The first downdraft hit like a giant hand pushing down on the top of the airplane. I need power! Mixtures full rich, props full forward, throttles … push, push, they’re all the way to the stops! I was still descending, 8,000, 7,000, finally stopping at 6,000 feet. Out the windshield was an ominous green color, about the color of a sprout of peas. As quickly as the downdraft stopped, an updraft started. No matter what I tried, I could not hold altitude. Throttles idle! Control yoke, push forward! Push, push, push hard! The updraft ended very abruptly, like hitting a ceiling. The altimeter started unwinding one more time, but this time the artificial horizon tumbled. The abrupt end to the updraft did internal damage, loosening the forward instrument panel. One male passenger was screaming, begging me to get him out of this storm. I was doing all I could just to hang on.