Sixty years ago, on Jan. 20, 1964, Beech Aircraft Corporation pilots flew the first official flight of the conforming prototype of the Beechcraft King Air Model 90. Thousands of spectators – from employees to area residents and local and state dignitaries – watched as the aircraft took off from Beech Field on the east side of Wichita, Kansas.
That aircraft and four others took part in an accelerated flight test program. The King Air achieved type certification from the Federal Aviation Administration (FAA) four months later on May 27. In July, one of the five flight test aircraft became the first King Air Model 90 delivered to a corporate owner. Company president Olive Ann Beech personally handed over the keys to John MacNeil, chief pilot for United Aircraft of Canada Ltd. flight operations, the precursor to Pratt & Whitney Canada that had shipped its first production PT6 engines in December 1963, making the new airplane possible.
It was a celebratory, whirlwind start to what would evolve into a royal family of turboprop-powered, cabin-class airplanes. More than 7,700 King Air models have been delivered to customers around the globe, making it the best-selling business turboprop family in the world. The fleet has surpassed 64 million flight hours over six decades, with King Airs being flown by individuals, serving corporate and special mission roles, as well as flying for all branches of the U.S. military.
When Textron Aviation, the current manufacturer of Beechcraft products, announced in 2021 it had ceased production of the King Air C90GTx, a version of the 90-series had been manufactured for 57 years. The factory in Wichita continues to produce three variants: the King Air 260, King Air 360 and King Air 360ER.
To commemorate the King Air’s 60th anniversary, we’re sharing some historic photographs as well as a portion of aviation historian Ed Phillips’ account of the arrival of the legendary turboprop. This article by Ed, a former Beechcrafter who has published eight books on aviation history, was first published in 2011.
The King Arrives
In 1961 Olive Ann Beech listened intently to her loyal corps of vice presidents and engineers as they advocated a bold, new step for the company. …
It centered on marrying the proven and robust airframe of the Model 80 series Queen Air with the gas turbine power of Pratt & Whitney’s new, innovative PT6A turboprop engine. The PT6 was a major design and technical breakthrough in gas turbine technology that promised to deliver significantly more power than was available using reciprocating engines. Although highly reliable, the large displacement, turbocharged engines built by Continental and Lycoming would remain in demand for years to come; they were approaching the limit of their development in terms of horsepower. The New England-based company’s compact, lightweight and powerful PT6A was among the earliest turboprop engines developed specifically for the general aviation segment (which included business aircraft) and delivered 550 shaft horsepower (shp) for takeoff and 500 shp for continuous operation. In addition, it could deliver more than 1,000 pound-feet of torque to the propeller via a simple, reliable planetary-type reduction gearbox.
Although development of turbojet engines had begun in the late 1930s, accelerated quickly during World War II and continued into the 1950s, the focus of engine manufacturers was primarily tied to military and commercial airframes, not business aviation. With the advent of the PT6A, however, gas turbine technology that was forged in the “Jet Age” was finally beginning to “trickle down” to the general aviation market. As far as Beechcraft’s senior engineers were concerned, the Queen Air airframe was a logical match for Pratt & Whitney’s powerplant. All that remained was to convince Olive Ann Beech. After a thorough investigation of the facts and input from her officials, she gave a green light to what would become known as “Project King Air.”
Originally conceived in 1961 as the 300-mph Beechcraft Model 120, the new airplane was officially introduced on July 14, 1963, and made its first flight on January 20, 1964. The company’s engineering department had grafted the PT6A onto the Queen Air airframe, which had been modified to allow the cabin and cockpit to be pressurized to 3.4 psid (pounds per square inch differential). Pressurization was not new in aviation, having been developed late in the 1930s and employed successfully on airplanes such as Boeing’s Model 307 Stratoliner airline transport. But in 1963, it was a novel concept for a small business airplane designed to carry four to six passengers and two pilots, yet the engineers and Beechcraft marketing officials believed it would put the company far ahead of the competition – exactly where Olive Ann Beech wanted it to be.
It should be mentioned that the first airplane built with PT6A engines, designated as the Model 87 and carrying serial number LG-1, had been undergoing rigorous flight tests at the Wichita, Kansas, factory since May 1963. Throughout the airplane’s nearly 10 months of intensive testing, company engineers gradually worked out the inevitable “bugs” associated with any new design, especially one that represented a major leap in technology involving not only an entirely new type of engine, but also a highly modified airframe that came with its own set of unique challenges from the pressurization system.
Designated NU-8F by the Army, the airplane was delivered to Fort Rucker, Alabama, in March 1964 when it began an in-depth evaluation by Army pilots, maintenance officers and mechanics. Prompted in part by the service’s success with the L-23F, of which 71 examples were delivered from 1960-1963, the Army brass wanted an opportunity to take a hard and long look at Beech Aircraft’s latest creation and investigate its potential for military service.
Meanwhile, back in Wichita, preparations were underway to begin production of the Model 90 King Air. With a wingspan of 45 feet, 10.5 inches; a length of 35 feet, six inches and a height of 14 feet, 2.5 inches to the top of its swept vertical stabilizer, the Model 90 had a maximum gross weight of 9,300 pounds and a fuel capacity of 122 gallons of jet fuel carried in nacelle-mounted tanks with another 262 gallons in wing tanks. Three-blade, constant-speed, full-feathering propellers were standard equipment (early production aircraft were not fitted with reversible propellers).
By comparison with current pressurization systems that are fully automatic and often digitally controlled “set-and-forget” installations, the Model 90 had to make do with a single, mechanical Roots-type supercharger mounted in the left nacelle that supplied adequate airflow to inflate the passenger compartment. The primary reason for this necessity centered on the PT6A engine that, in its early configuration, did not have sufficient capability to produce rated power and “spare” enough bleed air from the compressor section to pressurize the cabin – a less than desirable situation that was remedied with more powerful versions of the engine. A pressure relief valve was set to vent cabin air overboard if pressurization exceeded 4.0 psid.
In terms of performance, the Model 90 increased cruise speeds to nearly 300 mph and the Beechcraft marketing department lost no time in espousing the many virtues of the King Air. As aviation pioneer Clyde V. Cessna once said, “Speed is the only reason for flying,” and customers were soon selling or trading in their venerable Model 18s or Queen Airs for the ultra-modern, 280-mph King Air. The airplane was enthusiastically embraced by every corporation and company that took delivery of the “jet prop” executive transport. Pilots long accustomed to managing piston engines had to learn how to handle the PT6A-6 powerplant as well as the pressurization system. They were, however, soon singing the praises of the Model 90’s quiet cabin, fuel-efficient engines, ease of handling and its superior climb and cruise performance compared with the Queen Air or competitor’s airplanes.
The company produced 112 Model 90 King Airs from 1964-1966 when production switched to the upgraded Model A90 that first flew on November 5, 1965. …
With the introduction of the King Air, Olive Ann Beech and the Beech Aircraft Corporation launched business aviation into the “Jet Age” and set yet another standard for the industry to follow. The highly popular King Air series, however, was only beginning to flex its sales muscle and the years ahead would witness development and introduction of an entire “royal family” of turboprop-powered, cabin-class airplanes that served with distinction in both the corporate and military marketplace.
There is still a strong market for King Air models produced in the past and those in production today, and it doesn’t look like it will be slowing down anytime soon.
Long live the King Air!