Weather Avoidance
I began flying a Piper Malibu earlier this year. For those of you not familiar with the original PA-46, a Malibu has a Continental TSIO-320 engine, with 310 HP. It’s pressurized and cruises at about 185-200 KTAS.
A few things are introduced to the equation when pilots start flying higher, faster, and farther. When you start flying over longer distances, weather becomes more of an issue. On a quick hop from, say, Austin to Dallas, you can be pretty sure of what the weather will be since it’s a short trip. When you fly from Austin to LA, leave in the morning, land once along the way, and arrive in the afternoon after spending six and a half hours in the air, weather can change a lot in that amount of time.
A must for any pilot flying high and over long distances is some kind of Nexrad system, whether it be a Garmin 696, or it shows up on your GPS or MFD. Having this situation awareness is very helpful when planning ahead as to what to do about weather. A stormscope is also a handy tool, since you can see where the lightning is with it.
Cold fronts can be pretty nasty, depending on how strong and how fast they are moving. A strong, fast moving cold front usually has a lot of convective activity associated with it. The tricky thing with storms associated with fronts is that storms form in lines, most of the time. If you’re trying to cross a front in the morning, you can usually get high enough over the clouds with a pressurized airplane since the temperature is still relatively low to get clear of the cumulonimbus clouds. The cloud tops will only be around ten or twelve thousand feet.
Crossing fronts in the afternoon when daytime heating is pushing the tops of the CBs up to the 20-40 thousand foot range, it’s best to land, have a meal, stretch your legs, and wait till the sun starts to go down before pushing on. Do not, under any circumstances, try and go through the cumulonimbus clouds associated with a cold front in a small airplane. Not only is it uncomfortable (the turbulence bounces you around pretty good), but you’ll get ice, scare the passengers, and, if you’re in the heart of a storm, the plane could come apart.
When crossing mountains, the weather is always highly unpredictable. If it’s a clear day, no matter your altitude, you’ll probably pick up some turbulence from all the rising air off the peaks. If there is moisture in the air, there are going to be isolated to scattered thunderstorms in the summer time. The advantage of flying high when there are isolated or scattered storms is you can utilize the see and avoid method.
See and avoid is simple. When the storms aren’t embedded in other clouds, it’s actually rather easy to spot the big, rising clouds and go around them. The same concept holds true when avoiding those pesky pop up thunderstorms in humid areas like Houston and Florida.
One thing that I learned this summer was this. Sometimes, with an area of closely grouped storms, the cloud base is actually quite high (some storms I went underneath in New Mexico had cloud bases of 15,000 MSL). The thing to do here is just stay below the bases of the clouds and go around the areas of rain. These will be visible and you’ll be able to navigate around them. With bases even as low 9-10 thousand feet, it’s a much better idea to stay below the clouds, sacrifice some speed, and dodge the rain shafts.
The most important concept to take away is don’t fly into a thunderstorm. If there are a bunch of really high clouds in front of you and you don’t see a safe way around them, descend down and land, wait it out, and then continue on your way.
