by Jim Cavanagh

Aircraft performance—cruise speed, climb rate, payload, fuel consumption, range, roll weight, stall speed—is always in the grip of one harsh and unyielding constant: weight. A heavy car may be a good thing if it smoothes road response but a heavy airplane is never good. Designers sweat bullets to reduce empty weight, nipping ounces here and there, always in the quest of better performance. But airplanes, like people, gain weight over the years through the addition of equipment, dirt, hydraulic fluid, orphan wiring, paint touch-up, pilot paraphernalia and paperwork. Owners are shocked to find that so-called in-service weight gain can easily add a dozen or more pounds to empty…