Flying ‘Way Up There’

Getting a Lear to Flight Level 510 before running out of jet-A was a challenge. Nonetheless, I was learning about the benefits (and perils) of high-altitude flight.

[File photo: Shutterstock]

We're going to Texas.

“I doubt it,” I thought, after looking at the radar. There was a line of thunderstorms associated with a cold front stretching north to south across our route.

“Nah,” said Jason, “We’ll fly above that stuff.” Such was my introduction to flying jets, in this case the Lear-jet 31. With a service ceiling of 51,000 feet, there weren’t many clouds we couldn’t top; at least theoretically. I say theoretically because getting a Lear to Flight Level 510 before running out of jet-A was a challenge. Nonetheless, I was learning about the benefits (and perils) of high-altitude flight.

Starting out in a Cessna 150, altitude was a pretty simple matter. With careful attention to density altitude, most takeoffs were possible and cruising altitudes were seldom much more than a few thousand feet above mean sea level.

Owning a Cessna P210 got me thinking about pressurization, advantages of flights in the high “teens,” and the thrill of announcing my presence at a flight level. Though credited with a service ceiling of 25,000 feet, I doubt I ever made it higher than FL210. That was exhilarating enough for me. A Hank Williams Jr. song called “High and Pressurized” became my anthem. “It don’t take long to get there if you’re high and pressurized,” went the first verse. It is a tune about the satisfaction that comes with owning or renting a pressurized airplane. There’s a line about the mile high club, but that’s a topic for a different day (and maybe a different publication).

Pressurized piston airplanes have the admirable trait of being able to fly low into headwinds and to ride the tailwinds up high. Turboprops aren’t so lucky. These airplanes basically have jet engines that are more fuel efficient the higher they fly, so bucking headwinds down low rarely makes sense over long distances. With service ceilings of 28,000 to 31,000 feet, you aren’t going to top any big thunderstorms in a turboprop either.

Jets, however, make surmounting the weather a real possibility. That Lear 31 trip was my introduction to such magnificence. In fact, we laughed at my naiveté and at the wall of lightning and mayhem beneath us as we roared westward at FL430. Later that night, we retraced our route from Texas to St. Petersburg, Florida (KPIE), and climbed to FL470. We would have kept climbing, but the peninsula of Florida was fast approaching—and we didn’t want to overshoot and end up in Spain.

I don’t know how high I have been. I mean that in a strict sense of altitude msl. Redeeming mileage points, I rode on Concorde once from KJFK in New York to Heathrow (EGLL) in London. After much whining and begging, I was allowed to enter the cockpit. I was astounded to see the altimeters showing 52,640 feet (I think). Given a block altitude (who else was going to be up here?), the pilots said they just sought the best altitude for the prevailing winds and temperature. The airplane was so fast—it routinely cruised at Mach 2.0—that eastbound trips and westbound trips weren’t but a few minutes different in regards to time en route. Soon, I was ushered back out of the cockpit by a stern British Airways flight attendant, so I really don’t know how high we actually got.

Part 135 flying in a Cessna Citation CJ3 was my real classroom for learning about high-altitude flight. With a straight wing and hence relatively docile flying characteristics up high, we consistently flew at FL450 when possible. With generous and knowledgeable captains, I learned that although we could top those huge Midwest thunderstorms at FL450, it was still a good idea to avoid flying directly over them. Just because it looked clear didn’t mean there weren’t ferocious funnels of turbulence rising from these prodigious forces of nature.

I’m currently privileged to fly a Cessna CJ1. Its service ceiling is FL410, but I had never been that high in it until recently. Powered by two Williams FJ44-1A engines with a “mere” 1,900 pounds of thrust each, the CJ1 never seemed very enthusiastic about flying above FL390. Then I was taught a lesson.

“I don’t know how high I have been. I mean that in a strict sense of altitude msl.”

While the airplane was parked at Wichita’s Dwight D. Eisenhower National Airport (KICT) for a routine maintenance visit, the Textron Aviation service center per-formed scheduled engine checks and replaced some seals. As part of their post-maintenance protocol, they flew the airplane. I watched with amazement on as the Textron pilots flew right up to 41,000 feet.

Two days later, I was headed from KICT to Lebanon, New Hampshire (KLEB), a distance of 1,200 nm. With just a modest tailwind and me as the airplane’s only occupant, ForeFlight calculated I would land with 908 pounds of fuel. Though certainly legal, my personal minimum is 1,000 pounds of gas upon landing. Good weather was forecast at the destination for the next eight hours. After that, Hurricane Irma was to wash the Northeast clean.

I decided to start out with the intent to climb to FL410,carefully check position, time en route, and fuel consumption against ForeFlight’s nav log, and see what happened. Thirty-nine minutes after takeoff, I was level at 41,000 feet; better than the 48 minutes shown on the navlog. The airplane felt exhausted, as if it had flung itself onto the shore after a difficult marathon swim, but gradually recaptured airspeed such that I was soon clocking 357 ktas and 0.62 Mach, as predicted.

The tailwind was slow to materialize but fuel flow was down to 320 pounds per side, less than 100 gallons an hour. The Avidyne 550s showed me landing with 855 pounds of gas—not ideal, but that didn’t include fuel saved when the power is retarded for descent. This number also improved when those 60 knots of tailwind made their long awaited appearance.

So, I sat there, fat, dumb, and happy. In time, the Nexrad radar update showed me skirting the hurricane and zooming along at a groundspeed of 435 knots. I was euphoric. I poured a cup of coffee and nuzzled the oxygen mask. I’m told the song “Eight Miles High” by the Byrdsis about drugs. With the cabin altitude at just over 7,600 feet, hot coffee at my side, and improving estimated fuel-at-destination calculations, I required zero drugs for mood enhancement.

Oh, yes, I landed with 990 pounds of gas and a 1,200-mile smile.

Editor's Note: This article originally appeared in the Q2 2022 issue of FLYING Magazine.

Dick Karl
Dick KarlAuthor
Dick Karl is a cancer surgeon who appreciates the beauty and science involved in both surgery and flying. Dick’s monthly Gear Up celebrates the human side of flying. He writes about his enthusiasm for both the machines and the people who fly and maintain them.

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