The MD Helicopters MD 600N is a light utility civilian helicopter designed in the United States. It is a stretched eight-seat development of the five-seat MD 520N helicopter.
McDonnell Douglas Helicopter Systems (MD Helicopters since 1999) first announced it was developing a stretched MD 520N in late 1994, at that time designated the MD 630N.[1] The prototype, a modified MD 530F, had made its first flight on November 22, 1994. McDonnell Douglas gave the go-ahead for the production aircraft, redesignated the MD 600N, in March 1995.
McDonnell Douglas stretched the MD 520N fuselage by inserting a plug aft of the cockpit/cabin bulkhead and stretching the NOTAR tail boom. The larger fuselage allows for an extra (middle) row of seats. Other differences compared with the MD 520N include a new six blade main rotor (the MD 520N has a five blade unit) and an uprated Allison (now Rolls-Royce) Model 250 turboshaft.
The prototype was modified to MD 600N standard with a production standard engine and tail boom and flew in November 1995, followed the next month by the first MD 600N production prototype.[1] Certification was awarded on May 15, 1997, and deliveries began that June.
Following the 1997 Boeing/McDonnell Douglas' merger, Boeing sold the former MD civil helicopter lines to Netherlands-based RDM Holdings in early 1999.[1]
On March 8, 2017, MD Helicopters unveiled a concept variant known as the MD 6XX.[2] Unlike the MD 600, the MD 6XX utilizes a traditional tail rotor and shares its T-tail design with the smaller MD 500/530F. It is currently in development, with certification originally expected in 2020.[3] However, certification has been delayed indefinitely.[4]