BTR-80
BTR-80 | |
---|---|
Type | Armored personnel carrier |
Place of origin | Soviet Union Russia |
Service history | |
In service | 1986 – present |
Used by | See Operators |
Wars | Soviet War in Afghanistan Nagorno-Karabakh War Georgian Civil War Turkish-Kurdish conflict Transnistria War Tajikistan Civil War First Chechen War War of Dagestan Second Chechen War 2008 South Ossetian War Iraqi insurgency (2011–present) War in Donbass |
Production history | |
Manufacturer | Arzamas Machinery Plant, Nizhniy Novgorod[1] |
Produced | 1984 – present |
No. built | 5000+ |
Specifications | |
Mass | 13.6 tonnes (15.0 tons) |
Length | 7.7 m (25.3 ft) |
Width | 2.9 m (9.5 ft) |
Height | 2.41 m (7.9 ft) |
Crew | 3 (+7 passengers) |
Main armament | 14.5 mm KPVT machine gun or 30mm 2A72 automatic cannon |
Secondary armament | 7.62 mm PKT machine gun |
Engine | diesel KamAZ-7403 260 hp (190 kW) |
Power/weight | 19 hp/tonne |
Suspension | wheeled 8×8 |
Operational range | 600 km (372.8 mi) |
Maximum speed | 80-90 km/h (49.7–55.9 m/h) swim 10 km/h (6.2 m/h) |
The BTR-80 (Russian: бронетранспортер/Bronetransporter, literally "Armoured Transporter") is an 8x8 wheeled amphibious armoured personnel carrier (APC) designed in the USSR. It was adopted in 1986 and replaced the previous vehicles, the BTR-60 and BTR-70, in the Soviet Army.[2] It was first deployed during the Soviet war in Afghanistan.
Description
The Soviets based the BTR-80 on the BTR-70 APC. It has a single 260-hp, V-8 turbocharged, water-cooled, diesel engine, an improvement over the twin gasoline engines installed in the BTR-60 and BTR-70 vehicles. The reconfigured rear portion of the hull accommodates the new, single engine. The Soviets removed the roof chamfers of the modified BTR-70, raised the rear, and squared off the rearward-sloping engine compartment. Standard equipment includes TNPO vision blocks, TNP-B and TKN-3 optical devices for the driver and commander, an OU-3GA2M infra-red search light, six 81 mm smoke grenade launchers 902V "Tucha", a radioset (R-173 or R-163-50U), an intercom, and hydrojets for amphibious propulsion.
Capabilities
The Soviets modified the truncated cone turret used on the BTR-70 for the BTR-80 by redesigning the mantlet. This allows the 14.5 mm (1 in) KPVT and coaxial 7.62 mm (0 in) PKT machine guns to be elevated to a maximum of 60 degrees. This high angle of fire is useful in engaging targets on steep slopes, in urban fighting, and for engaging low slow flying air targets.[3] The Soviets have also modified the design and positioning of the firing ports; the ports are now round, rather than tear-shaped, and have ball mounts similar to those used on the BMP-1. The forward firing ports now sit in angled recesses, which allows infantry to fire from the front of the vehicle.
The redesigned side doors are split horizontally. The upper portion opens forward; this gives dismounting troops some protection against small arms fire from the front of the vehicle. The lower portion opens down, forming a step. Six smoke grenade projectors are mounted on the rear of the turret.
The BTR-80 can climb a slope with up to 60% gradient and climb a vertical step of 0.5 m.[4]
Remarks
In 1984, the Soviets began production of a diesel-engined variant of the BTR-70, which they called the BTR-80. The Soviets have retrofitted some BTR-70s with several of the improvements incorporated into the BTR-80, including the high-angle-of-fire turret. The twin doors are designed to allow the infantry to disembark while the vehicle is in motion, and allow the infantry inside to exit from one side if the other is receiving fire. The 30mm Cannon variants are effective against most targets apart from main battle tanks, against which they can still cause significant damage to optics, weapons, and important systems. The main gun is not stabilized, so accurate fire on the move is limited to low speeds, and the turret's rotation mechanism is manually operated. The gunner sits in a roof-mounted chair located above the flat floor behind the driver/commander and two passengers, and before the passenger bench. The gunner's station is basic, but uncharacteristically spacious for a Soviet armored vehicle. The gunner is equipped with both a day time optical sight and an infrared night sight.
Versions
Russian Federation
- BTR-80 (GAZ-5903) - armoured personnel carrier.
- BTR-80M - improved model with DMZ-238M2 engine of 240 hp, a slightly longer hull and new tires. In production since 1993. It is understood that only a small number were produced until the original engine was ready for production again.
- BTR-82 - latest production version with improved armour, spall liners, more modern night vision device TKN-4GA, GLONASS navigation system and a more powerful engine of 300 hp. The original armament is retained but is now installed in the BPPU turret of the BTR-80A/BTR-82A. The prototype of the BTR-82 was shown for the first time in November 2009.
- BTR-80K (GAZ-59031) (kommandnyj) - command vehicle APC with telescopic antenna mast, TNA-4 navigation device and R-163-50У series of radio equipment.
- BTR-80A (GAZ-59034) - IFV See pictures with 30 mm gun 2A72 and 300 rounds as primary weapon. The turret is called BPPU and is equipped with sights 1PZ-9 (day) and TPN-3 or TPN-3-42 "Kristall" (night). In production and service since 1994.[5]
- BTR-80S - variant of the BTR-80A for the Internal Troops of the MVD, equipped with a 14.5-mm machine gun KPVT and 7.62 mm PKT in the turret.
- BTR-80AK - command variant of the BTR-80A, with two whip antennas in the rear corners and with only 1 firing port on the right hull side.
- BRDM-3 (bronirovannaya razvedivatel’no-dozornaya mashina) - armoured reconnaissance/surveillance vehicle, based on the BTR-80AK and with a new day/night vision device in front of the commander's position. The crew consists of 6 men. Note that in some Western sources, the name BRDM-3 is incorrectly used for the 9P148 ATGM carrier.
- BTR-82A - latest production version with improved armour, spall liners, more modern night vision device TKN-4GA-02, 30 mm (1 in) gun 2A72, GLONASS navigation system and a more powerful engine of 300 hp. The prototype of the BTR-82A was shown for the first time in November 2009. The Ministry of Defense of Russia has formally adopted the armored personnel carrier BTR-82A. The corresponding order was signed by Defense Minister Sergey Shoygu in early 2013.[6] In a Syrian government TV channel report, BTR-82A is seen in battle in Syria around September 2015. The video shows BTR-82A crew members speaking Russian. It is widely suspected[by whom?] that Russian armoured vehicle units have been directly fighting anti-government groups in Syria.[7]
- BTR-82AM - refurbished BTR-80 to the level of BTR-82A.[8][9] Distinguished by a closed (welded) embrasure in the frontal part of the vehicle.[9] The first batch was delivered in 2013. Used by naval infantry.[10]
- BTR-87 - Modification of the BTR-82A that relocates the engine compartment to the front-right part of the hull, allowing troops to disembark through rear and roof hatches.[11]
- 2S23 "Nona-SVK" - fire support vehicle with the 120 mm 2A60 rifled gun/mortar - developed on the base of 2А51 rifled gun/mortar of the 2S9 Nona - and a crew of 4. Adopted in 1990.[12]
- BREM-K (GAZ-59033) (bronirovannaya remontno-evakuatsionnaya mashina) - armoured recovery vehicle with towbars, a winch, welding equipment and a light crane.
- KM-80 or BTR-80 PBKM - command vehicle.
- RKhM-4 (razvedivatel’naya khimicheskaya mashina) - NBC reconnaissance vehicle with detection devices including the IMD-21BA and DP-5V, an automatic chemical alarm system GSA-12, a detection set for chemical agents KPKhR-3, an MK-3M meteo set, a KPO-1 sampling device, an ASP automatic detector and a KZO-2 flag dispenser to mark contaminated areas.
- RKhM-4-01 - improved version with more modern equipment, including the GSA-13, IMD-1R, ASP-12 systems, a PGO-11 semi-automatic detection device, R-171M and R-173M radios instead of the older R-123M.
- RKhM-4-02 - with upgraded detection systems such as the ASP-13, IMD-2NM and IMD-23, GSA-14; analysis, storage and interface unit UIK-RKhB and T-235-1U COMSEC equipment.[13]
- RKhM-6 "Povozka" - latest version with state-of-the-art detection systems, including the PRKhDD-2B with a detection range of about 3 km. Furthermore, the RKhM-6 is equipped with an SN-RKhM inertial navigation system and a 14Ts834 satellite navigation system.[13] In service since 2013.[14]
- RPM-2 - mobile radiological reconnaissance station with KRPI system. In service since 2000. Might also be known as NKR (nazemnij kompleks radiatsionnoj razvedki, "ground nuclear recon complex").
- R-149BMRA - command and signals vehicle.
- R-149MA3 - command and signals vehicle.
- R-439-BK1 - SatCom station.
- "Tajfun-M" - new version for Strategic Rocket units (RVSN) that will replace the base security vehicles MBP on BTR-60/70 chassis. The BTR-80 version is equipped with a new turret with 7.62 mm machine gun, an unmanned aerial vehicle, new observation device TKN-4S and a "Kredo-1" radar. In service since 2013.[15]
- ZS-88 (zvukoveshchatel’naya stantsiya) - PsyOps vehicle with loudspeaker set.
- ZS-96 (zvukoveshchatel’naya stantsiya) - PsyOps vehicle with loudspeaker set.
- K1Sh1 (GAZ-59032) - command post vehicle with bigger hull and unarmed turret. Also known as UNSh (unifitsirovannyj shassi, "unified chassis"). This version serves as the basis for several specialised vehicles, but Estonia uses the type as APC with machine gun turret.
- BMM-80 "Simfoniya" (GAZ-59039) (bronirovannaya mnogofunktsionalnaya meditsinskaya mashina) - armoured ambulance, comes in three versions each of which can transport 9 patients, including two on stretchers on the rear hull (Developed in 1993):
- BMM-1 (first aid and evacuation from the battle field),
- BMM-2 (initial medical treatment at battalion-level) and
- BMM-3 (mobile field hospital).
- E-351BrM - mobile electric power station. The vehicle is equipped with an AD-30T/400 diesel-electric generator that can deliver power to up to 15 signals vehicles. It has a 2-men crew.
- PU-12M6 (9S482M6) (punkt upravleniya) - battery command vehicle (BKP - batarejnyj kommandnyj punkt) for air defence units equipped with "Strela-1M" (SA-9), "Strela-10M2 (SA-13), "Osa-AK" (SA-8), 2S6 "Tunguska" and ZSU-23-4 "Shilka".
- PU-12M7 (9S482M7) - improved version.
- 1V152 - command and forward observer vehicle for field artillery units. The standard equipment consists of range finders, dag/night vision devices, navigation equipment etc. The 1V152 and 1V153 (on Ural-4320 truck) belong to the KSAUO "Kapustnik-B" set.[16][17]
- R-149BMR - signals vehicle, equipped with R-168-100KA “Akveduk-100KA”, R-168-100U, R-163-25U, R-163-10V, and R-163-1V “Arbalet” HF/VHF radio sets, AVSK intercom, P-338 video system, AD-3,5U-28,5 generator, ASh-4 telescopic mast, AZI NVIS HF antenna and ShDA-50 Discone-type antenna.
- R-149MA3 - command and signals vehicle.
- R-165B - HF signals vehicle equipped with “Arbalet-500K”, R-163-10V and -50, R-163-AR radios, R-016V "Vishnya" HF link equipment and an AB-4U-P28.5-1V generator. The radio sets have a declared range of 20–350 km on the move and 40–1000 km deployed.
- R-439-MD2 - SatCom station.
- R-439-BK "Legenda 2BK" - SatCom station, operates within 3400-3900 MHz (receiption) and 5725-6225 MHz (transmission) ranges.
- P-240BTZ - switchboard vehicle with "Zenit" set. Planned successor for the BTR-60 based P-240BT.
- BMM-80 "Simfoniya" (GAZ-59039) (bronirovannaya mnogofunktsionalnaya meditsinskaya mashina) - armoured ambulance, comes in three versions each of which can transport 9 patients, including two on stretchers on the rear hull (Developed in 1993):
- "Infauna" - An electronic countermeasures variant created for the Airborne Troops; it is "designed to interfere with radio-controlled explosive devices ... as well as jamming the enemy’s tactical communications systems".[18] The VDV accepted the first four vehicles into active service in early July 2012 after completing field evaluation which started in early 2012.[19]
- BTR-90
Colombia
- BTR-80 "Caribe" - version for Colombian marines with .50cal machine gun instead of 14.5 mm KPVT. 100 ordered. Caribe project is assembled in COTECMAR (Corporación Tecnológica del Mar Caribe) Plant in Cartagena de Indias, Colombia[20]
Estonia
- BTR-80UNSh (EST) - Estonian version of the BTR-80. After Estonia re-gained independence in 1991, about 20 BTR-80s were taken over from Russian contrabandists[citation needed] and used until 2005 as infantry squad carriers. Replaced by Sisu XA-180EST APCs.
Hungary
- BTR-80M - Upgraded version with passive day/night sight KM-1M on top of the roof, stowage box for water bottles on the left hull side, improved NBC protection system and Kronsberg radio set.[21]
- BTR-80 GKKO - Turret-less version with observation equipment. Prototype.
- BTR-80 MPAEJ (műszaki páncélozott akadály elháritó jármű) - Unarmed combat engineer version without turret. In service.[22]
- BTR-80 MPFJ (műszaki páncélozott felderitő jármű) - Unarmed obstacle clearing vehicle without turret. In service.[23]
- BTR-80 MVJ (mentő-vontató jármű) - Repair and recovery vehicle with crane and winch. In service.[24]
- BTR-80 SKJ (sebesült kihordó jármű) - Much modified ambulance version with bigger troop compartment.[25]
- BTR-80 VSF (vegyi-sugár felderítő jármű) - NBC reconnaissance vehicle. In service.[26]
North Korea
- 8x8 - Following the acquisition of 32 BTR-80As, North Korea appears to have produced and put into service a domestic clone of the vehicle of an unknown designation. It carries 3 crew and 7-8 troops and is fitted with an indigenous turret equipped with two 14.5 mm and one 7.62 mm machine guns. Other features such as protection, engine placement, entry and exit points, and amphibious capabilities are similar to the BTR-80.[27]
- 6x6 - North Korea also developed a 6x6 version of the BTR-80A to carry troops and cargo under armor and for reconnaissance. It carries 3 crew and 6 troops and is fitted with the same indigenous turret. There is a door on either side of the hull, and it otherwise has the same protection, engine placement, and amphibious capabilities.[28]
Romania
- TAB Zimbru (B33) (transportorul amfibiu blindat) - modified version of the BTR-80 with Model 1240 V8-DTS engine of 268 hp (197 kW), R-1231B radio set and 500 additional rounds 7.62 mm. Made by CN RomArm SA.
Ukraine
- BTR-80UP - improved version, produced in Ukraine in cooperation with Poland for Iraq (98 planned). Fitted with a new 300 hp engine, additional armour and airconditioner.[29]
- BTR-80UP-KB - battalion level command vehicle.
- BTR-80UP-KR - company level command vehicle.
- BTR-80UP-S - staff vehicle.
- BTR-80UP-M - ambulance.
- BTR-80UP-BREM - recovery vehicle.
- BTR-80UP-R - reconnaissance version.
- BTR-80UP-T - cargo version.
- BTR-94
- BTR-3U "Okhotnik" - not an upgrade of the BTR-80, but is a new vehicle similar to the Soviet design.[30]
- BTR-4 - an extensive redesign of the BTR-80/BTR-3 where troops enter and leave the vehicle either through the rear doors or the roof hatches, and the driver and the commander are provided with doors located on the sides of the hull.
- KShM "Kushetka-B" - command vehicle, based on the K1Sh1 chassis and developed by Radiopribor from Ukraine. The specialised equipment consists of the “Berkut-M” HF radioset and several, VHF sets - R-171M, R-173M “Abzats-M”, R-163-50U, R-163-10V and R-163-1V “Arbalet” (with a range from 5 to 350 km). Other equipment includes a navigation apparatus (probably TNA-4-6), an AB-1-P28,5-B-V1 generator as well as DLYa4.115.002 and DLYa2.091.008 telescopic antenna masts.[31]
Operators
Current operators
- Afghanistan
- Algeria
- Angola
- Armenia - 160 in service of the Armenian Army.[32][33]
- Azerbaijan - 70 BTR-80A ordered in 2007, delivered 2007-2010.[34]
- Bangladesh - second largest user of BTR-80. 1030 in service (14 ordered in 1994, 78 ordered in 2001 and 60 ordered in 2005; 118 of them intended for peacekeeping operations and financed through the UN). From 2008 to 2009, Bangladesh procured 140 BTR-80 which includes 120 APC, 10 ARV and 10 APC ambulance version.[35] An additional 80 are on order since 2011.[36] On 2012 Bangladesh procured 150 BTR-80 which includes 140 APC, 5 ARV and 5 APC ambulance version.More 330 BTR-82A on order . [37]
Some of the buying can't be traced due to secrecy during buying.
- Belarus - 194.[38] Ordered BTR-82A.[39]
- Colombia - 5 in service. Initially 100 units would be assembled under license in Colombia.
- Djibouti - 15 in service
- Estonia - 20 in service, as of 2013.
- Georgia
- Hungary - 513 BTR-80s and 178 BTR-80As obtained in exchange for Russian government debt.[citation needed]
- India
- Indonesia - Indonesian Navy Marine Corps (Korps Marinir TNI-AL) operates BTR-80A. From 2006, 12 BTR-80As are part of the Indonesian UNIFIL Mission in Lebanon.[40]
- Iraq - BTR-94 (50), BTR-80UP (98), BTR-4 (~88).[41]
- Ivory Coast 6 BTR-80 from Belarus
- Kazakhstan - 190 BTR-80, 90 BTR-80A
- Kenya - 8 BRDM-3, arrived in early 2012 from Russia.
- Kyrgyzstan - 8
- Macedonia - 12
- Moldova - 11 (5 for army, 5 for police special forces and 1 for carabinier troops)
- Mongolia - 20 BTR-80M are in service as of 2011.[42]
- North Korea - 32 BTR-80A (according to SIPRI trade registers)
- Pakistan - 120 BTR-70 / BTR-80 in service of the Pakistan Army.[43]
- Romania - 70 TAB Zimbru
- Russia - 1,152 BTR-80/80A/82A.[44] Beginning from 2010, BTR-82/82A purchased.[45] About 300 BTR-82A and BTR-82AM are in service.[46][47][48][49]
- Sri Lanka - 33 BTR-80/80A[50]
- Sudan - 30 BTR-80A (known as Shareef)
- Syria - Delivered 2013-2014 as part of the deal for abandoning chemical weapons.[51]
- Tajikistan - 26[52]
- Turkey - 214
- Turkmenistan - 40
- Ukraine - 456[53]
- Uzbekistan - 290
- Venezuela - 114 BTR-80A ordered in 2009.[54] All delivered by July 2012.[55]
- Donetsk People's Republic - 300
Museum exhibits
References
- ^ "Продукция - АМЗ". Retrieved 26 November 2014.
- ^ "История предприятия". Retrieved 18 October 2015.
- ^ Zaloga 1990: "The turret on the BTR-80 uses a new trunnion mounting which gives greater elevation for firing at enemy helicopters."
- ^ ARG. "BTR-80 Armored Personnel Carrier". Military-Today.com. Retrieved 15 July 2013.
- ^ http://www.army-technology.com/projects/btr80/
- ^ "BTR-82A adopted". Retrieved 26 November 2014.
- ^ "BTR-82A joins Syrian civil war". Retrieved 8 September 2015.
- ^ "BTR-82A BTR-82AM Armoured infantry fighting vehicle". Armyrecognition.com. Retrieved 7 February 2015.
- ^ a b Берзов, Сергей (7 September 2014). Российский телеканал по ошибке опубликовал видео уничтоженного бронетранспортера БТР-82АМ [Russian TV-channel unintentionally published video of a destroyed BTR-82AM]. Military-Informant.com (in Russian). Retrieved 7 February 2015.
- ^ "BTR-82AM Amphibious Armoured Personnel Carrier (APC), Russia". army-technology.com. Kable. Retrieved 7 February 2015.
- ^ Russia to upgrade its BTR-82A armoured personnel carrier to BTR-87 - Armyrecognition.com, 24 March 2016
- ^ http://mz.perm.ru/eng/business/products-catalog/pg1/rz154/231/
- ^ a b "«ЗАВОД ТУЛА" (PDF) (Press release). ОТКРЫТОЕ АКЦИОНЕРНОЕ ОБЩЕСТВО. Retrieved 15 July 2013.
- ^ "ЮВО России: войска РХБ защиты перевооружаются на современные мобильные комплексы". Retrieved 26 November 2014.
- ^ "ТАСС: Сибирь - В Новосибирской области соединения РВСН успешно отразили действия условного противника". ТАСС. Retrieved 26 November 2014.
- ^ "Капустник-Б", автоматизированная система управления огнем ствольной артиллерии, минометов и реактивных систем залпового огня — ОРУЖИЕ РОССИИ, Федеральный электронный справочник вооружения и военной техники
- ^ лБРХУФОЙЛ-в :: чойй "уЙЗОБМ" Archived 1970-01-01 at the Wayback Machine
- ^ Russian Airborne Gets New ECM System
- ^ http://www.deagel.com/Special-Purpose-Vehicles/Infauna_a000348009.aspx
- ^ Colombia: Seguridad y Defensa Archived 1970-01-01 at the Wayback Machine
- ^ eredmeny
- ^ névtelen
- ^ névtelen
- ^ névtelen
- ^ névtelen
- ^ névtelen
- ^ North Korean 8x8 APC - Military-Today.com
- ^ North Korean 6x6 APC - Military-Today.com
- ^ Altair - R-wto 12/2006 - BTR-80UP do Iraku. Sokoły chyba nie
- ^ "BTR-3U is not an upgrade of BTR-80". Retrieved 26 November 2014.
- ^ Военная кафедра МТУСИ :: Командно-штабная машина "Кушетка-Б" на транспортной базе БТР-80
- ^ IISS (2007). The Military Balance 2007. London: Routledge for the IISS. p. 155. ISBN 978-1-85743-437-8.
- ^ Template:Ru icon [1].
- ^ Sipri Arms Trade Register. Retrieved 14 August 2013.
- ^ http://www.prothom-alo.com/national/article/41672/ BTR-80
- ^ SIPRI Armstrade Register. Retrieved 9 June 2013.
- ^ http://www.prothom-alo.com/national/article/41672/
- ^ Belarus Army Equipment
- ^ http://tass.ru/armiya-i-opk/2247673
- ^ "BTR-80, Kendaraan Tempur Angkut Pasukan". Retrieved 26 November 2014.
- ^ "- General Topics". www.arabic-military.com. Retrieved 26 November 2014.
- ^ Trade Registers. Armstrade.sipri.org. Retrieved on 2013-06-09.
- ^ "Pakistan Army".
- ^ Eugene Yanko, Copyright 1997 - info@warfare.ru. "BTR-80/82A; Russian Arms, Military Technology, Analysis of Russia's Military Forces". Warfare.ru. Retrieved 26 November 2012.
{{cite web}}
: CS1 maint: numeric names: authors list (link) - ^ Военные отвергли БТР-90, упрекнув поставщиков в увлечении "косметикой" | РИА Новости (in Russian). Ria.ru. 28 October 2011. Retrieved 15 July 2013.
- ^ "Lenta.ru: Наука и техника: Военные в Чечне получили новые бронетранспортеры БТР-82А". Retrieved 26 November 2014.
- ^ "Russia Fields New Hard-Hitting Weapons Systems in 2013". Retrieved 26 November 2014.
- ^ "- .name". Retrieved 26 November 2014.
- ^ "Самарские военные получили около 300 бронетранспортеров - Еженедельник "Военно-промышленный курьер"". Retrieved 26 November 2014.
- ^ "Asia Times, Deadly arsenals dot Sri Lanka". Retrieved 26 November 2014.
- ^ http://imp-navigator.livejournal.com/260790.html БТР-80 в Сирии
- ^ Tajik-Army Equipment
- ^ Ground Forces Equipment - Ukraine
- ^ Sipri Armstrade Register. Retrieved 13 August 2013.
- ^ Completed vehicle deliveries - Ruaviation.com, 20 July 2012
- ^ "Panssarimuseon kesä 2011" (PDF) (Press release). panssarimuseo. 2011. Retrieved 15 July 2013.
- Zaloga, Steven J. (1990). Soviet Wheeled Armored Vehicles. Hong Kong: Concord Publications. ISBN 962-361-013-0.
- Hull/Markov/Zaloga (1999). Soviet/Russian Armor and Artillery Design Practices: 1945 to Present. Darlington Productions. ISBN 1-892848-01-5
- UN register of conventional arms