Proficient Pilot: Time to be true?

There is nothing sacred or indispensable any more

May 1, 2013

Barry Schiff

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 next-generation 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.

Barry Schiff has written more than 1,600 magazine articles and currently is writing his fourteenth book. Visit the author’s website.