The Robinson R44 is a four-seat light helicopter produced by Robinson Helicopter Company since 1992. Based on the company's two-seat Robinson R22, the R44 features hydraulically assisted flight controls. It was first flown on 31 March 1990 and received FAA certification in December 1992, with the first delivery in February 1993. The R44 has been the world's best-selling general aviation (GA) helicopter every year since 1999. It is one of the most-produced GA aircraft of the 21st century, with 5,941 deliveries from 2001 to 2020. Design The R44 is a single-engined helicopter with a semi-rigid two-bladed main rotor, a two-bladed tail rotor and a skid landing gear. It has an enclosed cabin with two rows of side-by-side seating for a pilot and three passengers. Tail rotor direction of rotation on the R44 is reversed compared to the R22 for improved yaw control authority. On the R44 the advancing blade is on the bottom. Development Designed during the 1980s by Frank Robinson and his staff of engineers, the R44 first flew on 31 March 1990. The R44 Astro was awarded an FAA Type Certificate in December 1992, with the first deliveries taking place in January 1993. The first R44 Newscopter featuring onboard electronic news gathering equipment was delivered in 1998. In January 2000, Robinson introduced the Raven with hydraulically assisted controls and adjustable pedals. In July 2002, Robinson introduced the Raven II featuring a more powerful, fuel-injected engine and wider blades, allowing a higher gross weight and improved altitude performance. During November 2015 Robinson announced the Cadet, a Raven I with a cargo area instead of the two back seats, a slightly less powerful engine and a more efficient muffler. Robinson has carried out ground run testing with an aircraft diesel engine that could replace its Lycoming IO-540 avgas engine. The diesel could provide better altitude performance, a fuel burn reduced from per hour and better fuel availability. Operational history In 1997, a Robinson R44 was piloted by Jennifer Murray for the first helicopter circumnavigation of the world by a woman, covering a distance of 36,000 miles in 97 days. , an R44 holds the piston speed record of 227 km/h. Operators Civilian operators The aircraft is operated by many private individuals, companies and flying clubs. It is also a popular choice for law enforcement agencies. Military and government operators Bolivian Air Force Dominican Republic Army Estonian Air Force Royal Jordanian