Cessna Once Tried To Build A Four Engine Mini Airliner For Businesspeople, Then Immediately Killed It

In the years following World War II, general aviation saw a boom in popularity, which Cessna leveraged to produce celebrated aircraft including the ubiquitous 172 Skyhawk. Interest in business aircraft also experienced its own rise in demand, and Cessna wanted in. Since business aircraft of the day often lacked refinement, Cessna saw an opening for a quad-engine plane to rule them all. The Cessna 620 was like a mini airliner, and though it was technically advanced, Cessna killed it before it had its chance to shine. Here’s how Cessna built a great business plane that ultimately didn’t make it.

For most people, the name Cessna evokes images of little high-wing single-engine piston aircraft found all over the world. Indeed, the Cessna 172 Skyhawk is the most popular single-engine aircraft ever built and the rental trainer of yours truly. Businesspeople are likely more familiar with the Cessna Citation family of private jets. Citations have been Cessna’s business travel bread and butter since its introduction in 1972 and over time, it has become the largest business jet family in the world. However, Cessna’s efforts in business aviation predate the popular Citation. To understand how Cessna eventually reached the Citation, we must go back to a time when business aviation was still finding its way.

Humble Beginnings

The story of how Cessna came to be is a motivational one. Clyde Cessna was born in 1879. In his early years, Cessna taught himself how to work on machines and used his newfound engineering skills to improve farm machines and farming methods. Later, Cessna would run a car dealership.

As Wings Over Kansas explains, what got Cessna into aviation was seeing a flying exhibition in Oklahoma City. There, Cessna found a new dream: taking to the skies. Learning that air show exhibitors were paid up to $1,000 per show cemented that dream of flying. In 1911, Cessna built his first airplane and through trial and error, taught himself how to fly. Cessna’s first aircraft were built out of wood and fabric and each year, Cessna would build new and improved aircraft. Cessna would take his monoplane to county and state fairs as well as airshows all around the Midwest and reaching as far south as Florida. His plane would hitch a ride on a trailer to get to said shows.

Cessna would continue to improve on his aircraft designs and in 1925 he became the first president of Travel Air Manufacturing Company. Two aircraft, the “City of Oakland” and the “WOOLAROC,” reportedly set Trans-Pacific records two years later. Cessna would leave Travel Air in 1927, teaming up with Victor H. Roos to create the Cessna-Roos Aircraft Company. That year, Cessna developed his characteristic cantilever wing design.

Textron Aviation, the current owner of Cessna, notes that Cessna’s cantilever design became and remains the industry standard. Later in the year, Roos resigned and the company’s name was changed to the Cessna Aircraft Corporation.

Cessna would eventually lose control of his company and Cessna Aircraft would close its factory in 1932 during the Great Depression. In 1934, nephews Dwane and Dwight Wallace teamed up with Cessna to regain control of the company and set it back on a path of fortunes. In his later years, Cessna retired back to a life of farming. He passed in 1954 at 74 years old.

Planes For Every Niche

As the Cessna Flyer Association writes, Cessna rode an explosive wave of demand after World War II. People wanted to go flying and Cessna Aircraft was there to fill as many roles as it could. This era saw the introduction of some famed aircraft. In 1946, Cessna restarted commercial production with the Model 120 and Model 140, both high-wing, tailwheel two-seat general aviation aircraft. The Model 140 was so popular that Cessna says in 1948, it was awarded “Outstanding Plane of the Year” by the U.S. Flight Instructors Association.

Cessna in those days liked filling niches and thus, the Model 120 was a model 140, but with equipment removed to make it cheaper. Later, Cessna would build the 170, which was initially a Model 140 but with two additional seats and more power. All three models would get metal-covered wings in 1949.

Later, Cessna would create the twin-engine 310 in 1954 and the Cessna 172 Skyhawk in 1956. As I said before, the 172 Skyhawk is something of a Honda Super Cub of the skies. With well over 44,000 copies built and still in production today, Cessna claims it is the most popular single-engine aircraft ever built. The Cessna 310 is notable for being Cessna’s first twin-engine design since World War II.

One niche Cessna didn’t cover was large business aircraft. As Plane & Pilot magazine writes, by the 1950s, business aviation had already existed for decades. However, the market was short on proper business aircraft. The magazine notes that at the time, most business aircraft were converted WWII-era bombers, converted surplus military transports, or a handful of custom-built machines. As Flying Magazine writes, there were some corporate aircraft in development or production, however, they lacked in luxury. The Aero Commander 500 and Beechcraft Queen Air were too small while something like a Twin Beech was slow and didn’t have pressurization.

In other words, the existing aircraft for business were either not really suited for the job of flying executives in comfort, couldn’t really fly high enough to avoid bad weather, or were very expensive to run. For Cessna, this was the prime opportunity to develop an aircraft to haul around 8 to 10 business types in air-conditioned comfort high above those pesky weather systems.

The Cessna 620

Harry Clements worked in Cessna’s Flight Test, Aerodynamics and Preliminary Design group. Over at Air Facts Journal, he detailed what led to and ultimately, what killed the Cessna 620. Clements says that in 1952, an aircraft association conducted a survey to find the ideal aircraft specifications for the day’s business executives. Cessna’s Preliminary Design group then began research to see if those desires could be met and if that ideal plane could be a Cessna. By the end of 1952, the PD group had an early design that met those goals.

Cessna chose to power its business aircraft with four small general aviation engines. These offered greater safety and their nacelles had low drag profiles. The engines promised inexpensive operation for the project. In 1953, Cessna’s PD team were told to continue this research, which involved wind tunnel testing and exploring the avenues that the future aircraft might see a commuter airliner version or a turboprop version.

As Flying Magazine writes, Cessna’s marketing team wanted the 620 to excel in six categories: all-weather capability, comfort, economy, general utility, safety, and speed. Oh and that name? Reportedly, the aircraft was called the 620 because, well, it’s twice the plane the Cessna 310 was.

Out the other end of development, Cessna’s engineers created an aircraft coming in at 15,000 pounds at maximum take off weight and was powered by four 526 cubic inch supercharged Continental GSO-526 air-cooled flat-six engines making 350 HP each. The aircraft had a service ceiling of 25,000 feet, a fuel capacity of 535 gallons, a wingspan of 55 feet, a range of 1,700 miles, and a cruising speed of 260 mph. The Cessna 620 boasted a wide cabin fit for carrying 8 to 10 executives in luxurious comfort. The aircraft even had a Garret turbine auxiliary power unit that pressurized the cabin and provided ground power.

By all accounts, the Cessna 620 was essentially like a commercial airliner but scaled down. Even better, the aircraft could take off from the short fields that make up many general aviation airports. The Cessna 620 made its first flight on August 11, 1956 and it seemed as if the company had a winner on its hands. Test pilots gave the aircraft good marks. Why fly cramped in a small executive aircraft or in a converted bomber when you could hop in this spacious Cessna with six feet of interior height?

An Aircraft That Didn’t Make It

The Cessna 620 seemed like a promising aircraft and to promote it, Cessna took a full-size mockup of the cabin to trade shows and placed it next to existing aircraft. Cessna also had a scale model and technical components on display at shows. Meanwhile, reservation banks were open and Cessna was collecting deposits for the new aircraft. Then, over a year later, Cessna scrapped the program. Just one Cessna 620 would ever be built and the company didn’t even bother preserving it.

The explanation of why this happened seems to vary depending on the source. Flying Magazine points out that the Cessna 620’s price was $375,000 ($4.2 million today). At the time, the Learjet 23 was just five years away and it was $489,000 ($4.9 million today). Flying Magazine notes that while the price difference is still notable, it was perhaps a sign of things to come with jet aviation gaining a foothold with business executives.

Plane & Pilot echoes this idea that perhaps the 620 came just a little too late and that the plane’s competitors might have also included retired piston airliners:

However, the 1950s were the golden age of the jet. During this amazing 10-year period, the “Century Series” jet fighters were designed and constructed, the 707 and DC-8 were born, and the first business jets from Lockheed and North American were just around the corner. Cessna’s Board of Directors realized that these new jets offered speed and altitudes that the Cessna 620 could not match, more than compensating for their smaller and more cramped cabins. They also surmised the transition from props to jets could flood the business aircraft market with older, small piston airliners such as the Martin 404 and the Convair 240. So, even before the single Cessna 620 test article could complete a flight test, the program was canceled, the engines salvaged, and the rest of the airframe destroyed. For those involved in the program, it was a bitter end.

Clements, who worked at Cessna, says that the explanation given was similar to the above, from Air Facts Journal:

The explanation given for the termination of the project was that stated above, that it was likely that because of the growing purchase of jet airliners surplus propeller-driven airline transports like the Convair 240 and Martin 202 (and later versions), which could soon be obtained cheaply as surplus and inexpensively converted to executive configurations, would saturate the market for which the M620 was destined.

Something noted in both Clements’ piece and the Plane & Pilot article is that Cessna’s cancellation of the project apparently created hard feelings. Along the way, it was decided to destroy everything related to the project from the prototype to engineering materials.

Clements argues that the above explanation doesn’t tell the full story. In 1957, there was a recession, which pumped the brakes on expectations. Cessna may have also expected the Lockheed Jetstar and North American Sabreliner jets to have attractive pricing thanks to government subsidies. Cessna also reportedly had a short-term cash flow problem thanks to payments not keeping up with the development of the Cessna T-37 jet trainer. There was also the 620’s cost, which ballooned during development.

Still, Clements concludes that the Cessna 620 could have been successful if it were allowed to live. The aircraft could have had about five years of the business aviation market to itself. And even when competitors like the Beechcraft King Air arrived in the 1960s, the Cessna 620 likely would have remained competitive.

Sadly, that’s something we’ll never know for sure. As I noted before, Cessna went through a lot of work to erase the 620 program and it seems the only surviving bits are photographs. Thankfully, Cessna didn’t give up on this idea and after more development, the manufacturer put the first Citation jet into the sky in 1969. Those jets are popular today, but I still wonder what Cessna’s timeline would have looked like with the 620.

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