Sizing up runways

I find it interesting that the sales brochure for Pilatus’s forthcoming PC-24 features a convincing (albeit computer-generated) photo of the business jet taking off from a dirt airstrip. The Swiss manufacturer’s PC-12—a large-cabin, single-engine turboprop—is famous for its ability to operate from rough “unimproved” runways. But a jet? 

Well, if anyone can build a utility version of a business jet, it’s Pilatus.

The picture of that jet taking off from a dirt strip got me thinking of how all airplanes can’t use all runways. It’s pretty obvious that you won’t see an Airbus A380 at a tiny backwoods duster strip, but some cases are not so cut and dried. 

Close to 5,000 airports in the U.S. have paved runways. Fewer than 400 of these have scheduled airline service, and only 25 are major airports serving 10 million or more passengers per year. Chances are, one of the smaller airports is within a few minutes of your home.

Not all of those general aviation airports are created equal, though. That may be obvious when you’re comparing a bucolic grass runway to a bustling business aviation hub such as Van Nuys in the Los Angeles area or Teterboro [New Jersey] Airport (just outside Manhattan). But some middling airports are on the marginal side when it comes to runway length, clear landing approaches, and the sophistication of the electronic landing aids that serve them. So aircraft manufacturers go to great lengths to calculate how much runway works for their airplanes under given conditions. Those parameters are published in the pilot’s operating specifications and the crew reviews them before every flight.

Some elements of the calculation may surprise you. For example, many consider any airplane with propellers to be last century’s news. But a modern turboprop (using turbine jet engines driving propellers) can be far more versatile than a jet. You might sacrifice some cruise speed, but you still have a big cabin, quiet comfort, and all-weather capability. And unlike many jets, the turboprop has the torque and acceleration to safely use a short runway tucked within the mountains or shoehorned onto a remote island getaway.

When it comes to matching aircraft with runways, size isn’t always the bottom line. For example, Essex County Airport in northern New Jersey has a relatively short (for a jet) 4,000-foot runway. You’d think that smaller jets would have an advantage there. But, in fact, most smaller jets such as the Cessna Citation Mustang and the Embraer Phenom 100 have correspondingly smaller wheels. That means smaller brakes that might overheat if applied too aggressively. Also, most smaller jets don’t have thrust reversers—scooped panels near the engines’ exhaust that the pilot deploys after touchdown to catch the thrust and “reverse” it, using engine blast as braking force. So, as odd as it may seem, a midsize jet such as the Dassault Falcon 50 can often operate from a shorter runway than a jet half its size.

Weather conditions also come into play at midsize airports. An airport that might be unsafe to fly into on a hot, humid day with a full passenger load might be just fine when the weather is cool and all the seats aren’t full. Other times, when low clouds necessitate stricter instrument-flying procedures, it might become impractical to use an airport that presented no problem the week before.

The good news is that among those 5,000 paved-runway airports in the U.S., the next-closest general aviation airport is still probably a lot closer to your final destination than one of the “big” airports that serve the airlines.

So while airline pilots almost always have the numbers and the size of the airport on their side, crews of private aircraft have far more airports to choose from. It’s their responsibility to ensure their aircraft can operate safely from the runways that best serve passengers’ needs.