Slinging through a storm

The two souls aboard were Jean d’Assonville and Wayne Toddun, co-chief executives of the Sling Pilot Academy in California, recently created to offer professional training in the South African-made Sling TSi and other aircraft. The pair were on their way to Sun 'n Fun International Fly-In and Expo to represent The Airplane Factory, which produces both kits and factory-made versions of the two- and four-seat aircraft of which the Sling TSi, first introduced at EAA AirVenture in 2018, is the most recent. Powered by a turbocharged Rotax 915 engine with full authority digital engine control, Toddun’s Sling TSi is registered in the United States as an experimental aircraft. This was not the longest nonstop flight d’Assonville had made in a Sling, not by a long shot. He said during an interview on the Sun 'n Fun grounds that the duo considered landing at an alternate airport, but they were confident they could press on.

Cruising at 17,500 feet and sipping 6.8 gallons per hour at 155 knots, d’Assonville and Toddun, a Sling buyer who liked the aircraft so much he joined the company, made good time from Torrance, California, to Louisiana, where they ran into a front.

“Things were going well until we hit weather,” Toddun recalled. The storm line proved too much to climb over, even in a piston aircraft that has flown as high as 23,000 feet. Toddun said the pair tried to “kind of make our way through it up high and just got murdered” by turbulence.

They opted to briefly double back west and descend, staying clear of clouds and maintaining sight of the ground, then headed out over the Gulf of Mexico so they could descend lower still. They eventually found relatively smooth air and good visibility—at about 300 to 800 feet over the water.

“We didn’t want to be unsafe,” Toddun said, adding with a smile and a laugh that, “not making it would have been really bad publicity for us.”

Battling 37-knot headwinds down low, the pilots put their heads together and worked the math to make sure they had enough fuel on board, including the ferry tanks, a set of five-gallon vessels in the back seat connected to the main fuel system with transfer pumps that allowed them to carefully meter their fuel. “We had to make some decisions.”

They reduced power and watched the fuel burn drop to a more economical range, 4.2 to 4.6 gallons per hour. They rechecked their math and figured they’d still reach Florida with 1.5 hours of fuel to spare.

“That just changed the whole equation,” Toddun said. “We’re doing about 100 knots all the way across. You wouldn’t do that if you didn’t have faith in the aircraft."

D’Assonville has made flights in a Sling as long as 27.5 hours, carrying a bit more fuel. He said there was always “an escape route available,” in that they could have opted to land at any number of coastal airports along the way. The five-gallon tanks were mostly empty by this point in the flight, and could have served as flotation devices had they been forced to ditch, d'Assonville said. The sophisticated technology of the FADEC-controlled Rotax supplied much better awareness of their fuel state than most general aviation pilots enjoy, to the point where their actual fuel burn, measured after arrival, was within a tenth of a gallon of their in-flight calculations.

A ground support team tracked their progress through a GPS beacon they carried, and the pair also relayed position reports along the way by contacting airliners on 121.5 MHz once they were flying low over the water, still aiming to get to Tampa and then Lakeland, Florida, in time for the big show.

“It wasn’t a stupid mission,” d’Assonville said of the long-distance trip. “It was something we’d done before.”

The pair landed safely after a 1,900-mile journey that lasted 13.5 hours, including that slight diversion south and low to accommodate conditions. They were in Lakeland in plenty of time to set up for the show, where they pitched an aircraft that costs $164,062 for a factory-assisted quick-build kit with engine, avionics, and constant-speed propeller. D’Assonville said the factory can complete the aircraft for another $80,000 or so, and it has plenty of range to cross the Atlantic Ocean, as he has personally proved. (A two-seat light sport aircraft version is also available; learn more about The Airplane Factory and the Sling models it produces online.)

The seats are apparently comfortable enough for a long trip. Watch for a detailed story on this aircraft in an upcoming issue of AOPA Pilot.