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The MBB/Kawasaki BK 117 is a twin-engined light
utility In economics, utility is a measure of a certain person's satisfaction from a certain state of the world. Over time, the term has been used with at least two meanings. * In a normative context, utility refers to a goal or objective that we wish ...
transport helicopter A military transport aircraft, military cargo aircraft or airlifter is a military-owned transport aircraft used to support military operations by airlifting troops and military equipment. Transport aircraft are crucial to maintaining supply ...
. It was jointly developed and manufactured by
Messerschmitt-Bölkow-Blohm Messerschmitt-Bölkow-Blohm (MBB) was a West Germany, West German aerospace manufacturer. It was formed during the late 1960s as the result of efforts to consolidate the West German aerospace industry; aircraft manufacturer Messerschmitt AG merged ...
(MBB) of
Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...
and Kawasaki of
Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...
. MBB was later purchased by
Daimler-Benz Mercedes-Benz Group AG (formerly Daimler-Benz, DaimlerChrysler, and Daimler) is a Germany, German Multinational corporation, multinational Automotive industry, automotive company headquartered in Stuttgart, Baden-Württemberg, Germany. It is o ...
and eventually became a part of
Eurocopter Airbus Helicopters SAS (formerly Eurocopter S.A., trade name, trading as Eurocopter Group) is the helicopter manufacturer, helicopter manufacturing division of Airbus. It is the largest in the industry in terms of revenues and turbine helicopte ...
, which was later rebranded as
Airbus Helicopters Airbus Helicopters SAS (formerly Eurocopter S.A., trading as Eurocopter Group) is the helicopter manufacturing division of Airbus. It is the largest in the industry in terms of revenues and turbine helicopter deliveries, holding 48% of the wo ...
. 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. While the programme's costs were shared equally, the workshare was divided into certain areas of the design. MBB utilised their expertise with the rigid rotor system used on the earlier
Bo 105 The Messerschmitt-Bölkow-Blohm Bo 105 is a light, twin-engine, multi-purpose helicopter developed by Bölkow of Ottobrunn, West Germany. It was the first light twin-engine helicopter in the world, and the first rotorcraft that could perform ae ...
to develop the majority of the dynamic systems and flight controls, while Kawasaki focused on the airframe, structural elements, and various other components. On 13 June 1979, MBB's flying prototype conducted its
maiden flight The maiden flight, also known as first flight, of an aircraft is the first occasion on which it leaves the ground under its own power. The same term is also used for the first launch of rockets. In the early days of aviation it could be dange ...
at
Ottobrunn Ottobrunn () is a suburban municipality southeast of Munich, Bavaria, Germany, founded in 1955. Ottobrunn consists of mainly semi-detached and detached houses, as well as extensive garden areas. Ottobrunn is also the German Headquarters of Airbus ...
,
Bavaria Bavaria, officially the Free State of Bavaria, is a States of Germany, state in the southeast of Germany. With an area of , it is the list of German states by area, largest German state by land area, comprising approximately 1/5 of the total l ...
, Germany; months later, it was followed by the Kawasaki prototype at
Gifu is a Cities of Japan, city located in the south-central portion of Gifu Prefecture, Japan, and serves as the prefectural capital. The city has played an important role in Japan's history because of its location in the middle of the country. Durin ...
,
Chūbu region The , Central region, or is a region in the middle of Honshū, Japan's main island. In a wide, classical definition, it encompasses nine prefectures (''ken''): Aichi, Fukui, Gifu, Ishikawa, Nagano, Niigata, Shizuoka, Toyama, and Ya ...
, Japan on 10 August 1979. Each company established their own final assembly line, producing the BK 117 for their respective regions. The BK 117 has proven to be popular for passenger services and VIP-transport, the cabin can be outfitted with various seating configurations, seating between seven and ten passengers. It is also used for a diverse range of operations, such as
aerial crane An aerial crane or flying crane is a helicopter used to lift heavy or awkward loads. As aerial cranes, helicopters carry loads connected to long cables or slings in order to place heavy equipment when other methods are not available or economical ...
and sling work,
law enforcement Law enforcement is the activity of some members of the government or other social institutions who act in an organized manner to enforce the law by investigating, deterring, rehabilitating, or punishing people who violate the rules and norms gove ...
, and
military transport Military supply-chain management is a cross-functional approach to procuring, producing and delivering products and services for military materiel applications. Military supply chain management includes sub-suppliers, suppliers, internal in ...
, and is exceptional as an
air ambulance Air medical services are the use of aircraft, including both fixed-wing aircraft and helicopters to provide various kinds of urgent medical care, especially prehospital, emergency and critical care to patients during aeromedical evacuation an ...
and
search and rescue Search and rescue (SAR) is the search for and provision of aid to people who are in distress or imminent danger. The general field of search and rescue includes many specialty sub-fields, typically determined by the type of terrain the search ...
platform. During the 1990s, due to its popularity, a refined derivative, initially marketed as the BK 117 C-2 before being rebranded as the
EC 145 The Airbus Helicopters H145, formerly the Eurocopter EC145, is a twin-engine light utility helicopter developed and manufactured by Airbus Helicopters. Originally designated as the ''BK 117'', the H145 is based upon the MBB/Kawasaki BK 117 C1 ...
and later as the H145, was developed from the BK 117 C-1 version; this improved version of the rotorcraft has since succeeded the original BK 117 in production. The original BK 117, Eurocopter EC 145, and Airbus Helicopters H145, are typically thought of as being in one design family, despite different marketing and naming.


Development


Origins

According to aviation author J. Mac. McCellan, the BK 117 has its origins in an earlier rotorcraft designed and produced by
German German(s) may refer to: * Germany, the country of the Germans and German things **Germania (Roman era) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizenship in Germany, see also Ge ...
aerospace manufacturer
Messerschmitt-Bölkow-Blohm Messerschmitt-Bölkow-Blohm (MBB) was a West Germany, West German aerospace manufacturer. It was formed during the late 1960s as the result of efforts to consolidate the West German aerospace industry; aircraft manufacturer Messerschmitt AG merged ...
(MBB), the
MBB Bo 105 The Messerschmitt-Bölkow-Blohm Bo 105 is a light, twin-engine, multi-purpose helicopter developed by Bölkow of Ottobrunn, West Germany. It was the first light twin-engine helicopter in the world, and the first rotorcraft that could perform ...
.McCellan 1986, p. 64. This helicopter, which proved to be a commercial success, had made use of a revolutionary
hinge A hinge is a mechanical bearing that connects two solid objects, typically allowing only a limited angle of rotation between them. Two objects connected by an ideal hinge rotate relative to each other about a fixed axis of rotation, with all ...
less main rotor composed of
fibreglass Fiberglass (American English) or fibreglass ( Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass c ...
, which was developed by German engineer
Ludwig Bölkow Ludwig Bölkow (30 June 1912 – 25 July 2003) was one of the aeronautical pioneers of Germany. Background Born in Schwerin, in then north-central Germany, in 1912, Bölkow was the son of a foreman employed by Fokker, one of the leading air ...
. Having established a reputation for reliability and safety, during the early 1970s MBB, along with one of its major
shareholder A shareholder (in the United States often referred to as stockholder) of corporate stock refers to an individual or legal entity (such as another corporation, a body politic, a trust or partnership) that is registered by the corporation as the ...
s,
Boeing Vertol Boeing Rotorcraft Systems (formerly Boeing Helicopters and before that Boeing Vertol) is the former name of an American aircraft manufacturer, now known as Vertical Lift division of Boeing Defense, Space & Security. The headquarters and main r ...
, began studying options for producing an enlarged derivative of the type to accompany the Bo 105.McCellan 1986, pp. 64, 66. However, Boeing soon withdrew from the venture, leading to MBB searching for another partner; this was found in the form of
Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...
ese company
Kawasaki Heavy Industries is a Japanese Public company, public multinational corporation manufacturer of motorcycles, engines, Heavy equipment (construction), heavy equipment, aerospace and Military, defense equipment, rolling stock and ships, headquartered in Minato, To ...
.McCellan 1986, p. 66. On 25 February 1977, MBB and Kawasaki signed an agreement to cooperate on the development of a new rotorcraft. 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.''Air International'' April 1989, p. 163. All of the privately incurred development costs were shared equally between the two partners; in November 1977, the programme received a huge boost when the government of
West Germany West Germany was the common English name for the Federal Republic of Germany (FRG) from its formation on 23 May 1949 until German reunification, its reunification with East Germany on 3 October 1990. It is sometimes known as the Bonn Republi ...
announced that it would fund half of the costs of development."The Market for Light Military Rotorcraft."
''Forecast International'', November 2010.
By April 1978, project definition studies had been completed, enabling the joint venture to proceed with the detail design phase of development. Separate elements of the design were assigned to each company; MBB were responsible for developing the
rotor ROTOR was an elaborate air defence radar system built by the British Government in the early 1950s to counter possible attack by Soviet bombers. To get it operational as quickly as possible, it was initially made up primarily of WWII-era syst ...
s (these were based on the rigid rotor system previously used on MBB's
Bo 105 The Messerschmitt-Bölkow-Blohm Bo 105 is a light, twin-engine, multi-purpose helicopter developed by Bölkow of Ottobrunn, West Germany. It was the first light twin-engine helicopter in the world, and the first rotorcraft that could perform ae ...
), tailboom,
flight control A conventional fixed-wing aircraft flight control system (AFCS) consists of flight control surfaces, the respective cockpit controls, connecting linkages, and the necessary operating mechanisms to control an aircraft's direction in flight. A ...
s and
hydraulic Hydraulics () is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counterpart of pneumatics, which concer ...
system while Kawasaki undertook the development of the
landing gear Landing gear is the undercarriage of an aircraft or spacecraft that is used for taxiing, takeoff or landing. For aircraft, it is generally needed for all three of these. It was also formerly called ''alighting gear'' by some manufacturers, s ...
,
airframe The mechanical structure of an aircraft is known as the airframe. This structure is typically considered to include the fuselage, undercarriage, empennage and wings, and excludes the propulsion system. Airframe design is a field of aeros ...
, main transmission, electrical system and other minor components. German
vehicle A vehicle () is a machine designed for self-propulsion, usually to transport people, cargo, or both. The term "vehicle" typically refers to land vehicles such as human-powered land vehicle, human-powered vehicles (e.g. bicycles, tricycles, velo ...
manufacturer
BMW Bayerische Motoren Werke AG, trading as BMW Group (commonly abbreviated to BMW (), sometimes anglicised as Bavarian Motor Works), is a German multinational manufacturer of vehicles and motorcycles headquartered in Munich, Bavaria, Germany. Th ...
acted as a consultant on the styling of the BK 117. 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.''Air International'' April 1989, p. 164. Originally, each company intended to construct a pair of
prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototype ...
s (in actuality, Kawasaki opted to only build a single prototype) which were to be completed by 1979; one for flight testing purposes and the others for tie down testing and static testing. On 13 June 1979, MBB's flying prototype conducted its
maiden flight The maiden flight, also known as first flight, of an aircraft is the first occasion on which it leaves the ground under its own power. The same term is also used for the first launch of rockets. In the early days of aviation it could be dange ...
at
Ottobrunn Ottobrunn () is a suburban municipality southeast of Munich, Bavaria, Germany, founded in 1955. Ottobrunn consists of mainly semi-detached and detached houses, as well as extensive garden areas. Ottobrunn is also the German Headquarters of Airbus ...
,
Bavaria Bavaria, officially the Free State of Bavaria, is a States of Germany, state in the southeast of Germany. With an area of , it is the list of German states by area, largest German state by land area, comprising approximately 1/5 of the total l ...
, Germany; months later, it was followed by the Kawasaki prototype at
Gifu is a Cities of Japan, city located in the south-central portion of Gifu Prefecture, Japan, and serves as the prefectural capital. The city has played an important role in Japan's history because of its location in the middle of the country. Durin ...
,
Chūbu region The , Central region, or is a region in the middle of Honshū, Japan's main island. In a wide, classical definition, it encompasses nine prefectures (''ken''): Aichi, Fukui, Gifu, Ishikawa, Nagano, Niigata, Shizuoka, Toyama, and Ya ...
, Japan on 10 August 1979. The pace of development on the programme had been slower than expected, a problem that was exacerbated by a shortage of skilled manpower that was available at MBB. Although it was originally planned for the rotorcraft's airworthiness certification to be achieved before the end of 1980, German certification was not achieved until 9 December 1982, being quickly followed by the receipt of Japanese certification on 17 December 1982. On 29 March 1983, the type secured the all-important
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Federal Aviation Administration The Federal Aviation Administration (FAA) is a Federal government of the United States, U.S. federal government agency within the United States Department of Transportation, U.S. Department of Transportation that regulates civil aviation in t ...
(FAA) certification, clearing it for widespread use.''Air International'' April 1989, pp. 164–165.


Further development

During 1983, the initial production version, designated as the ''BK 117A-1'' was first delivered. Improved variants were quickly developed; in early 1985, the ''BK 117A-3'', featuring an increased maximum takeoff weight and an enlarged tail rotor with twisted airfoils, was certified; two years later, the ''BK 117A-4'', equipped with LTS 101-750B-1 engines for improved hot/high performance and increased maximum takeoff weight, along with improvements to the main rotor transmission and tail rotor mast, as well as a larger capacity fuel tank, was introduced. During 1990, MBB's American division launched a dedicated corporate version of the BK 117; it was furnished with a
Honeywell Honeywell International Inc. is an American publicly traded, multinational conglomerate corporation headquartered in Charlotte, North Carolina. It primarily operates in four areas of business: aerospace, building automation, industrial automa ...
-built SPZ-7000 digital automatic
flight control system A conventional fixed-wing aircraft flight control system (AFCS) consists of flight control surfaces, the respective cockpit controls, connecting linkages, and the necessary operating mechanisms to control an aircraft's direction in flight. ...
and a cocoon-type interior system; optional extras included a Bendix/King electronic flight instrumentation system (EFIS) and a clamshell cabin door. 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. At one stage, there was considerable attention paid to the concept of a dedicated militarised variant of the type. During the 1985
Paris Air Show The Paris Air Show (, ''Salon du Bourget'') is a trade fair and air show held in odd years at Paris–Le Bourget Airport in France. Organized by the French aerospace industry's primary representative body, the ''Groupement des industries frança ...
, the concept of an armed
attack helicopter An attack helicopter is an armed helicopter with the primary role of an attack aircraft, with the offensive (military), offensive capability of engaging ground targets such as enemy infantry, military vehicles and fortifications. Due to their ...
derivative, referred to as the ''BK 117A-3M'', was revealed to the general public. As promoted, this variant would have been capable of being armed with launchers for eight
Euromissile Euromissile was a European consortium set up in the 1970s by France's Aérospatiale and West Germany's DASA, DaimlerChrysler Aerospace AG to produce the Euromissile HOT anti-tank missile. On April 5, 1991, Thomson-CSF joined the Euromissile Econ ...
HOT 2 missiles and a chin-mounted
Lucas Lucas or LUCAS may refer to: People * Lucas (surname) * Lucas (given name) Arts and entertainment * Luca Family Singers, or the Lucas, a 19th-century African-American singing group * Lucas, a 1960s Swedish pop group formed by Janne Lucas Perss ...
-built
turret Turret may refer to: * Turret (architecture), a small tower that projects above the wall of a building * Gun turret, a mechanism of a projectile-firing weapon * Optical microscope#Objective turret (revolver or revolving nose piece), Objective turre ...
for a Browning 12.7mm machine gun, aimed using a
helmet-mounted sight A helmet-mounted display (HMD) is a headworn device that uses displays and optics to project imagery and/or symbology to the eyes. It provides visual information to the user where head protection is required – most notably in military aircr ...
. It was also to be equipped with various advanced targeting sensors, including an SFIM APX-M 397 roof-mounted stabilized
sight Visual perception is the ability to detect light and use it to form an image of the surrounding Biophysical environment, environment. Photodetection without image formation is classified as ''light sensing''. In most vertebrates, visual percept ...
. In order to provide sufficient ground clearance for the gun turret, the use of higher skid landing gear would have also been necessitated. During the 1990s, as a result of the commercial success of the type, a refined derivative, initially marketed as the ''BK 117 C-2'' prior to its rebranding as the
EC 145 The Airbus Helicopters H145, formerly the Eurocopter EC145, is a twin-engine light utility helicopter developed and manufactured by Airbus Helicopters. Originally designated as the ''BK 117'', the H145 is based upon the MBB/Kawasaki BK 117 C1 ...
and later as the ''H145'', was developed from the BK 117 C-1 version; this improved version of the rotorcraft has succeeded and eventually replaced the original BK 117 in production. In total, 443 BK 117s were manufactured by the two partners; 329 (and two prototypes) were produced by MBB at their Donauworth facility while 111 (and one prototype) were completed by Kawasaki in Japan. During the 1980s, an agreement was formed with
Indonesian Aerospace Indonesian Aerospace (IAe) (), is an Indonesian aerospace company involved in aircraft design and the development and manufacture of civilian and military regional commuter aircraft, and a subsidiary of state-owned electronics manufacturer . Th ...
, enabling the type to be produced under license in
Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...
, which was accordingly designated as the ''NBK 117''; however, according to economics author Sören Eriksson, the Indonesian production programme was terminated after only a handful of rotorcraft were completed. Since exiting production, third parties have produced their own upgrade programmes for existing BK 117s. In 2010, Airwork launched its conversion programme for the type, replacing the original LTS101-750B-1 engine with the newer LTS101-850B-2 engine, increasing both its performance, reliability and safety margins, resulting in the ''BK117-850D2''; by 2016, Airwork had upgraded nearly 50 rotorcraft in this manner.


Design

The MBB/Kawasaki BK 117 is a twin-engined medium
utility In economics, utility is a measure of a certain person's satisfaction from a certain state of the world. Over time, the term has been used with at least two meanings. * In a normative context, utility refers to a goal or objective that we wish ...
transport helicopter A military transport aircraft, military cargo aircraft or airlifter is a military-owned transport aircraft used to support military operations by airlifting troops and military equipment. Transport aircraft are crucial to maintaining supply ...
. 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 Emergency medical services (EMS), also known as ambulance services, pre-hospital care or paramedic services, are emergency services that provide urgent pre-hospital treatment and stabilisation for serious illness and injuries and transport to d ...
(EMS).McCellan 1986, p. 62, 64. The airframe is composed of
rivet A rivet is a permanent mechanical fastener. Before being installed, a rivet consists of a smooth cylinder (geometry), cylindrical shaft with a head on one end. The end opposite the head is called the ''tail''. On installation, the deformed e ...
ted metal, making minimal use of
composite Composite or compositing may refer to: Materials * Composite material, a material that is made from several different substances ** Metal matrix composite, composed of metal and other parts ** Cermet, a composite of ceramic and metallic material ...
materials, in order to free up internal space, both the engines and transmission are positioned above the main cabin. Considerable efforts were made to reduce the weight of the aircraft where possible albeit without compromising the aircraft's structural integrity. The cabin could be configured with various interiors in order to suit its purpose. Early versions of the BK 117 were powered by a pair of
Lycoming LTS101 The Lycoming (now Honeywell) LTS101 is a turboshaft engine family ranging from 650 to 850 shaft horsepower, used in a number of popular helicopters, and, as the LTP101 turboprop, light aircraft. Both models carry the US military designation T702 ...
turboshaft A turboshaft engine is a form of gas turbine that is optimized to produce shaft horsepower rather than jet thrust. In concept, turboshaft engines are very similar to turbojets, with additional turbine expansion to extract heat energy from the ex ...
engines, rated to generate 550 shp at takeoff with considerable reserve power to guard against a single engine failure. While each engine possesses sufficient power to maintain flight and even takeoff in the event of a single engine being rendered inoperable, the type also has favourable
autorotation Autorotation is a state of flight in which the main rotor system of a helicopter or other rotary-wing aircraft turns by the action of air moving up through the rotor, as with an autogyro, rather than engine power driving the rotor. Bensen, Igor ...
capabilities. In order to extend their operational lifespan and increase their reliability, MBB tuned the engines to operate at lower-than-standard
revolutions per minute Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or r⋅min−1) is a unit of rotational speed (or rotational frequency) for rotating machines. One revolution per minute is equivalent to hertz. Standards ISO 80000-3:2019 de ...
(RPM).McCellan 1986, pp. 66–67. The engines are regulated using a specialised control system which smoothly and evenly regulate RPM and
torque In physics and mechanics, torque is the rotational analogue of linear force. It is also referred to as the moment of force (also abbreviated to moment). The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. Wh ...
between both engines, even during vigorous manoeuvers. Power management has been greatly eased via the addition of an automatic engine-
governor A governor is an politician, administrative leader and head of a polity or Region#Political regions, political region, in some cases, such as governor-general, governors-general, as the head of a state's official representative. Depending on the ...
system, allowing pilots to simply monitor the torque and engine temperature gauges. The aircraft can be suitably equipped for flight under
instrument flight rules In aviation, instrument flight rules (IFR) is one of two sets of regulations governing all aspects of civil aviation aircraft operations; the other is visual flight rules (VFR). The U.S. Federal Aviation Administration's (FAA) ''Instrument Fl ...
(IFR) as well as for single-pilot operations. According to aviation publication ''Flying'', as a consequence of its uncommon rigid main
rotor ROTOR was an elaborate air defence radar system built by the British Government in the early 1950s to counter possible attack by Soviet bombers. To get it operational as quickly as possible, it was initially made up primarily of WWII-era syst ...
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. The four-bladed main rotor was smaller and slower-turning than many of its contemporaries, reducing both vibration and noise while also enabling the type to use more compact landing sites. The high-mounted tail boom and tail rotor of the BK 117 also presented several benefits, such as enhanced safety to personnel on the ground.McCellan 1986, p. 67. In terms of its flight performance, the type was considered to be suitable for the execution of various
aerobatic Aerobatics is the practice of flying maneuvers involving aircraft attitudes that are not used in conventional passenger-carrying flights. The term is a portmanteau of "aeroplane" and "acrobatics". Aerobatics are performed in aeroplanes and gl ...
manoeuvres, such as flying loops and rolls, while retaining such levels of inherent stability that pilots could readily release both the
cyclic Cycle, cycles, or cyclic may refer to: Anthropology and social sciences * Cyclic history, a theory of history * Cyclical theory, a theory of American political history associated with Arthur Schlesinger, Sr. * Social cycle, various cycles in s ...
and
collective A collective is a group of entities that share or are motivated by at least one common issue or interest or work together to achieve a common objective. Collectives can differ from cooperatives in that they are not necessarily focused upon an e ...
controls, unlike the majority of rotorcraft. An optional
Sperry Sperry may refer to: Places In the United States: * Sperry, Iowa, community in Des Moines County * Sperry, Missouri *Sperry, Oklahoma, town in Tulsa County * Sperry Chalet, historic backcountry chalet, Glacier National Park, Montana * Sperry Glaci ...
-built three-axis stability augmentation system also served to improve the rotorcraft's ease of handling.


Operational history

A single BK 117 A-3 (c/n 7106) was leased by the
Canadian Forces Air Command The Royal Canadian Air Force (RCAF; ) is the air force, air and space force of Canada. Its role is to "provide the Canadian Forces with relevant, responsive and effective airpower". The RCAF is one of three environmental commands within the un ...
for a test program and designated as the CH-143. When the program was over, the aircraft was returned to MBB Canada. A BK 117 helicopter contracted by the
New South Wales Rural Fire Service The New South Wales Rural Fire Service (NSW RFS) is a volunteer-based firefighting government agency, agency and statutory body of the Government of New South Wales. The NSW RFS is responsible for fire protection to approximately 95% of the la ...
to fight fires crashed on 17 August 2018, the pilot died in the crash.


Variants

;BK 117 P-2 (D-HBKA):German prototype, first flown 13 June 1979. Now exhibited at the Bückeburg helicopter museum, Bückeburg, Germany. ;BK 117 S-01 (D-HDRF):Initial pre-production prototype. Now preserved on top of the DRF-Headquarters at Stuttgart Airport. ;BK 117 P-3/P-5 (JQ0003):Japanese prototype, first flown 10 August 1979. Now exhibited at Kakamigahara Aerospace Museum, Kakamigahara/Gifu, Japan ;BK 117 A-1 :Powered by two Lycoming LTS 101-650B-1 engines. First flown 23 April 1982. ;BK 117 A-3 :Introduced in March 1985, the A-3 has a larger tail rotor with improved blades, Yaw CSAS, improved stability (SPAS) and the take-off weight increased to 3,200 kg (7,055 lb).- The Canadian Armed forces leased a single BK 117-A3 for a test program and designated it the CH-143. When the program was over, the aircraft was returned to MBB Canada ;BK 117 A-4 :Introduced in July 1986, the A-4 has increased transmission limits at take-off power, improved tail rotor head. German aircraft have provision for extra internal fuel, giving enhanced performance. ;BK 117 A-3M :Military version introduced in 1986. The A-3M is fitted with taller skids and can carry 11 troops. A Browning 12.7 mm (0.5 in) machine gun can be mounted under the fuselage in a Lucas turret with 450 rounds and controlled by a helmet-mounted sight. The A-3M also has outrigger pylons which can hold up to eight HOT II or TOW antitank missiles or a variety of air-to-air missiles, rocket-pods, or forward-firing cannons. Provisions for a doorway gunner's position with a 12.7 mm (0.5 in) gun can also be installed. ;BK 117 B-1 :Introduced in December 1987, the B-1 is fitted with LTS 101-750B-1 engines to provide increased performance, and a 140 kg (309 lb) increase in payload. ;BK 117 B-1C :UK-certified version with reduced range and endurance. ;BK 117 B-2 :Maximum Gross Weight increased to 3,350 kg, 2 x Allied Signal Lycoming LTS101-750B-1 engines fitted as standard, new tail rotor blades, improved "hot and high" performance, take-off/landing limitation increased to 15,000 ft, improved flight performance for: HIGE/HOGE, single engine service ceiling. ;BK 117 C-1 :Powered by two
Turbomeca Arriel The Turbomeca Arriel is a series of French turboshaft engines that first ran in 1974.Gunston 1989, p.170. Delivering , over 12,000 Arriel engines have been produced from 1978 to 2018, logging more than 50 million flight hours for 40 helicopter ...
1E engines. Later models may be upgraded to Arriel 1E2 engines. ;NBK 117 :
License-built Licensed production is the production under license of technology developed elsewhere. The licensee provides the licensor of a specific product with legal production rights, technical information, process technology, and any other proprietary compo ...
model produced in Indonesia by
Indonesian Aerospace Indonesian Aerospace (IAe) (), is an Indonesian aerospace company involved in aircraft design and the development and manufacture of civilian and military regional commuter aircraft, and a subsidiary of state-owned electronics manufacturer . Th ...
.The Emerging Technological Trajectory of the Pacific Rim by Denis Fred Simon, page 193. ;BK 117-850D2 :Introduced in 2010, the 850D2 variant is an STC (Supplementary Type Certificate) development (i.e., re-engined) of BK 117 B-2 incorporating Honeywell LTS 101-850B-2 engines aimed at improving OEI and Category A performance. Development and certification was conducted in New Zealand by Airwork of Ardmore, NZ, in conjunction with Flight Structures Ltd. NOTE: All later models are derived from the BK 117 by Eurocopter Deutschland and later Airbus Helicopters.
The models BK 117-C2, -D2 and -D3 are therefore better known under their commercial naming convention EC145 and H145. Nevertheless, all models share the same EASA Type Certificate (see EASA Type Certificate Data Sheet).


Operators


Military and government

; *
Fire and Rescue NSW Fire and Rescue NSW (FRNSW) previously known as NSW Fire Brigades (NSWFB), is a agency of the New South Wales Government, Australia. FRNSW is responsible for firefighting, rescue and HAZMAT services in the major cities, metropolitan areas and ...
(formerly) *
New South Wales Rural Fire Service The New South Wales Rural Fire Service (NSW RFS) is a volunteer-based firefighting government agency, agency and statutory body of the Government of New South Wales. The NSW RFS is responsible for fire protection to approximately 95% of the la ...
*
New South Wales Police Force The New South Wales Police Force is a law enforcement agency of the state of New South Wales, Australia, established in 1862. With more than 17,000 police officers, it is the largest police organisation in Australia, policing an area of 801,60 ...
*
Western Australia Police The Western Australia Police Force, colloquially WAPOL, provides police services throughout the state of Western Australia to a population of 2.66 million people, of which 2.11 million reside in the Perth Metropolitan Region. Western Australia h ...
; *
Chilean Air Force The Chilean Air Force () is the air force of Chile and branch of the Chilean military. History The first step towards the current FACh is taken by Lieutenant Colonel, Teniente Coronel training as a pilot in France. Although a local academy was c ...
*
Carabineros de Chile The () are the Chilean national law enforcement gendarmerie, who have jurisdiction over the entire national territory of the Republic of Chile. Created in 1927, their mission is to maintain order and enforce the laws of Chile. They reported to ...
; *
Colombian National Armada The Colombian Navy, officially the Colombian National Navy (), also known as the ''"Armada Nacional"'' or just the ''"Armada"'' in Spanish, is the naval branch of the military forces of Colombia. The Navy is responsible for security and defence ...
; *
Hellenic Fire Service The Hellenic Fire Service () is the national fire and rescue service of Greece. It is part of the Ministry of Public Order and Citizen Protection (Greece), Ministry for Citizen Protection. Today they are 17% of the strength of the Service. Volunt ...
– Operates three BK-117C1s. ; *
Prefectural police department In the law enforcement system in Japan, are prefecture-level law enforcement agencies responsible for policing, law enforcement, and public security within their respective prefectures of Japan. Although prefectural police are, in principle, re ...
s ; *
Malagasy Air Force The Malagasy Air Force () is the aerial warfare branch of the Madagascar Armed Forces. History The Malagasy Air Force was founded in 1960 with mainly former French aircraft such as Douglas DC-3s, Max Holste MH.1521 Broussards and Dassault MD ...
; *
Peruvian National Police The National Police of Peru (, PNP) is the national police force of Peru. Its jurisdiction covers the nation's land, sea, and air territories. Formed from the merger of the Investigative Police, the Civil Guard, and the Republican Guard in 1988 ...
; * Ministry of Emergency Situations ; *
Guardia Civil The Civil Guard (; ) is one of the two national law enforcement agencies of Spain. As a national gendarmerie, it is military in nature and is responsible for civil policing under the authority of both the Ministry of the Interior and the Minis ...
; *
South African Air Force The South African Air Force (SAAF) is the air warfare branch of South African National Defence Force, with its headquarters in Pretoria. The South African Air Force was established on 1 February 1920. The Air Force saw service in World War II a ...
*
South African Police Service The South African Police Service (SAPS) is the national police force of the Republic of South Africa. Its 1,154 police stations in South Africa are divided according to the Provinces of South Africa, provincial borders, and a Provincial Commis ...
; *
Riverside County Sheriff's Department The Riverside County Sheriff's Department, also known as the Riverside Sheriff's Office (RSO), is a law enforcement agency in Riverside County, in the U.S. state of California. Overseen by an elected Sheriffs in the United States, sheriff-corone ...
(California)


Civil

The majority of the helicopters are operated by various emergency services although it is also operated by private individuals, companies and executive charter operators. ; * CareFlight * Westpac Life Saver Rescue Service ;
Yellowhead Helicopters Ltd.
*
Shock Trauma Air Rescue Society The Shock Trauma Air Rescue Service (STARS, formerly Shock Trauma Air Rescue Society) is a Canadian non-profit helicopter air ambulance organization funded by individual donors, service groups, corporate donors and government contributions. ST ...
* Helico Secours * Airmedic ; * Everett Aviation ; *
Auckland Rescue Helicopter Trust The Auckland Westpac Rescue Helicopter is a New Zealand accident and emergency rescue and transport service operated by Northern Rescue Helicopter Ltd (NRH''. The operator is a joint venture between Northland Emergency Services Trust and Auc ...
*
Life Flight (New Zealand) Life Flight, or Life Flight Trust, is a charitable trust providing an emergency air ambulance and rescue helicopter service that operates out of Wellington, New Zealand. Their services include the Wellington-based BK117 Westpac Rescue Helicopt ...
* Canterbury West Coast Air Rescue Trust *
Otago Rescue Helicopter Trust The Otago Rescue Helicopter trust is an emergency helicopter service covering the lower South Island area of New Zealand, used for accident and medical air ambulance missions, and search and rescue. , the service operates a MBB/Kawasaki BK 117 ...
; *
Rega (air rescue) Swiss Air-Rescue (German: ''Schweizerische Rettungsflugwacht'', French: ''Garde aérienne suisse de sauvetage'', Italian: ''Guardia aerea svizzera di soccorso'', Rega) is a private, non-profit air rescue service that provides emergency medical assi ...
: 7 H145 since 2018, replacing the EC145 ; * Daily Air Corporation ; * Si Chang Flying Services ; *
Air Methods Air Methods Corporation is an American privately owned helicopter operator. The air medical division provides emergency medical services to over 100,000 patients every year. It operates in 48 states with air medical as its primary business focus ...
*
St. Louis Children's Hospital St. Louis Children's Hospital is a dedicated pediatric hospital in St. Louis, Missouri, and has a primary service region covering six states. As the pediatric teaching hospital for Washington University School of Medicine, St. Louis Children's ...
*
Orlando Regional Medical Center Orlando Regional Medical Center (ORMC) is an 808-bed tertiary hospital in downtown Orlando, Florida designed by HKS, Inc. (architect) and Walter P Moore (structural engineer). It is the flagship of the Orlando Health system. Background ORMC is ...


Former

; *
Bophuthatswana Air Force The Bophuthatswana Air Force (BAF) was the aviation branch of the Bophuthatswana Defence Force. The BAF existed from 1987 until 27 April 1994. The primary role of the BAF was to provide support and medevac services to the ground units of the Bophu ...
; *
Canadian Forces Air Command The Royal Canadian Air Force (RCAF; ) is the air force, air and space force of Canada. Its role is to "provide the Canadian Forces with relevant, responsive and effective airpower". The RCAF is one of three environmental commands within the un ...
; *
Ciskei Defence Force The Ciskei Defence Force (CDF) was established during March 1981 from the 141 Battalion of the South African Defence Force (SADF). It was the defence force of Ciskei, a bantustan that was controlled by the apartheid regime of South Africa. The ...
; *
ADAC The ADAC, officially the Allgemeiner Deutscher Automobil-Club (), is Europe's largest automobile association. The ADAC is the largest wikt:Verein, ''verein'' (club) in Germany, with around 21 million members. Its headquarters are located i ...
*
DRF Luftrettung The DRF Luftrettung (formerly ''Deutsche Rettungsflugwacht e.V.)'' is part of the German emergency medical services as a branch of the air medical services. The DRF Luftrettung and its subsidiaries operate in Germany, Austria, and Liechtenstein. ...
*Bundeswehr *German State Police ; *
Transkei Defence Force The Transkei Defence Force (TDF) was established during March 1981, from the 141 Battalion of the South African Defence Force (SADF). It was the defence force of the Republic of Transkei, a nominally independent bantustan during the Apartheid ...
; *
Venda Defence Force The Venda Defence Force (VDF) was established in September 1982 from the 112 Battalion of the South African Defence Force and the military branch of the Venda National Force which itself had been formed when the Venda homeland became independe ...


Specifications (BK 117 B-2)


See also


References


Citations


Bibliography

* "BK 117...a Terrestrial Space Ship". ''
Air International ''AIR International'' is a British aviation magazine covering current defence aerospace and civil aviation topics. It has been in publication since 1971 and is currently published by Key Publishing Ltd. History and profile The magazine was fir ...
'', Vol 36 No 4, April 1989. Bromley, UK:Fine Scroll. . pp. 163–170. * Eriksson, Sören. "Clusters and Economic Growth in Asia." ''Edward Elgar Publishing, 2013. . * Hatch, Paul
"World's Air Forces"
''
Flight International ''Flight International'', formerly ''Flight'', is a monthly magazine focused on aerospace. Published in the United Kingdom and founded in 1909 as "A Journal devoted to the Interests, Practice, and Progress of Aerial Locomotion and Transport", i ...
'', 5–11 December 1990. pp. 35–81. * Hoyle, Craig. "World Air Forces Directory". ''
Flight International ''Flight International'', formerly ''Flight'', is a monthly magazine focused on aerospace. Published in the United Kingdom and founded in 1909 as "A Journal devoted to the Interests, Practice, and Progress of Aerial Locomotion and Transport", i ...
'', Vol. 182, No. 5370, 11–17 December 2012. pp. 40–64. . * Lambert, Mark. ''Jane's All The World's Aircraft 1993–94''. Coulsdon, UK:Jane's Data Division, 1993. . * McCellan, J. Mac
"Paramedic."
''
Flying Flying may refer to: * Flight, the process of flying * Aviation, the creation and operation of aircraft Music Albums * '' Flying (Cody Fry album)'', 2017 * ''Flying'' (Grammatrain album), 1997 * ''Flying'' (Jonathan Fagerlund album), 2008 * ...
'', February 1986. Vol. 113, No. 2. pp. 62–67. . * Mlandenov, Alexander. "Russia's Responders". ''Air International'', Vol. 91, No. 6, December 2016. pp. 78–87. . * Prétat, Samuel
"EC 145 & UH-72."
''Éditions Minimonde76'', 2015. . * Scharenborg, Martin. "Fighting the fires". ''Air International'', Vol. 103 No. 2, September 2022. pp. 68–72. .


External links


Manufacturer's website

BK 117 in aeromedical services

BK 117 factsheet
{{DEFAULTSORT:Mbb Kawasaki Bk 117 BK 117, MBB Kawasaki 1970s German helicopters 1970s international civil utility aircraft BK 117, MBB Kawasaki BK 117, MBB Kawasaki 1970s Japanese helicopters Twin-turbine helicopters Aircraft first flown in 1979 Germany–Japan relations