On 25 February 1977, MBB and Kawasaki signed a cooperative agreement to abandon their independent efforts to design twin-engined general purpose helicopters in favour of a collaborative venture to development of a new rotorcraft for that role.

It is also used for a diverse range of operations, such as aerial crane and sling work, law enforcement, and military transport, and is exceptional as an air ambulance and search and rescue platform.

[1] This helicopter, which proved to be a commercial success, had made use of a revolutionary hingeless main rotor composed of fibreglass, which was developed by German engineer Ludwig Bölkow.

Having established a reputation for reliability and safety, during the early 1970s MBB, along with one of its major shareholders, Boeing Vertol, began studying options for producing an enlarged derivative of the type to accompany the Bo 105.

Under the terms of this agreement, the two corporations merged their previously separate projects to produce twin-engined general purpose helicopters, these being the Bo 107 by MBB and the KH-7 from Kawasaki.

[5] As per their agreement, each company established their own final assembly line for the type, on which they would produce the rotorcraft to meet demands within their respective local markets.

During 1992, the BK 117C-1, equipped with a revised EFIS panel and an improved environmental control system, along with greater hot-and-high performance, was introduced to service.

As promoted, this variant would have been capable of being armed with launchers for eight Euromissile HOT 2 missiles and a chin-mounted Lucas-built turret for a Browning 12.7mm machine gun, aimed using a helmet-mounted sight.

It possessed several attributes that lend itself to performing many different roles, such as twin-engine redundancy, sizable clamshell-shaped rear-facing double doors, and a relatively spacious cabin; one mission to which it was deemed to be suitable was the emergency medical services (EMS).

[10] The airframe is composed of rivetted metal, making minimal use of composite materials, in order to free up internal space, both the engines and transmission are positioned above the main cabin.

[3] Power management has been greatly eased via the addition of an automatic engine-governor system, allowing pilots to simply monitor the torque and engine temperature gauges.

[3] According to aviation publication Flying, as a consequence of its uncommon rigid main rotor system, the BK 117 possessed relatively high stability and manoeuvrability which, amongst other capabilities, reportedly gave the type the ability to perform a steeper approach than any other helicopter in its class.

[12] In terms of its flight performance, the type was considered to be suitable for the execution of various aerobatic manoeuvres, such as flying loops and rolls, while retaining such levels of inherent stability that pilots could readily release both the cyclic and collective controls, unlike the majority of rotorcraft.