Never Again: Glider updraft

April 1, 2009

Many pilots have had an experience in their past that they are amazed they survived. And the added perspective that years of hard-won experience and knowledge bring can make our survival from those earlier mistakes and misadventures seem all the more incredible. As a college student and fledgling glider pilot, I was looking forward to making a cross-country flight from Waverly West Gliderport (now known as Owl Canyon Gliderport) near Fort Collins, Colorado, to Laramie, Wyoming, about 44 miles north. It would be my second cross-country glider flight, and I would use our club’s single-place Schweizer SGS 1-26. I planned a leisurely two-hour trip with lots of circling and climbing along the way.

I was confident in my ability to perform the flight safely in spite of my inexperience. In the back of my mind, I could hear my instructor, Fred Herr, warning me to “never go near a dark-bottomed cumulus cloud—it can suck you up!”

With his words echoing in my ears, I dressed for the Colorado summer: shorts and a T-shirt. Before noon, the temperature was already in the high 80s. Gliders with their greenhouse cockpits can get extremely warm, even at relatively high altitudes.

I brought the Cheyenne VFR sectional chart as well as road maps for Colorado and Wyoming, drinking water, and a snack. Packed away in the event I had to land out was a small survival bag that held appropriate clothing for the colder nights.

The weather forecast called for a weak cold front to pass through the area, moving in a northeasterly direction, in the middle of the afternoon. I had experience with dry thermals that materialize on summer days in the region; however, the front was likely to bring some additional thermal activity along with it. Perhaps the front would bring some moisture and cooler temperatures and show the rising air with building clouds—a much easier way to find lift than blindly having to feel for the dry thermals.

The route was pretty simple. Find U.S. Highway 287 a little less than 10 miles west of the gliderport, and follow it northwest to Laramie. If following a highway wasn’t simple enough, the Rocky Mountains also pointed the way. I could just follow alongside the foothills leading north to Wyoming.

The launch took place as planned just after noon. I had coordinated with the tow pilot to climb in a westerly direction that would get me closer to U.S. Highway 287. At about 7,500 feet msl (2,000 feet agl), the Super Cub tow plane and I flew through a thermal. I pulled the release handle and watched the towrope fall away. Then I turned right, away from the tow plane, and found the center of the thermal, gaining about 1,500 additional feet. It was a promising start! I headed west again in the direction of the highway and the multitude of potential landing areas alongside it.

Spotting the highway, I turned to the northwest. Visibility was unlimited. I could see Laramie already. The sky was cloudless, even over the mountains immediately to the west.

There were no clouds to mark the thermals, and I worked hard to find rising air. Despite my best efforts, however, I was descending about three feet per second. The terrain rose to 6,500 feet msl, and soon I was down to 7,700 feet msl—just 1,200 agl. I knew the cross-country golden rule about altitude. You are committed to land at 1,000 feet agl. No more attempts at thermals. Unless I could find some lift in the next few moments, I would be forced to pick a field and land short of my destination. It wasn’t the end of the world. I’d done it before. But I was looking hard for a way to avoid it.

I searched nearby pastures for fences, rocks, anything that could damage a glider as I prepared to select the best field to land in. I evaluated the wind speed and direction and found an acceptable spot. Then I set up a landing pattern that would allow me to set the glider down, into the wind, on a flat piece of ground. The sky overhead was still clear, and I saw little prospect of being able to continue my trip.

I set up a downwind pattern and made a final evaluation of my chosen landing site. Everything looked good. Just then, however, the variometer showed a sink rate of zero. That got my attention. I could circle in this little bit of lift and see what developed.

I made one, then two, then three circles, and the altimeter began to wind up. Another few turns, and I was at 7,700 feet again, and the variometer now indicated a climb of 150 feet per minute. There was a small, puffy cloud directly above, and it marked the area of greatest lift.

With each circle, the variometer needle lifted a little higher, just as the thermal lifted me. Soon I was at 9,000 feet msl and could see over the peaks of the foothills. Scores of cumulus clouds were now dotting the range. I noted the white puff of cloud that once innocently marked my thermal was getting larger—fast—and it developed a menacing flat, gray, well-defined base.

The altimeter began to wind up faster and faster. The variometer showed a 1,500-foot-per-minute climb. This is great! I thought. Another circle and I’d be at 11,000 feet msl and turn back on course to the northwest.

Finishing the last circle I looked forward, and I could no longer see the horizon. The edge of the cloud extended below me all around. I looked up to see a concave black cloud base with the apex still about 1,000 feet above me. I was in the middle of a colossal black kettle turned upside down. The sight left me breathless—I was truly awed.

Awesome only partially describes the moment. At that instant I had a kaleidoscopic experience. I saw the first lightning. Hail began to beat on the canopy, and freezing droplets began to coat the leading edge of the wing with ice. I felt the cold quickly reach down into my bones. No doubt the cold I felt came more from the realization of my predicament than the drop in air temperature.

I immediately dove the glider, aiming to escape the cloud by slipping under the edge. With spoilers pulled and diving at 114 mph, redline, I was still going up at nearly 800 feet per minute! I considered I had one option to break away from the overpowering suction of this cumulonimbus. I turned and then leveled the wings on an easterly heading and held on tight. I entered the side of the cloud wall at 114 mph with spoilers out. After an eternity or two, I rocketed out of the cloud wall at about 14,000 msl, escaping the monster cloud.

I continued the flight eastward, eventually landing in a newly plowed field near Scottsbluff, Nebraska. I waited for my dad to bring the trailer to drag the glider back to Waverly West, sitting in a café drinking 25-cent draft Michelob and contemplating my instructor’s previous advice. His words were no longer a faint whisper. They practically rang in my ears.

Frank McDonald, AOPA 760221, is an instrument-rated commercial pilot with glider ratings and more than 2,400 flight hours.