It seems that every time a new forecast comes out, the weather seems to be taking a long walk down the wrong road. Record-breaking temperatures, rainfall, tornadoes, flooding, massive thunderstorms, and staggering drought—there doesn’t appear to be any relief in sight. Coupled with that are new meteorological terms I haven’t heard before, like heat domes, atmospheric rivers, topical plume, Pineapple Express, etc.
More than any other factor, aerial application is dependent on the weather. Sometimes, Mother Nature seems asleep at the wheel or has a nasty mean streak when it comes to helping farmers combat the latest infestation.
Some good news: aerial applicators can always choose to fly in weather suitable for the specific requirements of the job or park the aircraft when the weather is out of limits and wait until things settle down. While it’s challenging to choose to shut down with a lineup of anxious farmers standing in line at the airstrip, hoping to be the next one to get your aerial application services before their crops are toast, don’t press the capricious gods of nature. It seldom pays dividends and, more often than not, will get you into hot water.
To paraphrase the famous line from Shakespeare’s Hamlet, to go or not to go, that is the question. In the past, it was a matter of looking at the windsock to gauge whether the trip would be safe and effective. That is, if a windsock was present. When I started in the industry decades ago, a lot of flying was done off municipal roads with the attendant lack of weather services.
Today’s aerial applicators have a chest full of new tools, like sophisticated and affordable mobile weather stations that help quantify the decision to fly. Coupled with widespread access to the Internet, you have readily accessible and up-to-date weather information whenever needed.
To those unfamiliar with aerial application, the public notion is of daredevil pilots staging a free and entertaining airshow. Nothing could be further from reality. Compared to the early pioneering cropdusters who spawned a new industry, today’s operators and pilots are better trained, equipped, and managed than ever before.
However, no matter how much you prepare, the skies are ready with challenges that can sneak up on you and spoil a perfectly wonderful day. It is one thing to deal with an issue while you are thousands of feet above ground. It’s a different kettle of fish when you’re skimming over crops at a dozen feet. Here are a few reminders to help keep your guard up.
It is hard to cope with something you can’t see directly, and first and foremost on my list of Mother Nature’s poisoned gifts is the phenomenon of low-level wind shear. It can be a real bummer like its big brother, clear air turbulence. Ask any experienced ag pilot if they’ve ever been bit by wind shear, and you’ll add another story to the next hangar talk session.
The problem with wind shear, a.k.a. steep wind gradient, occurs when a headwind rapidly changes to a tailwind, causing a dramatic decrease in airspeed and performance. This can happen when you’re pulling up into a dramatically increasing tailwind. If severe enough, the perception you get with such a rapid decrease in airspeed is that you’ve just had an engine failure.
No problem if the terrain ahead of you is flat. It’s not so good when you’ve got a powerline, hill or some other obstruction you need to clear. Double that when you have a full load aboard.
Avoidance is the key. Even if it’s lightly gusting on the ground, be on the lookout for a strong wind shear aloft. It’s better to be safe than sorry. Thunderstorms, frontal weather, temperature inversions, or tall trees or buildings can cause localized wind shear.
Although we are taught about wind shear in our commercial ground school, it doesn’t sink in until the phenomena have nipped you. My first and most memorable experience was in a Cessna 188, applying fungicide about 25 miles from my home base. There was a light headwind on takeoff, but on the way to the field, I noticed it was getting bumpier and bumpier as I climbed. At any rate, I could see the field well in advance and decided to enter directly on the first spray run.
All went well until I pulled up at the far end of the field. Luckily, there was only a line of small trees to avoid as I had the awful sinking sensation of mushing during the pull-up, with the airspeed unwinding like a broken spring. Turning back to the field for the next run wasn’t going to happen until I got the AgTruck out of the near-stall condition I found myself in. Only by gently lowering the nose to get out of the wind shear around 300 feet was I able to get back to a fully flyable condition.
I also recall that it took a couple of miles to achieve that goal of doing a 180 to line up with the next swath, all the while feeling like I was trying to balance precariously on a beach ball, trying somehow to maintain stability where any sudden movement could lead to a nose-dive. Or, in the case of the AgTruck, use gentle movements on the stick to avoid a stall and unwanted contact with terra firma.
There is no shortage of events that could lead to a day you’d rather avoid: inversions, mechanical and thermal turbulence, flight into rising ground. The list goes on and on. But when considering whether to go or not to go, remind yourself that it is best to be prudent when faced with a risky situation rather than charging full steam ahead.
Keep the math simple. One of your primary goals is to have the same number of landings as takeoffs so you can avoid becoming an unwanted and preventable statistic.
