Ray KR4PQC

Weather Radar, Air Traffic Control & Thunderstorms: a primer for non av-geeks. Thunderstorms are an obvious threat to airplanes, but how does staying out of them work? To begin, we plan our routes to try & avoid areas forecast to develop storms. This happens long before we ever get to the jet; at the airlines, a dispatcher builds the flight plan & the Captain approves it. The dispatcher looks at all the weather forecasts & determines the most efficient route & altitude, while avoiding storms. Still, it’s not always possible to completely avoid areas where storms may develop later; doing so may add hundreds of miles to a route. If you can’t go around the storms, sometimes you can go over them…if you can clear a storm by at least 2,000’, you should have no issues. But, that’s not always possible, either, especially as you get more toward the equator, where storms can grow higher. We also can’t immediately climb to our maximum altitude…it can take several hours to burn off enough fuel to be light enough. So, at some point you have to make the best plan you can & give it to the crew to execute. If that’s the case, they’ll usually give us extra fuel to help when we need to deviate around storms. Once in the air, we have several tools to help us detect & avoid storms. By far the best is our onboard weather radar, but I’ll save that for last. My first resource is my airline iPad. It has various apps specific to aviation, including weather apps. My planned route can be overlaid on ground radar returns of the storms, including (radar) “Echo Tops” – estimates of how high the storms reach. It’s a great tool for longer range planning. I can see what’s happening way down the line, where on my radar, I start not trusting any returns further than 80 miles away (I’ll discuss that). That’s important as I start making a plan; I could choose to deviate left or right, but it’s possible I deviate toward something that’s going to be worse for me later on. Storms can be deceiving & can lure you into “sucker holes”…areas that looked clear, but you get in there, realize it’s anything but & wish you’d made a different decision. Which brings up a good point: if you do find yourself penetrating a storm, you just fly straight through it. Make no attempt to turn around, that’s going to be worse for you than just pushing through. I’ll continue to tie the iPad into this, and it will start sounding like magic. It really has been great for us, but when the WiFi cuts out, it’s not so great. Also, even with good WiFi, the data can get “stale”…a radar picture of a thunderstorm that is 15 minutes old or more can be more risky than having no picture at all, as it leads me to assume something that isn’t true. Similar to a sucker hole. After the iPad, I have Air Traffic Control. ATC’s radar doesn’t work like a weather radar & they can’t see storms the same way we can or your local TV weather person shows you. Sometimes they’ll see storms that don’t actually exist. Nevertheless, they know there is weather out there & will advise you of it. That’s appreciated, but in this age if your first indication comes from ATC, you are doing things wrong. ATC has a lot of value, though, and beyond their normal assets, they have a bonus: they know what everyone else has done before you & how it turned out. It’s not uncommon to hear ATC get asked “is anyone getting through that gap at 11 o’clock?”, “where are the tops (how high does the storm go, reported by other jets)” or “how is everyone else getting around this?” Now, we have some ability to see other traffic on our iPad, with the weather overlay, and we can detect patterns…everyone suddenly turns South when approaching a storm & that gives me a heads up that this is likely the best route, even before I’m talking to that sector of ATC & can ask. (Continued…)