Plane & Pilot
Tuesday, March 6, 2012

How Low Should You Go?


Speed never looks so spectacular as when you’re close to the ground


First, there's always the question of engine reliability. If you're drifting along 50 feet above the most barren of deserts or the most beautiful of forests and the engine goes on strike, you won't have much time for troubleshooting and the impending emergency landing. If you fly a twin or a turboprop, your odds are slightly better, but there's still a higher element of risk than if you were traveling at 10,500 feet.

Similarly, everyone knows it's inefficient to fly low, an especially heinous offense in this day of $6/gallon avgas. Most normally aspirated piston airplanes do their best work at 7,000-9,000 feet where 75% power is all there is. If you fly behind one or more turbochargers, flying low makes even less sense unless you're skimming along above the Tibetan Plateau.

Similarly, operating in the bottom quarter-mile of sky means the ride will be rougher. The lower you fly, the greater the effect of heat and orographic turbulence. Altitude often helps immunize an aircraft from the effects of thermal and wind-induced turbulence.

But wait a minute. Some airplanes lend themselves to flying low. A J-3 Cub, an Aeronca Champ, a Porterfield, a Luscombe 8A, a Cessna 140 and a dozen other models from the same era seem to cry for low-level operation. Years ago, I picked up an American Champion Scout in Wisconsin and ferried it to Orange County, Calif. The very nature of the airplane pleaded for a low-level trip, and I obliged, flying at 500 feet most of the way, routing diagonally across the Midwest to Santa Fe, N.M., to avoid the high Rockies, then turning west over Monument Valley, Grand Canyon and on to California. Flying the Southwest's Indian country at low altitude provides a perspective you'll never see from 10,500 feet.
I learned a lot flying low: checking the wind by watching cows face out of it or looking for the lee on calm water, examining circular irrigation…
I landed at the smallest airports I could find on that trip, one of them a dirt strip in northwest New Mexico, not because there was anything interesting there, just because I could. Contrary to what you might expect, the occasional farmer or rancher we saw usually gave us a happy wave of his hat as we passed overhead.

Admittedly, some pilots do take low flying to ridiculous extremes. One P-51 pilot in Texas was chasing cows at very low altitude when he ran into a power line. The P-51 was totaled; our intrepid warbird pilot walked away.



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