Acknowledgements: AIR FACTS – John Zimmerman

 (Ed. Note: A slightly abridged edition of John’s original article, which can be read in full on the AIR FACTS website)

 “Summer days are long, the kids are out of school, and there are adventures to pursue .... unfortunately, the one drawback of summertime flying – thunderstorms .... the good news is, it’s fairly simple to avoid the worst weather; it just takes patience and discipline to go all the way around it .... 

 The pilot is in command

.... ATC radar can help, but its main job is to separate airplanes, not paint thunderstorms. Consider how the balance of power between pilot and controller has shifted over the last 20 years though. Once, ATC was our main weather resource .... today, with datalink radar in almost every cockpit, pilots have as much (if not more) information than ATC. 

 .... That means pilots need to set the agenda, and not wait for ATC to make a suggestion. If you see a solid line of red on the radar screen or even towering clouds out the front window, make a plan to avoid them early on and be proactive about sharing it with the controller .... While it may sound arrogant, the pilot in command should tell ATC what they want to do, not ask permission .... set the proper tone: “I need to deviate for weather,” instead of, “I’d like to deviate if it works for you.” In my experience, almost all reasonable requests are granted. 

 .... Often ATC will grant a blanket clearance to deviate as much as needed. In busy airspace you may not get that much leeway so if the controller asks for specifics, be ready with a realistic but conservative answer. If the deviation is going to be a long one, instead of asking for 30 degrees right for 80 miles I’ll add a VOR or intersection and make a dogleg out of it. In general, this works well for ATC since they can put it in the computer and pass the plan along to the next sector.

 .... When asking for that deviation:

·      First, be friendly and succinct. If you’re deviating, there’s a very good chance other airplanes are too, so cut the controller a little slack; assertive is fine but aggressive is not.

·      Secondly, make sure to ask early. Some requests will require coordination with another sector and that takes time. If you only give the controller 15 seconds to approve your turn, you’ve set yourself up to fail. 

·      Finally, be flexible on altitude if possible, as sometimes a deviation can be approved only if you climb or descend.

 .... The plan is simple: stay visual and avoid all the bumpy-looking clouds, while using datalink weather to maintain a sense of the big picture and ensure you always have an “out” .... This is what I call “fly to the blue sky” navigation – I simply take what Mother Nature gives me .... it’s really easy as long as you don’t get impatient. The key step that some pilots ignore is to clue ATC into your plans.

 .... Sometimes you just have to go around the weather – all the way around .... that highlights the key to flying around thunderstorms in piston airplanes: stay visual if at all possible. That definitely gives you more information than ATC; and keeps the flight comfortable for your passengers.

 .... Of course, pilots aren’t all-knowing weather gurus, and there is an important caveat when it comes to telling ATC what you’re going to do .... first try to determine if ATC has a good feel for the weather that day, and if they have their own plan. Experienced controllers in busy airspace are often a step ahead of you, so it pays to listen with an open mind .... ATC does a great job of routing airplanes around storms – but remember YOU are PIC .... follow ATC’s plan, but back it up with the datalink weather picture and the view out the window ....

 .... Flying around thunderstorms is all about flexibility and patience. That magenta line is just a suggestion, so don’t get locked into a direct route if the weather doesn’t allow it. And no matter where you deviate, always have an “out” .... a “real out” that you are prepared to use, and continually monitor it as conditions change .... find a route that goes all the way around, then work as a team with ATC to do it safely”.


Tony Birth