your compass needle is being attracted slightly toward your airplane’s nose or tail, and the E-W compensator could reduce that error. Contact your aircraft or avionics maintenance technician to complete the compass compensation procedure. Otherwise finish the full compass swing for readings every 30° around the circle, and prepare an updated compass-calibration card, if needed. Your gyroscopic Heading Indicator can be very useful throughout this process. Set your H.I. accurately to the magnetic heading of your first alignment over the compass rose, then use it to help you align your aircraft to all subsequent headings.