AOPA Pilot Magazine - May 2013 - 18

PROFICIENT PILOT

Time to be true?

BY BARRY SCHIFF

There is nothing sacred or indispensable any more

BARRY SCHIFF

has written
more than 1,600
magazine articles
and currently is
writing his
fourteenth book.

18 | AOPA PILOT May 2013

WHEN I USED TO FLY TWA’s polar routes in Boeing 707s
between the U.S. West Coast and northern Europe, we
often passed close to the magnetic north pole. We had
to use gyroscopic polar-path compasses with predictable rates of precession to maintain desired headings.
This is because conventional magnetic compasses are
utterly useless when within about 600 miles of the magnetic pole. They dip, wander, and point confusingly in
one direction when they should point in another.
In those days, the airport at Resolute Bay in Canada’s
far north archipelago was close to the magnetic pole.
I used to think about how much fun it would be to fly
there in a light airplane and make a more detailed study
of compass behavior.
Today, though, the magnetic pole is nowhere near
Resolute Bay. Incessantly in slow motion, it is now
moving northwesterly over the Arctic Ocean at about
37 miles per year, faster than ever previously noted.
Continuing at this speed and direction, the pole will
reach Russia near the end of the century. Some experts
predict it might shift southwest toward Mongolia.
This movement of the magnetic north pole creates
problems for aviation by causing magnetic variation
(sometimes called magnetic declination) to change
everywhere on Earth. Lines of equal magnetic variation (isogonic lines) have to be periodically redrawn on
aeronautical charts, magnetic-course directions have to
be changed, and runways have to be renumbered and
repainted. (This also causes problems for migrating
birds that sense and utilize the Earth’s lines of magnetic flux for navigation.)
As a result of this movement of the magnetic north
pole, there is quietly developing an undercurrent of sentiment suggesting that the time might be approaching
to shift away from the use of magnetic directions and
toward navigation by reference to the true north pole,
the position of which obviously does not change. It is
argued that such “true” navigation would be simpler,
more logical, more intuitive, and made possible by the
proliferation of satellite navigation. Global positioning systems can easily display true directions. Runway
numbers would become permanent and not subject to
the Earth’s shifting magnetic field. So, too, would true
courses shown on aeronautical charts become permanent. Modern electronics can easily convert the
magnetic heading of an aircraft to a display of true
direction.

Gone would be the need for those mnemonic ditties, True Virgins Make Dull Company, Can Ducks Make
Vertical Turns, and East is Least; West is Best.
Would an industry-wide transition from the use of
magnetic to true direction force those of us flying older
aircraft with steam gauges to equip our antique aircraft with GPS and electronic displays? No. We could
continue to entertain ourselves with a dancing whiskey compass and navigate much the way we do now.
Those wanting or needing to fly IFR with traditional
instrumentation likely would have to bite the bullet and
reequip their aircraft to comply with the needs of nextgeneration airspace, a future requirement (ADS-B).
Flying with only a wet compass would, however,
require a mental adjustment when in the traffic pattern. When landing on a runway with a true direction of
220 degrees (Runway 22T?), pilots with only traditional
instrumentation would have to anticipate a magnetic
direction of 240 degrees, for example, when lined up
on the runway or on final approach.
Think all of this is far-fetched? Think again. The
days of the whiskey compass may already be numbered.
In what may seem like a blasphemous omission, standard equipment on the Cessna 162 Skycatcher does not
include a conventional magnetic compass. There apparently is nothing sacred or indispensable anymore.
If aviation does transition to the use of true directions, it might then become time to make a few other
adjustments. How about substituting a 400-degree
circle for the 360-degree circle? Just think how much
easier this would make navigation. Reciprocal directions
would be a snap. Just add or subtract 200 degrees. A
quarter-turn circle would be 100 degrees, a three-quarter-turn circle would be 300 degrees, and so forth.
While we’re at it, how about instituting the 28-day
month? The 1st, 8th, 15th, and 22nd of every month
would be a Sunday, and so forth. Gone forever would be
the need to consult a calendar to determine what day of
the week is a given date. This would result in a 13-month
year, which might be awkward. Another minor problem would be the extra, 365th day of the year. But it
wouldn’t have to have a date. We could just call it New
Year’s Day, or Aviation Day, or some such thing. And
then, of course, there is the metric system of measurement. Hmm. I don’t think I’ll go there.
AOPA
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AOPA Pilot Magazine - May 2013

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