CAT: Clear Air Turbulence
We left at dawn on a mission, for no other reason than to explore the reaches of the Mississippi River. The famous river where the Lewis and Clark expedition began; Jolliet and Marquette, the Vicksburg campaign, and 100 pound catfish. The plan was to follow the tributary as it snaked it’s way North from Illinois and Iowa to Wisconsin and Minnesota. We lifted off the runway and the flat roofs of hangers soon transformed into small matchboxes. Fields appeared, spanning in all directions. The earth became limitless, with the horizon appearing in the haze. It was a smooth ride, in fact as smooth as it gets. It was unknown at this point that Mother Nature planned a sucker punch.
Before long, the river was in sight and we turned right 90 degrees. Tom was in the right seat, handling radios and navigation which was pretty much looking down at the river. Of course he could take a turn at the wheel so as to provide a break and some photo snaps. Perspective changes from this vantage point. The great Mississippi ranges in width from one to four miles but from here it looked like a shiny brown ribbon. They don’t call it the big muddy for nothing and I liked the idea of touring from above than with the barges below. They appeared immobile, if it wasn’t for the burbling of wakes at the stern.
North we cruised. Old river towns passed by mile after mile. I thought of riverboats that used to ply these waters when my thoughts were interrupted by a voice on the radio. Air traffic control came on line to advise a”target” was on the same heading, same altitude. “Be advised that both targets will merge in one minute”. A polite euphemism for mid air collision. Without traffic in sight due to increasing haze, I changed altitude and veered ten degrees until we could see a light airplane passing on the left. All was well when we landed at the LaCrosse Airport, an Island, surrounded by tentacles of water. Time for fuel and a quick check with the Flight Service Station (FSS). These people provide a storehouse of information on weather, navigation aids, local and distant airport information, ability to file flight plans and did I say weather? There was an Airmet (Significant weather concerns for light aircraft) for severe turbulence. Not light chop but severe. Pshaw, I said. We just flew a great length of landscape and surely you must be mistaken. (The briefer asked that I not call him Shirley). Press on we would. Besides, our options were limited. It would mean spending the night in some fleabag motel which was not part of the plan. How bad could it be?
We launched back into the blue and, in ten minutes, it became bumpy. No problem. It’s all part of the experience of flight. However, another fifteen minutes later, it felt as if a giant hand pushed us skyward. Then the same invisible force pushed us back down. The instruments were pegged at 2,000 feet per minute and we really didn’t have that much altitude to spare. Then to spice things up, the same mystical force provided uncommanded roll. I was trying to over control but I remembered that it overstresses the aircraft. The unseen force decided slap the plane around as if to punish us for not obeying the voice of reason, the FSS gods of meteorology. No clouds –this was clear air. While this probably lasted for 20 minutes it seemed much, much longer. I left grip marks on the glareshield and promised to repent from the error of my ways. Tom didn’t say much aside from the occasional “whoa”. He was kind enough not to mention that any smart pilot wouldn’t have launched in the teeth of very turbulent air. I decided that if it didn’t get worse, we would head to the next destination. We were half way, rivets weren’t popping and there was nowhere to land in the rolling hills.
We finally landed at the next airport before heading for home, the wind sheer was relenting and so were our stomachs. We stopped to eat but mostly pushed food around the plate. More lessons into the bag of experience. First: The FSS folks do know what they’re talking about. Second: What you can’t see can potentially hurt you. It’s better to be on the ground wishing you were in the air than in the air wishing you were on the ground.