Eurocopter/Kawasaki BK 117

The BK 117 was developed under a joint collaborative effort between MBB of Germany (now part of Eurocopter) and Kawasaki of Japan, resulting in production lines in both countries. The BK 117 program replaced the independently developed BO 107 and Kawasaki KH7 design studies. The BK 117 retains the former's overall configuration, with Eurocopter responsible for the helicopter's rotor system (which uses a scaled up version of the BO 105's four blade rigid main rotor), tail unit, hydraulic system and power controls, while Kawasaki has responsibility for the fuselage, transmission and undercarriage. Development led to the BK 117's first flight on June 13 1979, the first production aircraft (built in Japan) flew December 1981, certification was awarded in December 1982, and first deliveries took place early in 1983. Initial production was of the BK 117 A1, while the BK 117 A3 with higher max takeoff weight and enlarged tail rotor with twisted blades was certificated in March 1985. The BK 117 A4 introduced from 1987 features increased performance through an increased transmission limit at takeoff power, improved tail rotor head and, on German built aircraft, increased fuel. The BK 117 B1 (certificated in 1987) has more powerful engines and better performance, the BK 117 B2 is currently in production and has an increased max takeoff weight. The BK 117 C1 is a German development with Turboméca Arriel engines, while the BK 117 C-2 now underdevelopment features improvements from the EC 135 including new avionics.

The backbone of this section is from the The International Directory of Civil Aircraft by Gerard Frawley and used with permission. To get your own copy of the book click here.