Math Myths


Usually the AOPA magazine migrates to my side of the bed where it languishes in the dust until recycling day. Lately I’ve had time to peruse the glossy and one item in particular caught my attention. ‘Math Myths’ by Bruce Landsberg, president of AOPA Foundation has great, basic, numbers we can retain. Math was always my weakest arena and his words resonate. I’ve cut and stitched so if you’d like to read the entire article it’s in the January 2011 AOPA, page 30. These winter months are a great time to dust off the POH and tweak the memory banks.

Math Myths

There is a myth among many in aviation and education that advanced math is essential to fly with any degree of safety and skill. Unfortunately my father did not pass along his genetic gift for advanced mathematics, but that was little detriment to my becoming a pilot. With the basics of addition, subtraction, multiplication and division, safe flight operation is well within the grasp of math illiterates.

Pilots do need basic math for practical estimates and to read charts and graphs – all within the capability of liberal arts majors. When should we begin descent from cruise flight? In a piston-engine aircraft where cooling is a consideration, use five miles per thousand feet. To descend 7,000 feet to the airport, start down about 35 miles out.

Taking the Naval Aviators percentage, if the landing distance based on the POH (the best the manufacturer’s test pilot can do on a good day with a new aircraft) is 2,000 feet over a 50-foot obstacle and you’re having a bad day by being a bit fast, 2,400 feet is the approximation. From an operational perspective, the Air Safety Institute recommends adding 50 percent to the POH number, so that works out to 3,000 feet. It provides some margin for runway slope, some clearance over a taller obstacle and less than perfect technique.

Climb gradient per nautical mile is required for many departures. The standard gradient is 200 feet per nautical mile. If the ground speed is 120knots, that’s two nautical miles per minute. Two hundred times two means 400 fpm is needed to comply with the gradient. Tailwind? Be a bit more conservative. Headwind? Fat city!

For pilots it’s important to know that with 24 gallons of fuel on board and a fuel burn of eight gallons an hour, about 3 hours after takeoff a collision is a distinct possibility. There are still about two fuel mismanagement accidents weekly, so the basic math bone isn’t working for some pilots- or maybe it has nothing to do with math at all.

Basic math used in conjunction with conceptual understanding will keep one alive much longer than computational algebra. As we rebuild the pilot population there’s no need to throw up a high math barrier to aspiring pilots.

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