Insights

An exercise you should try

When I ask VFR-only pilots what they do to maintain proficiency, there is never a sense of enthusiasm in their responses. I have a solution: dead-reckoning navigation. OK, I hear your responses, but they cannot be printed in this publication.

So try this one: mini-dead-reckoning navigation. That's what I call this enjoyable proficiency task, because it does not require a plotter, calculator, complicated mental computations, or electronic navigation equipment.

Why do this? Because it's one of the many parachutes that you must carry when flying--mental parachutes that give you bail-out protection when things do not go as planned. They give you an out that ensures flight safety when the unexpected occurs, and when you are flying, the unexpected is always lurking around the corner.

Use a current terminal area or sectional chart, and make a course line between two points that are least 30 to 40 miles apart. With a pen or pencil and a straight edge, such as the edge of the airplane's checklist, draw a course line. Or, you can pinch both ends of the desired course line with the thumb and index finger of each hand, pull your hands apart so that the chart is taut, and slide that portion of the chart back and forth across your chin to form a crease, which becomes the course line. Now, place a straight edge on the course line and keep it parallel to that line while you slide it over to a VOR compass rose in order to determine your no-wind magnetic heading (see "Looking for Lower," October 2005 AOPA Flight Training).

You must learn how to measure mileage with your fingers. I bend either little finger into an inverted U so that the first and third segments of the finger are parallel (the tip of the finger is touching its base). The full span of either finger's middle segment now equals five nautical miles on a terminal area chart and 10 nm on a sectional chart. If that doesn't work for you, try the middle segment of your index finger or the span of your index and middle fingers when held together and placed flat on the chart.

Return to the course line and draw a circle around prominent references that lie on or adjacent to that course. The distance between reference points should be no more than 10 nm. Use towers, major highway intersections, and geographic references.

If you want to use multiple legs and a navigation log, list only the end points of each leg. Do not list the intermediate reference points mentioned above, because those are used only for course orientation so that you can correct for wind drift and remain on course.

Mini-dead-reckoning navigation works best at altitudes that are within 2,500 feet of the ground; you're less than 3,000 feet from the surface, so altitude is not dependent on magnetic course. Before flying, however, check the airplane's magnetic compass for accuracy while taxiing parallel to and perpendicular to the departure runway.

To start the leg, note the position of the second hand on the airplane's clock or start a timer. Assume that a radio tower eight miles ahead is the first checkpoint, and your estimated ground speed is 110 kt. That's almost two miles per minute. Estimated time then is four minutes (8 divided by 2). That's not very accurate, but that's not important.

For the first three minutes, do not attempt to orient yourself by continually referencing the ground and your navigation chart. That will cause false assumptions and easily lead to disorientation. Spend that time managing your airplane, maintaining your heading, and looking for traffic.

When one minute remains, look to where the radio tower should be. You'll spot it and immediately pinpoint your position. If you're to the right or left of course, make a 90-degree turn to return to the course line, turn to a new heading that should compensate for the previous drift error, and determine the approximate time required to reach the next checkpoint.

With just a little practice, the advantage of using mini-dead-reckoning navigation will quickly become apparent. If you use the checkpoints and aggressive action to ensure that you stay on the course line, you will go where the course line goes, you'll learn that you can manage time far better than you can manage distance, and you'll spend most of your time looking outside the cockpit. Now, you can show some enthusiasm with regard to proficiency training.

Ralph Butcher, a retired United Airlines captain, is the chief flight instructor at a California flight school. He has been flying since 1959 and has 25,000 hours in fixed- and rotary-wing aircraft. Visit his Web site.