Kawasaki Heavy Industries Aerospace Company
Encyclopedia
is the aerospace
division of Kawasaki Heavy Industries
. It produces aircraft
, space systems, simulators
, jet engine
s, missile
s, and electronic equipment.
during the 1930s and 1940s. In the post-war era, it produced numerous aircraft under license from American manufacturers for Japan Air Self-Defense Force
and Japan Maritime Self-Defense Force
s. The company became part of Kawasaki Heavy Industries
(KHI) in 1969.
Kawasaki Aircraft Industries was founded in 1918 as subsidiary of heavy-industrial conglomerate Kawasaki Heavy Industries
in Kobe. Prior to the end of World War II
Kawasaki mostly supplied aircraft and aircraft engines to the Imperial Japanese Army Air Force (IJAAF).
In the early 1930s, Kawasaki built Salmson
biplane
s and engines under license, and also developed a number of its own designs. Kawasaki hired the noted German Aerospace engineer
and designer, Dr. Richard Vogt
, from 1923-1933 to assist with design work and to train Japanese engineers. Among Vogt's pupils was Takeo Doi
the future chief designer for Kawasaki. Vogt later went on to become chief designer for Blohm & Voss.
Kawasaki obtained a license from Dornier
for all-metal construction flying boat
s, and the Kawasaki-Dornier Wal made a notable flight in December 1924; however, Kawasaki thereafter specialized in land planes. Noted designs include the:
after the end of World War II
, all of Japan's aerospace industry was dismantled, designs destroyed and plants converted to other uses. After the ban on aircraft development was lifted, in March 1954, a new company was founded by the merger of subsidiary companies K.K. Kawasaki Gifu Seisakusho and Kawasaki Kikai Kogyo K.K., retaining the name of the pre-war Kawasaki Kokuki Kogyo KK,
The Kawasaki KAL-1 (July 1953) was the first postwar all-metal aircraft of Japanese design. Early production covered 210 Lockheed T-33 jet trainers, 48 Lockheed P-2H Neptune maritime patrol aircraft and 239 Bell 47
helicopter
s, all under license from the United States. Kawasaki was also a major subcontractor for components for the domestically-developed NAMC YS-11
turboprop transport.
Kawasaki Kokuki K.K. was dissolved and became a division of the reorganized Kawasaki Heavy Industries
(KHI) in April 1969.
, the company concentrated primarily on licensed production of derivatives of American patrol aircraft and helicopters through the 1990s. Kawasaki built 82 P-2J
s (derived from the Lockheed P-2 Neptune), 211 KH-4 helicopters (derived from the Bell 47
), 160 Kawasaki KV-107 helicopters (derived from the Boeing Vertol 107 Model II), and Hughes/McDonnell Douglas Model 500D
and OH-6DA helicopters. Kawasaki also built 101 P-3C
antisubmarine warfare patrol airplanes plus four EP-3/UP-3D electronic intelligence/training variants, and 68 CH-47J / JA
.
In the 1990s, Kawasaki became prime contractor on the new OH-1 armed scout, observation and attack helicopter
(first flown August 1996), and completed some 200 T-4 intermediate jet trainers and liaison aircraft for the JASDF by 1998. It is currently developing two large, next-generation aircraft, the XP-1
maritime patrol airplane and the XC-2 transport aircraft.
Kawasaki also continues to build helicopters, including the BK117, jointly developed and manufactured with MBB
. Kawasaki began delivery of MCH-101 mine sweeping and transport helicopter in 2006 to Japan Maritime Self-Defense Force
.
In the commercial aviation business, KHI is involved in the joint international development and production of large passenger aircraft. It is involved in joint development and production of the Boeing 767
and Boeing 777
with The Boeing Company
, and the 170, 175, 190 and 195 jets
with Empresa Brasileira de Aeronáutica
. It is also involved in the joint international development and production of turbofan engines
for passenger aircraft such as the V2500
, the RB211/Trent
, the PW4000
and the CF34.
Kawasaki also works for the Japan Aerospace Exploration Agency
. KHI was responsible for the development and production of the payload fairings, payload attach fittings (PAF) and the construction of the launch complex for the H-II
rocket. It continues to provide services for the H-IIA
rocket.
Aerospace manufacturer
An aerospace manufacturer is a company or individual involved in the various aspects of designing, building, testing, selling, and maintaining aircraft, aircraft parts, missiles, rockets, and/or spacecraft....
division of Kawasaki Heavy Industries
Kawasaki Heavy Industries
is an international corporation based in Japan. It has headquarters in both Chūō-ku, Kobe and Minato, Tokyo.The company is named after its founder Shōzō Kawasaki and has no connection with the city of Kawasaki, Kanagawa....
. It produces aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
, space systems, simulators
Flight simulator
A flight simulator is a device that artificially re-creates aircraft flight and various aspects of the flight environment. This includes the equations that govern how aircraft fly, how they react to applications of their controls and other aircraft systems, and how they react to the external...
, jet engine
Jet engine
A jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
s, missile
Missile
Though a missile may be any thrown or launched object, it colloquially almost always refers to a self-propelled guided weapon system.-Etymology:The word missile comes from the Latin verb mittere, meaning "to send"...
s, and electronic equipment.
Pre-war genesis
was one of Japan's first aircraft companies. It developed numerous types of aircraft for the Imperial Japanese ArmyImperial Japanese Army
-Foundation:During the Meiji Restoration, the military forces loyal to the Emperor were samurai drawn primarily from the loyalist feudal domains of Satsuma and Chōshū...
during the 1930s and 1940s. In the post-war era, it produced numerous aircraft under license from American manufacturers for Japan Air Self-Defense Force
Japan Air Self-Defense Force
The , or JASDF, is the aviation branch of the Japan Self-Defense Forces responsible for the defense of Japanese airspace and other aerospace operations. The JASDF carries out combat air patrols around Japan, while also maintaining an extensive network of ground and air early warning radar systems...
and Japan Maritime Self-Defense Force
Japan Maritime Self-Defense Force
The , or JMSDF, is the naval branch of the Japan Self-Defense Forces, tasked with the naval defense of Japan. It was formed following the dissolution of the Imperial Japanese Navy after World War II....
s. The company became part of Kawasaki Heavy Industries
Kawasaki Heavy Industries
is an international corporation based in Japan. It has headquarters in both Chūō-ku, Kobe and Minato, Tokyo.The company is named after its founder Shōzō Kawasaki and has no connection with the city of Kawasaki, Kanagawa....
(KHI) in 1969.
Kawasaki Aircraft Industries was founded in 1918 as subsidiary of heavy-industrial conglomerate Kawasaki Heavy Industries
Kawasaki Heavy Industries
is an international corporation based in Japan. It has headquarters in both Chūō-ku, Kobe and Minato, Tokyo.The company is named after its founder Shōzō Kawasaki and has no connection with the city of Kawasaki, Kanagawa....
in Kobe. Prior to the end of World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
Kawasaki mostly supplied aircraft and aircraft engines to the Imperial Japanese Army Air Force (IJAAF).
In the early 1930s, Kawasaki built Salmson
Salmson 2
|-References:* Davilla, James J., & Soltan, Arthur M., French Aircraft of the First World War. Stratford, Connecticut: Flying Machines Press, 1997. ISBN 0-9637110-4-0...
biplane
Biplane
A biplane is a fixed-wing aircraft with two superimposed main wings. The Wright brothers' Wright Flyer used a biplane design, as did most aircraft in the early years of aviation. While a biplane wing structure has a structural advantage, it produces more drag than a similar monoplane wing...
s and engines under license, and also developed a number of its own designs. Kawasaki hired the noted German Aerospace engineer
Aerospace engineering
Aerospace engineering is the primary branch of engineering concerned with the design, construction and science of aircraft and spacecraft. It is divided into two major and overlapping branches: aeronautical engineering and astronautical engineering...
and designer, Dr. Richard Vogt
Richard Vogt (aircraft designer)
Richard Vogt was a German engineer and aircraft designer.He is well known as a designer of unique warplanes, including an asymmetrically-shaped reconnaissance aircraft and a nuclear-powered bomber, during and after World War II.- Biography :Richard Vogt was born in Schwäbisch Gmünd, a town in the...
, from 1923-1933 to assist with design work and to train Japanese engineers. Among Vogt's pupils was Takeo Doi
Takeo Doi (aircraft designer)
was a Japanese aircraft designer.He designed many World War II fighter aircraft used by the Imperial Japanese Army Air Force. His most important work was the , aka Kawasaki Ki-61 or "Tony"....
the future chief designer for Kawasaki. Vogt later went on to become chief designer for Blohm & Voss.
Kawasaki obtained a license from Dornier
Dornier Flugzeugwerke
Dornier Flugzeugwerke was a German aircraft manufacturer founded in Friedrichshafen in 1914 by Claudius Dornier. Over the course of its long lifespan, the company produced many notable designs for both the civil and military markets.-History:...
for all-metal construction flying boat
Flying boat
A flying boat is a fixed-winged seaplane with a hull, allowing it to land on water. It differs from a float plane as it uses a purpose-designed fuselage which can float, granting the aircraft buoyancy. Flying boats may be stabilized by under-wing floats or by wing-like projections from the fuselage...
s, and the Kawasaki-Dornier Wal made a notable flight in December 1924; however, Kawasaki thereafter specialized in land planes. Noted designs include the:
- Type 88 - reconnaissance biplane (1927)
- Type 92Kawasaki Type 92|-References:NotesBibliography...
- single-seat biplane fighter (1930) - Ki-3Kawasaki Ki-3|-See also:-References:NotesBibliography...
- single-engine biplane bomber (1933) - Ki-10Kawasaki Ki-10|-See also:-External links:* *...
- single-seat fighter biplane (1935) - Ki-32Kawasaki Ki-32|-See also:-External links:*...
- single-engine monoplane bomber (1937) - Ki-45Kawasaki Ki-45The Kawasaki Ki-45 Toryu was a two-seat, twin-engine fighter used by the Imperial Japanese Army in World War II. The army gave it the designation "Type 2 Two-Seat Fighter"; the Allied reporting name was "Nick"....
- twin-engine fighter (1939) - Ki-48Kawasaki Ki-48The Kawasaki Ki-48, 九九式双発軽爆撃機 'Sokei', Army Type 99 Twin-engined Light Bomber, was a Japanese twin-engine light bomber that was used during World War II. Its Allied reporting name was "Lily".-Development:...
- twin-engine light bomber (1939) - Ki-56Kawasaki Ki-56|-See also:-References:NotesBibliography* Francillon, Ph.D., René J. Japanese Aircraft of the Pacific War. London: Putnam & Company, 1970 . ISBN 0-370-30251-6....
- twin-engine light transport (1940) - Ki-60Kawasaki Ki-60-See also:-References:NotesBibliography* Bueschel, Richard M. Kawasaki Ki.61/Ki.100 Hien in Japanese Army Air Force Service, Aircam Aviation Series No.21. Canterbury, Kent, UK: Osprey Publications Ltd, 1971. ISBN 0-85045-026-8....
- single-engine experimental fighter (1941) - Ki-61Kawasaki Ki-61The Kawasaki Ki-61 Hien was a Japanese World War II fighter aircraft used by the Imperial Japanese Army Air Force...
- single-seat fighter (1941) - Ki-96Kawasaki Ki-96-See also:-References:NotesBibliography* Francillon, Ph.D., René J. Japanese Aircraft of the Pacific War. London: Putnam & Company Ltd., 1970 . ISBN 0-370-30251-6....
- twin-engine experimental fighter (1941) - Ki-100Kawasaki Ki-100The Kawasaki Ki-100 was a fighter aircraft used by the Imperial Japanese Army in World War II. The Japanese Army designation was "Type 5 Fighter"...
radial-engine fighter (1944) - Ki-102Kawasaki Ki-102-See also:-References:NotesBibliography* Francillon, Ph.D., René J. Japanese Aircraft of the Pacific War. London: Putnam and Company Ltd., 1979. ISBN 0-370-30251-6....
- twin-engine fighter (1944)
Post-war development
During the occupation of JapanOccupied Japan
At the end of World War II, Japan was occupied by the Allied Powers, led by the United States with contributions also from Australia, India, New Zealand and the United Kingdom. This foreign presence marked the first time in its history that the island nation had been occupied by a foreign power...
after the end of World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, all of Japan's aerospace industry was dismantled, designs destroyed and plants converted to other uses. After the ban on aircraft development was lifted, in March 1954, a new company was founded by the merger of subsidiary companies K.K. Kawasaki Gifu Seisakusho and Kawasaki Kikai Kogyo K.K., retaining the name of the pre-war Kawasaki Kokuki Kogyo KK,
The Kawasaki KAL-1 (July 1953) was the first postwar all-metal aircraft of Japanese design. Early production covered 210 Lockheed T-33 jet trainers, 48 Lockheed P-2H Neptune maritime patrol aircraft and 239 Bell 47
Bell 47
The Bell 47 is a two-bladed, single engine, light helicopter manufactured by Bell Helicopter. Based on the third Model 30 prototype, Bell's first helicopter designed by Arthur M. Young, the Bell 47 became the first helicopter certified for civilian use on 8 March 1946...
helicopter
Helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...
s, all under license from the United States. Kawasaki was also a major subcontractor for components for the domestically-developed NAMC YS-11
NAMC YS-11
The NAMC YS-11 is a turboprop airliner built by a Japanese consortium, the Nihon Aircraft Manufacturing Corporation. The program was initiated by the Ministry of International Trade and Industry in 1954, the aircraft was rolled out in 1962, and production ceased in 1974.-Development and design:In...
turboprop transport.
Kawasaki Kokuki K.K. was dissolved and became a division of the reorganized Kawasaki Heavy Industries
Kawasaki Heavy Industries
is an international corporation based in Japan. It has headquarters in both Chūō-ku, Kobe and Minato, Tokyo.The company is named after its founder Shōzō Kawasaki and has no connection with the city of Kawasaki, Kanagawa....
(KHI) in April 1969.
Under Kawasaki Heavy Industries
In April 1969, the former Kawasaki Kokuki K.K. was dissolved and became a division of the reorganized Kawasaki Heavy Industries (KHI). Kawasaki is a major contractor for the Japanese Ministry of Defense. Although in November 1970, Kawasaki completed Japan's first domestically designed twin turbofan military transport, the C-1Kawasaki C-1
|-See also:-References:* Taylor, John W.R. . Jane's All The World's Aircraft 1976-77. London:Jane's Yearbooks, 1976, ISBN 0-354-00538-3....
, the company concentrated primarily on licensed production of derivatives of American patrol aircraft and helicopters through the 1990s. Kawasaki built 82 P-2J
Kawasaki P-2J
|-See also:-References:* Sullivan, Jim, P2V Neptune in action. Squadron/Signal Publications: Carrollton, TX, 1985.-External links:* * http://p2vneptune.com* http://www.maam.org/neptune/p2_1.html...
s (derived from the Lockheed P-2 Neptune), 211 KH-4 helicopters (derived from the Bell 47
Bell 47
The Bell 47 is a two-bladed, single engine, light helicopter manufactured by Bell Helicopter. Based on the third Model 30 prototype, Bell's first helicopter designed by Arthur M. Young, the Bell 47 became the first helicopter certified for civilian use on 8 March 1946...
), 160 Kawasaki KV-107 helicopters (derived from the Boeing Vertol 107 Model II), and Hughes/McDonnell Douglas Model 500D
MD Helicopters MD 500
The MD Helicopters MD 500 series is an American family of light utility civilian and military helicopters. The MD 500 was developed from the Hughes 500, a civilian version of the US Army's OH-6A Cayuse/Loach...
and OH-6DA helicopters. Kawasaki also built 101 P-3C
P-3 Orion
The Lockheed P-3 Orion is a four-engine turboprop anti-submarine and maritime surveillance aircraft developed for the United States Navy and introduced in the 1960s. Lockheed based it on the L-188 Electra commercial airliner. The aircraft is easily recognizable by its distinctive tail stinger or...
antisubmarine warfare patrol airplanes plus four EP-3/UP-3D electronic intelligence/training variants, and 68 CH-47J / JA
CH-47 Chinook
The Boeing CH-47 Chinook is an American twin-engine, tandem rotor heavy-lift helicopter. Its top speed of 170 knots is faster than contemporary utility and attack helicopters of the 1960s...
.
In the 1990s, Kawasaki became prime contractor on the new OH-1 armed scout, observation and attack helicopter
Attack helicopter
An attack helicopter is a military helicopter with the primary role of an attack aircraft, with the capability of engaging targets on the ground, such as enemy infantry and armored vehicles...
(first flown August 1996), and completed some 200 T-4 intermediate jet trainers and liaison aircraft for the JASDF by 1998. It is currently developing two large, next-generation aircraft, the XP-1
Kawasaki P-1
|-See also:-External links:* * * * * * , Kawasaki Heavy Industries Scope Quarterly Newsletter No.73 October 2007* * * *...
maritime patrol airplane and the XC-2 transport aircraft.
Kawasaki also continues to build helicopters, including the BK117, jointly developed and manufactured with MBB
Messerschmitt-Bölkow-Blohm
Messerschmitt-Bölkow-Blohm was a German aerospace company formed as the result of several mergers in the late 1960s. Among its best-known products was the MBB Bo 105 light twin helicopter...
. Kawasaki began delivery of MCH-101 mine sweeping and transport helicopter in 2006 to Japan Maritime Self-Defense Force
Japan Maritime Self-Defense Force
The , or JMSDF, is the naval branch of the Japan Self-Defense Forces, tasked with the naval defense of Japan. It was formed following the dissolution of the Imperial Japanese Navy after World War II....
.
In the commercial aviation business, KHI is involved in the joint international development and production of large passenger aircraft. It is involved in joint development and production of the Boeing 767
Boeing 767
The Boeing 767 is a mid-size, wide-body twin-engine jet airliner built by Boeing Commercial Airplanes. It was the manufacturer's first wide-body twinjet and its first airliner with a two-crew glass cockpit. The aircraft features two turbofan engines, a supercritical wing, and a conventional tail...
and Boeing 777
Boeing 777
The Boeing 777 is a long-range, wide-body twin-engine jet airliner manufactured by Boeing Commercial Airplanes. It is the world's largest twinjet and is commonly referred to as the "Triple Seven". The aircraft has seating for over 300 passengers and has a range from , depending on model...
with The Boeing Company
Boeing
The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois since 2001...
, and the 170, 175, 190 and 195 jets
Embraer E-Jets
The Embraer E-Jets are a series of narrow-body, twin-engine, medium-range, jet airliners produced by Embraer, a Brazilian aerospace conglomerate that produces commercial, military, and corporate aircraft. Announced at the Paris Air Show in 1999, and entering production in 2002, the aircraft series...
with Empresa Brasileira de Aeronáutica
Embraer
Embraer S.A. is a Brazilian aerospace conglomerate that produces commercial, military, and executive aircraft and provides aeronautical services....
. It is also involved in the joint international development and production of turbofan engines
Turbofan
The turbofan is a type of airbreathing jet engine that is widely used for aircraft propulsion. A turbofan combines two types of engines, the turbo portion which is a conventional gas turbine engine, and the fan, a propeller-like ducted fan...
for passenger aircraft such as the V2500
International Aero Engines V2500
The IAE V2500 is a two-shaft high-bypass turbofan engine which powers the Airbus A320 family , and the McDonnell Douglas MD-90. International Aero Engines is a consortium backed by four aero-engine manufacturers, formed in 1983 to produce the engine...
, the RB211/Trent
Rolls-Royce RB211
The Rolls-Royce RB211 is a family of high-bypass turbofan engines made by Rolls-Royce plc and capable of generating 37,400 to 60,600 pounds-force thrust. Originally developed for the Lockheed L-1011 , it entered service in 1972 and was the only engine to power this aircraft type...
, the PW4000
Pratt & Whitney PW4000
|-See also:-External links:* * *...
and the CF34.
Kawasaki also works for the Japan Aerospace Exploration Agency
Japan Aerospace Exploration Agency
The , or JAXA, is Japan's national aerospace agency. Through the merger of three previously independent organizations, JAXA was formed on October 1, 2003, as an Independent Administrative Institution administered by the Ministry of Education, Culture, Sports, Science and Technology and the...
. KHI was responsible for the development and production of the payload fairings, payload attach fittings (PAF) and the construction of the launch complex for the H-II
H-II
The H-II rocket was a Japanese satellite launch system, which flew seven times between 1994 and 1999, with five successes. It was developed by NASDA in order to give Japan a capability to launch larger satellites in the 1990s. It was the first two-stage liquid-fuelled rocket Japan made using only...
rocket. It continues to provide services for the H-IIA
H-IIA
H-IIA is an active expendable launch system operated by Mitsubishi Heavy Industries for the Japan Aerospace Exploration Agency . The liquid-fueled H-IIA rockets have been used to launch satellites into geostationary orbit, to launch a lunar orbiting spacecraft, and to launch an interplanetary...
rocket.
Main products
- Aircraft
- Kawasaki C-1Kawasaki C-1|-See also:-References:* Taylor, John W.R. . Jane's All The World's Aircraft 1976-77. London:Jane's Yearbooks, 1976, ISBN 0-354-00538-3....
- twin-turbofan military transport - Kawasaki C-2 - advanced military transport
- Kawasaki OH-1 - light helicopter
- Kawasaki P-1Kawasaki P-1|-See also:-External links:* * * * * * , Kawasaki Heavy Industries Scope Quarterly Newsletter No.73 October 2007* * * *...
- advanced maritime patrol aircraft - Kawasaki T-4 - intermediate jet trainer
- Kawasaki C-1
- Space systems
- SimulatorsFlight simulatorA flight simulator is a device that artificially re-creates aircraft flight and various aspects of the flight environment. This includes the equations that govern how aircraft fly, how they react to applications of their controls and other aircraft systems, and how they react to the external...
- Jet engineJet engineA jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
s - MissileMissileThough a missile may be any thrown or launched object, it colloquially almost always refers to a self-propelled guided weapon system.-Etymology:The word missile comes from the Latin verb mittere, meaning "to send"...
s- Type 64 MATType 64 MATThe was a Japanese wire guided anti-tank missile developed during the late 1950s. The missile is a broadly similar to the Swiss/German Cobra and the 9M14 Malyutka...
- anti-tank missile - Type 79 Jyu-MATType 79 Jyu-MATThe is a Japanese SACLOS guided anti-tank missile that entered service with the JGSDF in 1984. It was initially issued to coastal defence units, intended to destroy troop and vehicle landing ships as they approached the shoreline. It is also known as KAM-9....
- anti-tank/landing-craft missile - Type 87 Chu-MATType 87 Chu-MATThe Chū-MAT is a Japanese laser guided anti-tank missile in service with the Japanese Ground Self-Defense Forces. It had been created as a front-line replace for the Type 64 MAT, pressed into service with the Type 79 Jyu-MAT.-History:...
- anti-tank missile - Type 96 Multi-Purpose Missile SystemType 96 Multi-Purpose Missile SystemThe is an Anti-tank/Landing craft missile used by the Japan Ground Self-Defense Force. It is the first Japanese missile system that uses a complete digitally controlled interface.- History :...
- anti-tank/landing-craft missile - Type 01 LMATType 01 LMATThe is a Japanese man-portable fire-and-forget anti-tank missile. Development began in 1993 at Kawasaki Heavy Industries and was accepted into service in 2001. During development, the missile was designated with the codename XATM-5...
- anti-tank missile
- Type 64 MAT
- Electronic equipment