CAA: GA News, "Ever wonder who paints those compass roses?"

["Stephen Irwin" <stepheni@cwnet.com>]

Friday, May 12, 2000

Ever wonder who paints those compass roses?
GA News


“Is that the right airport?”

How many times have you asked yourself that as you wrestle with a sectional
while on a cross-country? Before the days of radio navigation, VORs and GPS,
pilots asked that question a lot. To help those lost souls find their way,
the process of “air marking” was developed. Air marking is basically
painting a sign on the ground or on a roof or on a water tower to provide
direction to pilots.

During the 1930s The Ninety-Nines, with the blessing of the Civil Aviation
Administration (the precursor of the FAA) painted navigation signs on
rooftops every few miles. At airports, the name of the field or a compass
rose was painted to help pilots find their way. The marks on houses were
painted roughly every five miles.

Before World War II, when radio navigation was in its infancy, pilotage and
dead reckoning were the only means pilots had for getting from Point A to
Point B. A symbol like 06 with an arrow pointing in a direction meant “6
miles to the airport”. The directional paint jobs did not last long; they
were covered up during WWII so they wouldn’t help an airborne enemy find
their target.

After the war, The Ninety-Nines continued their campaign to air mark the
country. Despite all of the advances in navigation, air marking is still an
important part of navigation and airport identification.

Air marking is taking place all over the country. In Southern California, a
Ninety-Nine chapter has plans to paint a compass rose at John Wayne
Airport-Orange County (SNA).

Ninety-Nines member Vicki Anderson, who also happens to be a systems analyst
for the airport, said the project grew out of a realignment of a taxiway and
the need for a landmark.

“At John Wayne Airport you share the taxiways with 757s,” Anderson said.
“Often the tower tells you to hold short at midfield. For a pilot who is
just visiting and doesn’t know the field, that can be confusing.”

Anderson said the new compass rose will be painted on the taxiway so pilots
can be told “hold short on the compass rose.”

Compass roses need to be repainted every few years. In addition to wear and
tear, compass roses are subject to magnetic variation as the earth’s
magnetic fields change over time. A compass rose painted 25 years ago may
show magnetic north in a different location than one painted today. Because
of this variation, before painting begins, a professional survey is done to
determine where magnetic north is. Once that is done and airport officials
have given permission, the design work can begin.

The Ninety-Nines have an air marking manual that contains strict guidelines.
For example, the compass rose must be located in a non-traffic area (The one
at John Wayne Airport will be painted in a run-up area between two runways).
The manual also contains information on size and layout of a compass rose,
but sometimes The Ninety-Nines have to reduce the pattern to fit their
location.

“Ours (at John Wayne Airport) uses a 50-foot radius,” Anderson said. “The
pattern we got from The Ninety-Nines manual is calculated on an 80-foot
radius. There are a couple of different designs we can use. What matters
most is that when you align the airplane on magnetic north you can make a
compass correction card based on that.”

There is a caveat in the project: Although The Ninety-Nines paint the
compass rose, they cannot be held responsible for any compass deviation.

“The people who do the survey are responsible for any deviation,” Anderson
said.

The creation of a compass rose begins with a chalk outline based on the
surveyor’s determination of magnetic north. Using string to keep the lines
straight, the compass outline is drawn, then painted. Two different types of
paint can be used for the project: highway paint or water-based latex. Since
white and blue are the standard colors for The Ninety-Nines, that’s what
many of the compass roses are done in.

To get more info about air marking, contact Ellen Nobbles-Harris, The
Ninety-Nines international air-marking chairwoman, at 856-224-4484 or by
E-mail at Nobles-HarrisE@valero.com .


   Post your opinion on this story in the CAA General Aviation Forum
http://www.californiaaviation.org/cgi-bin/dcforum/dcboard.cgi?conf=DCConfID2

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