The first was when I was 17, working on my commercial pilot certificate. I was coming into a nontowered field for some landing practice and had my ears tuned to the traffic frequency inbound. Then, I made my 10-mile-out call, my 45-to-the-downwind call, and my downwind entry call.

Three seconds after my last transmission, another pilot made the exact same call. I frantically scanned for the traffic. I called the other pilot, and then, I saw his airplane’s shadow on my airplane’s nose. I chopped power. As the other airplane slid over my windshield I could see every speck of dirt on its belly. It was close enough that if I’d been in an open cockpit I could have checked the tire pressure.

The second time was just the other day when a pilot announced he was approximately ten-point-one miles northwest, inbound for landing. OK, I grant you, that’s hardly as big a deal as almost killing me. I guess with old age I’ve become less tolerant.

But my point is: Don’t let digital information make you dumb. First, there’s nothing approximate about a tenth of a nautical mile. That’s a very accurate measure of distance. To be precise, it’s 608 feet. Well, 607.61 feet for you decimal lovers. But more importantly, a decimal mile is sufficiently accurate that it’s completely inaccurate for aviation. Consider this: In a training airplane pouring on the coal at 100 knots, you’ll cross that decimal mile before you can finish your radio call, because you’re traveling “approximately” 168.78 feet per second—blowing through your tenth of a knot in less than four seconds.

Hopefully, by now you’re getting the idea. But just to be sure: Don’t use decimal points. At least not in your radio transmissions when reporting your distance. At airplane speeds, not only is decimal accuracy fundamentally inaccurate, it takes other pilots longer to mentally process a decimal number, which gives them headaches and makes them cranky. Not to mention it makes you sound like a fool. Adding, “approximately” to a decimal distance just compounds the sin.

So, keep it simple. Round up or down, and just tell me you’re approximately 10 miles out—and I’ll be happy.