The Beechcraft King Air series is the most popular turboprop airplane of all time, according to the National Air & Space Museum. And really, it was way ahead of its time. The first King Airs graced the mid western skies in 1963, and have lived up to their name as the King ever since. Recall the King Air was designed at a time when pistons reigned supreme. In fact, the original 90-series King Air was a derivative of their sleek and graceful Queen Air. The crazy thing for us aviation nerds is that the Queen Air was derived from the Twin Bonanza. So, the King Air shares a direct bloodline with the beloved V-tail itself!

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Now, let’s take a look at this fine aircraft and many (though not all) of the branches on the C-12 tree!

A C-12 Huron lands at an airbase for its formal training unit.
The C-12 Huron formal training unit.

C-12 Huron History: A Beechcraft King Air Primer

Since the C-12 is (or at least began) as an off-the-shelf Super King Air, it’s best to start with the history of the King Air. To understand where the C-12 Huron program is today, we need to start all the way back at the founding of Beechcraft, covering in the process:

  • Walter H. Beech’s company development of the King Air
  • Spec upgrades, from the Queen Air to the King Air
  • King Air’s impact on the C-12 Huron

The Earliest Days of the Beechcraft King Air

Walter H. Beech, founder of Beech Aircraft Company (later rebranded “Beechcraft”), exhibited early signs of aviation prowess. At the age of 14, Beech was designing and building aircraft on his family’s Tennessee farm. He would pursue his passion for flight into the Army Air Corps, piloting DH-4 Libertys during World War I. Before he turned 35, Beech founded his own aerospace company, Travel Air Manufacturing.

It wouldn’t last, though. Within 5 years, Travel Air was purchased by Curtiss-Wright Airplane Company, and Beech found himself in the C-suite rather than overseeing aircraft design and production. He stepped down from his role as president of Curtiss-Wright, opting instead to found another aerospace company: Beechcraft.

Walter H. Beech wouldn’t live to see the creation of the King Air; he died in 1950. Still, his aerospace knowledge and inventiveness propelled Beechcraft to the forefront of aircraft innovation. Beech’s wife and business partner, Olivia Ann Mellor, oversaw the build of the King Air’s predecessor, the Queen Air. 

The Queen Air, a twin-engined monoplane, operated via six-cylinder piston engine. The aircraft was a success, but Beechcraft wasn’t satisfied. After producing both piston and jet engine planes, Beechcraft delivered “the world’s most popular turboprop:” the King Air.

The first King Air model, the King Air 90, skyrocketed to the best selling turboprop within two years of its introduction, outselling all other turboprop aircraft combined. Its initial sales exceeded $10 million within the first 3 months, cementing the King Air 90 as the exemplary turboprop.

King Air’s Specs Improve on the Queen Air

Back to the Queen Air. While it is a beautiful aircraft with sleek lines, it would always be hampered by piston engines. Powered by a pair of 480-cubic-inch Lycomings, the Queen Air produced about 720 horsepower combined. The thing about pistons is that you will tack on additional mass with any increase in output. Mass=weight.

Turbine engines are the answer. Even the first-generation King Air, using the PT-6A, increased output by 210 horsepower per side! And the best part? The PT-6A only weighs 327 lbs.! In contrast, the Lycoming O-480 of the Queen Air has a 498 lb. dry weight. So, it weighs 171 lbs. more than the PT-6A but produces 210 less horsepower.

The other key advantage of turbine engines is their incredible reliability and time between overhauls (TBO). The PT6A is in a 3,500 TBO engine, which is about 1,500 hours longer than most pistons. Turbines also have about ~90% fewer moving parts, making for a smooth and reliable power source. And that takes us to the world’s most popular turboprop.

From the King Air to the C-12 Huron

While no longer at the top of the list of best-selling turboprops, King Air is still a sought-after aircraft. Its three main operating series of planes are:

  1. King Air 90s: These planes represent the entry-level turboprop for owner-pilots. Their shorter length, passenger capabilities, and T-tail model design have persisted since the ‘60s model, proving that quality production lasts.
  2. King Air 200s: The 200 series is the more versatile frame in Beechcraft’s roster, capable of serving business, cargo, and special missions demands. The series includes the Beechcraft King Air 200, 250, 260, and B200GT.
  3. King Air 300s: Succeeding the popular 200s, the Super King Air experienced pushback due to its maximum take-off weight (MTOW) exceeding 12,500 pounds. More 300 series aircraft were introduced, such as the 300LW, B300, and 350i, to provide technological and military upgrades. 

Beechcraft used the Super King Air series as a base to model its C-12 Huron. Rather than seek commercial or business versatility, Beechcraft built its C-12 for military designation. Today, C-12 variants are deployed by the:

  • U.S. Air Force
  • U.S. Army
  • U.S. Marine Corps
  • U.S. Navy

The first C-12 Huron was introduced into military service in 1974 through the U.S. Army, used for personnel transport more than ISR or combat. 

As the C-12 crossed over into wider military applications, the Air Force and Army started outfitting the aircraft with ISR and SIGINT technology. Military variations of the C-12 Huron include: 

“The World’s Most Popular Turboprop”

All in all, over 3,100 King Airs have been manufactured since the first 90-series rolled off the factory floor in 1964. Since then, there have been modifications and models too numerous to mention. But, not only is the King the most popular turboprop, it’s also the OG. A big part of staying on top is starting on top and never letting off the gas.

A white C-12 Huron sits on a runway strip at dusk.
The C-12 Huron originated from the "world's most popular turboprop."

Figure 1"120612-F-ZB796-001" by Joint Base Elmendorf-Richardson is licensed under CC BY-ND 2.0.

The biggest change in advancement in the King Air line was the transition from a low-tail to a T-tail, accompanied by higher output engines (PT6A-41 at 850 shp, up 300 hp from the first iteration of King Airs) and more fuel to feed the thirsty engines. Since it could fly higher with the increased output, the cabin was also pressurized for higher altitudes.

C-12 Huron: Military Lineage and Adoption

Interestingly enough, the first three prototypes of the Super King Air series were delivered to the U.S. Army in 1972.

The Army took an early interest in the King Air, which is no surprise; they were still operating the same piston-powered aircraft as civilians. The Army was the most prolific user of the King Airs, although oddly enough, they picked up unpressurized Model 87s, giving them the designation of U-21 Ute. The Army purchased about 140 Utes total, using them for various utility chores. The Navy also picked up a bunch of H-90s, naming them the T-44A Pegasus, which are still used extensively at NAS Corpus Christi for advanced training.

Special military variants of the C-12, specifically the RC-12 Guardrail, improved military operations with a focus on SIGINT. The variants include:

  • RC-12K
  • RC-12N
  • RC-12P
  • RC-12Q
  • RC-12X/X+


Introduced in 1985, the RC-12K featured stronger engines to increase its MTOW. The aircraft served to intercept comms between enemy combatants. A total of 11 were produced, 9 of which flew for the U.S. Army.


The RC-12N was the first edition to be fitted with Guardrail Common Sensor (GRCS) System functionality. This military variation featured four-bladed propellers, 1,200 shp, and a MTOW over 16,000 pounds.C-12F models were converted to RC-12N. 


With similar specs to the RC-12N, the RC-12P featured improved SIGINT capabilities through upgraded GRCS System 2. 9 RC-12Ps were requisitioned for military use.


RC-12Q Guardrail models featured many of the same specs as the RC-12N and RC-12P—including the GRCS System 2—but it improved on SIGINT through its satellite comms antenna in the dorsal radome. 


The newest model of the RC-12 Guardrail, RC-12X/X+ models are fitted with the most advanced GRCS System in use today. Introduced into the U.S. Army in early 2011, 14 RC-12X/X+s are deployed by our military to perform advanced SIGINT and ISR work. The GRCS economic useful life for RC-12X/X+ model was recently extended to 2034.

Beechcraft Super King Air 200-Based Models

A white Beechcraft uper King Air200 prepares for takeoff as a helicopter hovers in the background
The Beechcraft Super King Air 200 remains in production today.

Released in the 1970s, the Super King Airs are much more capable machines than the 90- and 100-series aircraft. That’s not a dig on the early models; hundreds of them are in service worldwide today. But they lack the range, capacity, and payload of the Supers.

The 200-series is the original Super King Air series and has had a heck of a good run. In fact, the 200-series remains in production to this day. The 200 ended up being almost four feet longer than the A100,which was the production King Air model at the time. Overall shaft horsepower output was increased from 680 shp to 850 shp. Now, think about that: pilots had 980 additional horsepower to work with for an airplane that was a little larger than the Queen Air. Total gamechanger.  

The 200 series C-12s can be divided into two groupings:

  1. C-12A/C/D
  2. C-12F/R/T/U


These initial C-12s were and continue to be the backbone of the fixed-wing Army fleet. The majority of the C-12 fleet is a200 and will be for a long time from now. Pilots in the training pipeline now will probably retire, still flying C-12s. The original C-12A was based on theA200, using the 750shp PT6A-38. The original order was sixty aircraft, and the fleet was upgraded to the C-12C, or “Charlie,” designation as technology advanced. All this meant was that the engines were upgraded to PT6A-41s, which added 100 shp to each side.

The Delta model is still a common sight in Army aviation circles. While it shares the same power plant as the Charlie, the Delta was equipped with a large cargo door for full-size pallets. Since it was pulling double-duty, the crew and passenger entry door is actually inside of the cargo door.


C-12Fs (Foxtrots) marked a major technological leap for the Huron brand. These were the first C-12s produced with four-blade props. The Romeo, Tango, and Uniform models are all derivatives of the Foxtrot, using the PT6A-42. The main difference in these models is generally cockpit modernization initiatives.  

Beechcraft Super King Air 350-Based Models

A gray Beechcraft Super King Air350 sits in a large warehouse
The Beechcraft Super King Air 350 provides cargo support to the U.S. Army.

The Army uses only the Super King Air 350-series cargo version, and that’s the C-12S.

The C-12S provides additional seating for up to 15, with a cabin stretched almost three feet longer than the 300-series and longer wingspan and winglets. The C-12S also is equipped with a cargo door and can be converted for cargo quickly.

The Government Procurement Advantage

It takes a lot of work and a reliable supply chain to keep a fleet of Hurons in the air. Whether it is routine line maintenance, phase/isochronal inspections, or depot-level repairs, you need to know that your parts will be there when you need them. Government Procurement, operated by Greenwood Aerospace, ensures that your focus is on the work that needs to be done, not wondering where the parts are.

We provide a suite of parts kitting and fulfillment services to simplify your operation. We can assemble multiple products from multiple vendors into a comprehensive maintenance kit tailored to your exact airframe and specific tasks. We conform to AS9120B standards to ensure you receive the quality parts and services you need to get your fleet out of the hangar and into the air.

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