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Never AgainNever Again

Caught by the waveCaught by the wave

It was a lazy, sunny Southern California Saturday in the winter of 1998, when my morning paper reading was interrupted by the ringing telephone. My son was calling from Mammoth Mountain, where he had been skiing with his father. A storm was predicted for the next day and they had decided to leave early. He would be home in eight hours. My husband, Fred, teased that we could be there in an hour in our Cessna 210 to pick him up, making the ride a lot faster and more fun. A call to weather confirm.ed clear-as-a-bell conditions, so a deal was struck for Fred and I to fly up to meet at noon at Lone Pine, a one-hour drive down from Mammoth, in the Owens Valley, just east of the Sierra Nevada.

We had bought our airplane just 10 months previously, and as a student pilot, I had already flown all over the United States with my husband and our three kids, ages 10, 9, and 6. Fred and I typically share flying duties. My husband has been flying for more than 25 years and was a Navy pilot. On this day, Fred was at the controls, flying GPS direct over the mountains at 13,500 feet with Mount Whitney to our left and the snow a mere 500 feet below us. The view was breathtaking, the air cold and smooth.

We approached the eastern edge of the mountains, where the terrain drops almost straight down to the Owens Valley. Not far away is Death Valley, below sea level. The plane crossed the ridge and suddenly everything went wild. The first bump knocked our headphones off and our heads into the ceiling despite seat belts. The GPS-indicated groundspeed jumped from 175 to 228 knots in a few seconds. If you can imagine floating calmly in the ocean and suddenly being sucked over the edge of a 20-foot wave, you have the idea. There was no turning back; the wind was simply too strong. Fred cut the power to idle in an attempt to keep the airspeed down. The winds swirled wildly around us, and Fred valiantly kept turning the plane with the wind so we wouldn't roll. The vertical speed indicator was pegged, but a digital multifunction instrument on the copilot's side told the story — 7,300 fpm down would end in another violent jolt, followed by 8,200 fpm up, followed by our heads slamming into the ceiling, followed by 5,700 fpm down.

This went on for perhaps eight minutes, and slowly the rotor pushed us over the center of the valley. As we were able to lose some net altitude, I perceived a slight improvement in our condition. But how to land in this? I needn't have worried. By the time we got to the airport, the wind was completely calm.

We stepped out, knees wobbly, to completely still, warm air that felt like velvet when you breathed. A few minutes later, my son and ex-husband pulled up.

"How was the flight?"

"Oh, just fine," we said with smiles as we gathered the boy's things. Obviously, we weren't flying back the same way that we came. Since it was so calm down low, we decided to follow U.S. 395 south out of the valley.

Incredibly, the kids got right back into the airplane with us, and we set off. A few miles south of the airport, we were hit with a blast of wind from the side, coming down the lee of the mountains. With each second the velocity increased, and we were only about 200 feet agl. We peeled off to the left for a quick one-eighty. "Let's try to climb out to the north instead," I suggested. By the time we reached 9,000 feet, however, the turbulence had increased again. It was time to quit. We landed, walked to town, and spent the night in a motel.

Standing at the edge of town, I turned and saw the biggest lenticular cloud I have ever seen, over the center of the valley. Was it there before? I'll never know. That night we found out after calling flight service that the winds across the ridge were reported to exceed 72 kt. We departed at sunrise, the wind much calmer, but we still encountered a few bumps on the way out of that valley.

What did we learn? Always check the winds aloft when flying in mountains. Mountain wave conditions can exist whenever the winds at ridge level are greater than 25 kt. Also, check the barometric pressure. If there is a large difference from one side of a mountain pass to another — wind flows from high pressure to low — you will get bumped on the lee side. Allow at least 2,000 feet between you and the mountain to avoid rotor. And watch approaching cold fronts in winter with cold, stable air.

I now fight fear whenever I feel bumps in conditions that could theoretically lead to even moderate turbulence. My husband learned to respect nature's power, now that he can't just point his F-14 in the opposite direction and get out of it in less than a minute. The Owens Valley, in the lee of the Sierra Nevada, and Boulder, Colorado, in the lee of the Rockies, are two spots that harbor the most extreme mountain wave turbulence. I have learned to give any mountain plenty of room.

Crista and Fred Worthy own a Cessna 210.

"Never Again" is presented to enhance safety by providing a forum for pilots to learn from the experiences of others. Manuscripts should be typewritten, double-spaced, and sent to: Editor, AOPA Pilot , 421 Aviation Way, Frederick, Maryland 21701.

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