This is the time of year to be sky-minded.
Orioles, finches, and hummingbirds paint the morning air with flashes of orange, yellow, and green. The walnut tree behind our house becomes an aerial battlefield, its leaves providing cover for territorial dogfights, even as woodpeckers hop patiently along its branches, prospecting for mites.
Huge carpenter bees bump maddeningly at the porch screen, while their more nimble cousins, mud-daubers and paper wasps, streak through the jewel weed. These glamorous fly-boys, the jet fighters of the insect world, aren’t the only six-legged critters on the wing. The sky swarms with every manner of midge, moth, gnat, and beetle.
Off in the distance, against the backdrop of Blue Mountain, an outraged blackbird harries a hawk ten times its size, the smaller bird rearing up, then diving for the larger, which glides on, seemingly undisturbed, in ever-widening circles.
High above St. Peter’s Church Road, there’s another world of flight, this one belonging to man. An intrepid ultra-light plows the air with the tip of its delta wing. A hot-air balloon sinks behind a ridge like a Technicolor moon. A 737 descends towards Harrisburg, sharpening the sky like a whetstone.
It’s been a while since I flew a plane, but I still get the hankering now and then. When that happens, I’ll pull out an aviation map and pretend I’m preparing for a flight.
This week, I decided to take to the sky over Perry County.
You can, too, if you’re curious, by going to http://skyvector.com and clicking on the “charts” icon. You’ll see the United States divided into 39 squares, each representing a regional aviation map. The one that covers Perry County is easy to find; it includes Lake Erie, and is called the “Detroit Sectional.”
It may seem strange to find Perry County on a Detroit map, but you need to keep in mind the vast distances that airplanes can cover, compared to automobiles. The last thing you want is your pilot to be buried in a heap of maps. Of course, these days, virtually all cockpits are outfitted with GPS systems. But pilots are still trained the old-fashioned way, with paper-and-ink maps, in case of a failure of the plane’s electrical system.
Some of the features of an aviation sectional will look familiar. For instance, like a topographic map, a sectional shows the lay of the land, because it’s crucial for a pilot to know whether there are mountains en route, and if so, exactly how high they are.
On the other hand, you won’t find many roads on a sectional. Infinitely more important than squiggling roads, to a pilot, are the strange and colorful shapes representing the different classes of airspace.
You spend a lot of time as a student pilot wrapping your head around the idea that the sky is full of invisible boundaries, and that crossing them without the proper clearance from air traffic control can cost you a significant fine or your flying privileges. If you’re careless enough to violate the prohibited airspace over Camp David or the White House, you can count on being intercepted by Blackhawks or F-16s.
Unlike a road map from, say, AAA, which only contemplates the two-dimensional world of earth-bound traffic, an aviation map has to represent three dimensions. A pilot, looking at a map of the airspace over, say, Harrisburg International, has to be able to visualize a kind of upside-down wedding cake over the airport. That invisible upside-down wedding cake represents restricted airspace. If you want to enter it, or pass through it, you need to get permission from an air traffic controller.
Each tier of the wedding cake is very precisely defined, both in terms of its circumference, and its upper and lower altitude limits.
In addition to invisible cakes and no-go zones, there are also invisible highways, called “federal airways.” These are precisely defined, too: exactly eight nautical miles wide, extending from 1200’ above ground level, up to – but not including! – 18,000’ mean sea level. There’s a lot of training involved in understanding, and then memorizing, these things.
But back to Perry County. There’s actually a federal airway right up the street from St. Peter’s Church Road. Its name is “Victor 210,” and it passes between Loysville and Landisburg. Who knew there was a federal interstate hovering overhead?
Happily, aside from V210, the sky over Perry County is most uncluttered, just like the landscape below. The eastern part of the county is under the umbrella of Harrisburg International’s airspace. A bit of the western part of the county falls under the much less restrictive airspace of Stottle Memorial Heliport over in Juniata County.
In other words, airspace has no respect for county lines!
Aside from that, there are very few features on the Detroit sectional to help with pilotage over Perry County. Pilotage is the art of navigating using visual landmarks. There are some major powerlines marked on the sectional, with a hub at the electrical substation in New Bloomfield. There’s the odd telecommunications tower here or there. One feature that I like very much, a tiny black square northwest of Loysville, is labeled simply, “institution.”
You have to know a thing or two about the county to know that this is the Loysville Youth Development Center, the former orphanage.
See? I’m learning.
This column was published in the Perry Co Times on 24 June 2010
For more information, please contact Mr. Olshan at writing@matthewolshan.com
