ZSU - 57 - 2 The ZSU - 57 - 2 ( Ob ' yekt 500 ) is a Soviet self - propelled anti - aircraft gun ( SPAAG ) , armed with two 57 mm autocannon s . ' ZSU ' stands for " Zenitnaya Samokhodnaya Ustanovka " ( ) , meaning " anti - aircraft self - propelled mount " , ' 57 ' stands for the bore of the armament in millimetres and ' 2 ' stands for the number of gun barrels . It was the first Soviet mass - produced tracked SPAAG . In the USSR it had the unofficial nickname " Sparka " , meaning " pair " , referring to the twin autocannon with which the vehicle is armed . Development history . Origins . During World War II , ground - attack aircraft emerged as a significant threat to mechanized units on the move . Conventional towed anti - aircraft ( AA ) artillery was an inadequate response under such conditions owing to the time needed to bring anti - aircraft machine guns into action . This experience made it clear that an anti - aircraft tracked vehicle , armed with small - bore autocannons or heavy machine guns , was needed . Vehicles such as the German Wirbelwind and specialized variants of the lend - leased M5 halftrack had been used to good effect in the final battles of World War II . In 1942 , Soviet engineers developed the T - 60 - 3 . The vehicle , based on the T - 60 light tank chassis , was armed with two 12 . 7 mm DShK heavy machine guns ; but the prototype did not go into production because of flaws in the design . The SU - 72 SPAAG and several other experimental vehicles based on the T - 60 or T - 70 light tank chassis and armed with 37 mm autocannon were also tested in 1942 – 1943 . The ZSU - 37 was based on the chassis of the SU - 76 M self - propelled gun ( SPG ) and armed with a 37 mm 61K anti - aircraft autocannon in an open - top rotating armoured turret . The vehicle entered production in February 1945 and was in small - scale production until 1948 . After World War II it became clear that the firepower of a single 37 mm AA gun was not effective against high - speed , low - altitude targets . SPAAGs based on light tank chassis had poor maneuverability in difficult terrain , slow off - road speed and insufficient range in comparison with medium tanks and SPGs . Thus the ZSU - 37s were retired from service by the end of the 1940s . ZSU - 57 - 2 prototypes . For several years after World War II there were no new SPAAG models in the USSR except for the BTR - 152 A ( which were armed with 2 or 4 14 . 5 mm KPV heavy machine gun s ) . Such vehicles were designated ZTPU - 2 or ZTPU - 4 correspondingly and BTR - 40 A ( ZTPU - 2 ) wheeled SPAAGs . Two of the USSR ' s potential enemies – the United States and Great Britain , had high - quality air forces with substantial ground - attack experience . The need for a new tracked AA vehicle was apparent . In February 1946 , the Design Bureau of Works No . 174 in Omsk and the Research Institute No . 58 in Kaliningrad , Moscow Oblast submitted a joint project for a SPAAG based on the T - 34 tank chassis , to be armed with four 37 mm AA guns , to the Technical Council of the Ministry of Transport . However , the project did not proceed due to the desire to concentrate attention on the newest tank chassis available . The Design Bureau of Research Institute No . 58 ( NII - 58 ) ( formerly known as the Central Artillery Design Bureau , TsAKB ) , under the supervision of V . G . Grabin , began the development of a twin 57 mm S - 68 automatic anti - aircraft gun based on the 57 mm S - 60 in the spring of 1947 . The first S - 68 prototype ( with ESP - 76 electric drive ) , was ready in 1948 . It was initially mounted on a S - 79A four - wheel carriage ; that system passed various tests but did not go into production . The final project of the ZSU - 57 - 2 ( Ob ' yekt 500 ) , armed with twin S - 68s and based on a light - weight T - 54 tank chassis , was finished in 1948 . The first prototype ZSU - 57 - 2 was built in June 1950 , the second in December 1950 . After official tests which took place between 27 January and 15 March 1951 in which the vehicle was driven for 1 , 500 km and 2 , 000 rounds were fired from its guns , six more prototypes were built for service tests . These prototypes had some improvements included , such as an increased ammunition load ( 300 rounds ) , but development stopped again due to the absence of improved S - 68A guns . Various updates continued in 1952 and 1953 . The service tests , in which two vehicles participated , took place in December 1954 . This was due to delays in the development of drives for the S - 68 guns . The ZSU - 57 - 2 officially entered service in the Soviet Army on 14 February 1955 . Description . Overview . Based on past experiences with SPAAG designs , Soviet engineers designed a vehicle that used a modified T - 54 chassis , with four twin road wheels per side instead of five , and much thinner armour . The vehicle was armed with twin 57 mm S - 68 autocannon in a new , large , rotating , open - topped turret . The ZSU - 57 - 2 consists of three compartments : driver ' s in the front , fighting in the middle and engine - transmission at the rear . The hull is more spacious in comparison with the T - 54 because of the thinner armour and has different locations for some equipment . The general layout , with transverse mounting of the engine , is the same . Driver ' s compartment . The driver ' s compartment is located on the left hand side of the front of the hull . The driver ' s seat is moved forward and to the left in comparison with its location in the T - 54 . The compartment is equipped with a single - piece hatch cover opening to the left and two periscopic vision devices . One of them can be replaced by the TVN - 1 infrared vision device which is operated together with the infrared headlamp , which is mounted on the right track board . A fire - fighting equipment signal panel and a spare parts case are also located in the driver ' s compartment . Turret . The open - topped box - type welded turret has a ball - bearing race ring 1850 mm in diameter . The turret rear can be removed which makes replacement of the guns easier . The turret can be covered in the travelling position by a tarpaulin which has 16 plexiglass windows . To aim the guns , base data such as the target ' s speed , direction and range must be entered into the sighting system by the sight adjuster , who sits to the left of the guns at the rear of the turret . The target ' s speed and direction is determined by visual estimation , while range can also be estimated visually or with the rangefinder . The upper front of the turret has two small ports with armoured covers meant for collimator s of the sight . To fire the guns , the breeches must first be opened . The left and right loaders , located in the forward part of the turret on both sides of the main armament , load clips into the magazines of their respective weapons . The loaders ' travel seats should be stowed in clamps on the turret sides before opening fire . The gunner , seated on the left hand side in the middle of the turret , aims the gun and opens fire using an electric trigger , common to all barrels , or a pedal , which is individual for each barrel . If manual mechanical drive is used instead of electrohydraulic drive , three crew members instead of two should work with the sight . The commander , who sits on the right hand side in the middle of the turret , aims the gun in azimuth , the gunner aims the gun in elevation and the sight adjuster enters data into the sight . The loaders feed clips into the twin autocannon manually as needed . Armament . The twin S - 68s are recoil - operated and weigh 4 , 500 kg . Their construction was based on two 57 mm S - 60 AA autocannons . The guns have a recoil of between 325 and 370 mm . The individual weapons cannot be swapped from one side to the other as they are mirror images . Each air - cooled gun barrel is 4 . 365 m long ( 76 . 6 caliber ) and is fitted with a muzzle brake . They can be elevated or depressed between −5° and + 85° at a speed of between 0 . 3° and 20° per second , the turret can traverse 360° at a speed of between 0 . 2° and 36° per second . Drive is from a direct current electric motor and universal hydraulic speed gears ( a manual mechanical drive is also provided in case of electrohydraulic failure ; with the use of mechanical drive , elevation speed is 4 . 5° per second and the turret traverse speed is 4° per second ) . The guns are capable of firing up to 210 – 240 fragmentation and armour - piercing tracer rounds per minute , with a practical rate of fire of between 100 and 140 rounds per minute . Muzzle velocity is 1 , 000 m / s . Each clip has 4 rounds , each of which weighs 6 . 6 kg ; the charge in each round consists of 1 . 2 kg of 11 / 7 nitro - cellulose powder , a projectile weighs 2 . 8 kg . Maximum horizontal range is 12 km ( with an effective range against ground targets of up to 4 km / 2 . 5 miles . Maximum vertical range is 8 . 8 km with a maximum effective vertical range of 4 . 5 km / 14 , 750 ft ) . Fragmentation rounds have a safety - destructor which activates between 12 and 16 seconds after being fired so the maximum slant range of anti - aircraft fire is 6 . 5 – 7 km . BR - 281 armour - piercing rounds are able to penetrate 110 mm armour at 500 m or 70 mm armour at 2 , 000 m ( at 90° impact angle ) . The S - 68 autocannon was the most powerful AA gun installed on SPAAGs at that time . According to the statistical data of the Air Defence Research Institute No . 2 , a direct hit of a single 57 mm shell could destroy a contemporary jet aircraft . In order to shoot down a jet bomber of the Canberra type , an average of 1 . 7 hits were deemed necessary . The vehicle carries 300 rounds , and the ammunition is stowed as follows : 176 rounds in clips inside the turret , 72 rounds in clips in the hull front , and 52 separate ( unclipped ) rounds in special compartments under the turret floor . Armour - piercing rounds in clips are placed in the rear part of the turret to the left and right of the guns . Empty shell cases and clips are removed via a conveyor belt through a special port in the turret rear into an external metal wire basket on the back of the turret . Armour protection . The ZSU - 57 - 2 ' s armour is welded rolled steel sufficient to protect the vehicle from 7 . 62 mm armour - piercing bullets at 250 meters . Armour thickness is as follows : Maneuverability . The ZSU - 57 - 2 has a maximum road speed of 50 kilometres per hour , which is reduced to around 30 km / h off - road . The vehicle has better acceleration compared with the T - 54 because of its better power - to - weight ratio ( 18 . 6 hp per tonne ) . It has an operational range of 420 km on roads and 320 km across country . The vehicle can cross 0 . 8 m high vertical obstacles , 2 . 7 m wide trenches , ford 1 . 4 m deep water obstacles and climb 30° gradients . The ZSU - 57 - 2 uses the same engine as the T - 54 . It is a V - 54 12 - cylinder four - stroke V - shaped 38 . 88 litre water - cooled diesel which develops 520 hp ( 388 kW ) at 2 , 000 rpm . The engine itself weighs 895 kg . Fuel capacity is 830 litres carried in three fuel tanks inside the hull ( 640 l total ) and two external fuel tanks on the right fender each of 95 l ; fuel capacity was increased in comparison with the T - 54 . External rear - mounted supplemental fuel tanks can increase the road range to 595 km . The mechanical transmission in the rear part of the hull consists of a change gear quadrant , a multiplate main clutch of metallic contact , a manual gearbox with five forward gears , two multiplate planetary steering clutches with band brakes and two in - line final drive groups . The chassis has four twin rubber - tyred road wheels with individual torsion bar suspension , a rear drive sprocket with detachable sprocket rings ( lantern - wheel gear ) and an idler wheel on each side . The first and last road wheels each have a hydraulic rotary shock absorber . The track is 12 . 33 m long , 580 mm wide and has 90 links ; despite having four road wheels instead of five the ground contact area of the track is the same as the T - 54 ( 3 . 84 m ) . Track center distance is 2 . 64 m The vehicle has a ground pressure of 0 , 63 kg / cm² . Other equipment . The ZSU - 57 - 2 ' s electrical power unit partially differs from the T - 54 , in that it consists of a more powerful G - 74 direct current generator which develops 3 kW ( 108 A at 27 – 29 V ) at 2100 rpm and six 24 volt 6 - STEN - 140M or 6 - MST - 140 accumulator batteries ( total battery capacity is 420 A - h ) , the batteries are used for starting the engine and an electrical power supply when the generator is shut down . The ZSU - 57 - 2 is equipped with an automatic anti - aircraft sight of the plotter type with two collimators which can supervise a target with a speed of up to 350 m / s , a dive angle of between 0° and 90° and a slant range of up to 5 , 500 m ; a simple mechanical sight is provided in case of failure . There is also an optical sight for direct fire at ground targets . The 10RT - 26E portable radio transceiver is located on the right hand side of the turret interior . It has a range of 9 to 20 km when the vehicle is stationary , and from 7 to 15 km when the vehicle is on the move . It was later replaced by R - 113 or R - 113 radio transceivers . The TPU - 4 - 47 intercom system was later replaced by R - 120 or R - 124 intercom systems . Small arms for the crew members include two AK - 47 assault rifles and a 26 mm signalling pistol . Weaknesses . The main weakness of the ZSU - 57 - 2 was the lack of a search or fire - control radar ; the vehicle was equipped with an optical mechanical computing reflex sight as the sole fire control system , so it could engage visible targets only . Night firing was also impractical . Also , the manual gunlaying and manual clip loading was not good enough , the rate of fire is not high enough , particularly considering that air - cooled barrels require quite long pauses for cooling at high rates of fire and the turret traverse is not fast enough to effectively intercept high - speed attack jet aircraft at low altitudes . The vehicle cannot perform aimed fire on the move . Although the ZSU - 57 - 2 had the highest firepower among production SPAAGs of its time , the anti - aircraft fire efficiency of a battery of four vehicles was even lower than that of a battery of six towed 57 mm S - 60 anti - aircraft guns controlled by the PUAZO - 6 anti - aircraft artillery director with the SON - 9 fire control radar or later by the RPK - 1 " Vaza " radar . It became obvious that the hit probability on a jet aircraft of the era was very low using only determination of target speed by aircraft type and determination of distance to the target by eye or by rangefinder ; the ZSU - 57 - 2 was designed to defend tank units against NATO attack aircraft flying at subsonic speeds , but it entered service ten years too late . Aircraft technology had improved to the point that a SPAAG required a much higher rate of fire , turret traverse speeds of 50 – 100° per second and a fully automatic radar - controlled fire control system . Works No . 174 started a modernization programme for the ZSU - 57 - 2 in parallel with the beginning of its serial production in 1957 , but this programme was rejected due to the development of new radar - guided SPAAGs armed with small - bore autocannons and another tracked chassis . The ZSU - 57 - 2 still retained some of the features of its predecessor , the ZSU - 37 . One of them was the lack of an armoured roof on the turret . The advantages of an open turret for SPAAGs , such as very high elevation angle for AA autocannons , excellent visibility of the combat situation by the gunners and no need for induced ventilation of the fighting compartment during intense fire were significantly over - shadowed by the disadvantages . The open turret of the ZSU - 57 - 2 made it vulnerable from above , and prevented operations under NBC conditions . This flaw was partially nullified in modified Bosnian Serb ZSU - 57 - 2s which had improvised overhead armour protection . Nevertheless , its Western counterparts that were operationally available in the 1950s , such as the US M19 GMC ( based on the M24 Chaffee light tank ) and the M42 Duster SPAAGs ( both armed with the famous 40 mm Bofors M2A1 twin AA gun ) and the British Crusader AA SPAAG which was armed with a single 40 mm Bofors AA gun , had similar problems and were armed with less powerful weapons . The M42 Duster was modernized and equipped with a T50 radar system in 1956 ( production of the ZSU - 57 - 2 had not started at this point ) . Production history . Although the vehicle entered service in 1955 and in the same year the No . 174 Works located in Omsk began producing the hulls and turrets , the first vehicles were completed in 1957 after the first 249 57 mm twin S - 68 guns were produced by the Artillery Works No . 946 located in Krasnoyarsk . A total of 5 , 300 of these weapons were produced by the end of the 1950s . The hulls and turrets were produced by No . 174 Works where the final assembly also took place while the Krasnoyarsk Works , belonging to the Ministry of Heavy Engineering , participated in some production stages . The ZSU - 57 - 2 remained in production until 1960 when the No . 174 Works stopped producing the hulls and turrets for ZSU - 57 - 2 . More than 2 , 023 ZSU - 57 - 2 " s " were produced in Soviet Union . 250 ZSU - 57 - 2 SPAAGs based on the Chinese Type 59 ( a copy of the Soviet T - 54A ) tank chassis were produced under license in North Korea . The turrets were bought from the USSR and delivered between 1968 and 1977 . Since the production of the ZSU - 57 - 2 turrets ended in 1960 the turrets that North Korea bought must have come from decommissioned Soviet ZSU - 57 - 2 " s " . The turrets were ordered in 1967 . Service history . Former USSR . The ZSU - 57 - 2 officially entered service with the Soviet Army in 1955 . The first vehicles began replacing BTR - 40A " s " and BTR - 152A " s " in the anti - aircraft batteries of tank regiments in 1957 . It was first shown publicly during the military parade in Moscow on 7 November 1958 . Initially , tank regiments had a single battery equipped with four SPAAGs , later increased to two batteries , each equipped with four SPAAGs . The vehicle was also used by some motor rifle regiments ( which in the 1960s had one battery equipped with four SPAAGs or , more likely , with six 23 mm ZU - 23 towed twin AA guns ) . The anti - aircraft performance of the ZSU - 57 - 2 , however , was quickly found to be unsatisfactory and , because of rapid air force development , the vehicle was deemed obsolete by the early 1960s . ZSU - 57 - 2s were gradually replaced by radar - guided ZSU - 23 - 4 Shilka s at the beginning of 1965 . Towards the end of the 1960s , a frequent configuration was one battery of an AA battalion in a tank regiment equipped with ZSU - 23 - 4s and another battery equipped with ZSU - 57 - 2s . Unpopular in the Soviet Army , the ZSU - 57 - 2 was replaced by ZSU - 23 - 4s by the early 1970s . Most ZSU - 57 - 2s were put into reserve storage while a few remained in service in tank training centres ( as vehicles for driver training ) , until the end of the 1970s . Some were converted by army workshops into bulldozers . The last ZSU - 57 - 2s were scrapped in the 1980s , while some dismantled vehicles were used as gunnery range targets . One is preserved in the Kubinka Tank Museum . Foreign service . ZSU - 57 - 2s were exported like other Soviet equipment . Five other Warsaw Pact members — Poland , East Germany , Hungary , Bulgaria and Romania — used it , as well as Cuba , Egypt , Iran , Iraq and Syria . North Vietnam and North Korea may have received theirs without payment . East Germany . The first foreign operator of the ZSU - 57 - 2 was East Germany as it received its first vehicles in September 1957 . From 1957 to 1961 the National People ' s Army received 129 vehicles , eventually replacing them with ZSU - 23 - 4s between 1967 and 1974 . The ZSU - 57 - 2 was completely gone from East German service by 1979 . Some of the vehicles were converted into FAB 500U training vehicles for T - 54 drivers and were passed on to the unified German state . Poland . Poland received its 129 ZSU - 57 - 2s between 1957 and 1961 . They were also offered a production license for twin S - 68 AA autocannons , but declined it . Eventually , Poland replaced all its ZSU - 57 - 2s with ZSU - 23 - 4s . Seven Polish ZSU - 57 - 2s are preserved , one at the Lubuskie Military Museum in Drzonów , one in Wicko Morskie , the largest anti - aircraft artillery firing range in Poland , one at the Land Forces Museum in Warsaw , one at the History and Tradition of Suvalkai Soldiers Museum in Suwalszczyzna , one in Koszalin and two at the Polish Army Museum in Warsaw . Other Warsaw Pact countries . Three other Warsaw Pact members , Hungary , Bulgaria and Romania , received ZSU - 57 - 2s once the ZSU - 23 - 4 was introduced in the Soviet Army . Czechoslovakia imported one ZSU - 57 - 2 for testing but it was rejected when it was realised that the domestically produced M53 / 59 Praga was comparable to the ZSU - 57 - 2 . Former Yugoslavia . The Socialist Federal Republic of Yugoslavia ordered 100 ZSU - 57 - 2s in 1963 . Deliveries were completed between 1963 and 1964 . They were passed on to the successor states during the 1992 breakup of the federal state . They were then used by the Federal Republic of Yugoslavia . There were 54 of those vehicles in service as of 1999 , but this number decreased to 36 in the subsequent decade ; they were withdrawn from active service by 2003 . However the Yugoslav military still possessed them and after the creation of Serbia and Montenegro they were scrapped . Two vehicles captured by Croatian forces during the Croatian War of Independence and were later also scrapped . Slovenia . The air defence battery of the 44th " Wolfs " armoured - mechanized battalion stationed in Pivka , belonging to the 4th Regional Command Postojna operates ZSU - 57 - 2 " s " . Finland . Finland imported 12 ZSU - 57 - 2 SPAAGs between 1960 and 1961 alongside other kinds of Soviet equipment . The ZSU - 57 - 2 " s " were designated 57 ItPsv SU 57 - 2 , some of them remained in service to the end of the century . A ZSU - 57 - 2M modernization programme was being developed in Finland which would equip the vehicle with radar and configurable ammunition . However , after the prototype was produced the project was abandoned because of high costs . ItPsv SU - 57 " s " were withdrawn from service in 2006 . People ' s Republic of China . The People ' s Republic of China was approached by Iraq in the early 1980s to develop a copy of the ZSU - 57 - 2 system and a few examples were delivered to the PRC for reverse - engineering . To meet Iraq ' s production order , NORINCO attempted to manufacture a copy with the improved amphibious chassis of the Type 69 - II tank . Several Type 80 SPAAGs were tested and accepted into service by the People ' s Liberation Army ( PLA ) in small numbers . It was originally intended for the export market but didn ' t sell well . Greater success was achieved by Chinese - made proximity fuses which could be used to modernize the S - 60 and S - 68 ammunition . Middle East . Iraq ordered 100 ZSU - 57 - 2 " s " in 1970 from Soviet Union and they were delivered between 1971 and 1973 . The New Iraqi Army does not use these vehicles . Iran ordered 100 ZSU - 57 - 2 " s " in 1966 from Soviet Union and they were delivered between 1967 and 1968 . Around 90 remained in service until 2002 . Egypt ordered 100 ZSU - 57 - 2 " s " in 1960 from Soviet Union and they were delivered between 1961 and 1962 . ZSU - 57 - 2s were not very successful during either the Six - Day war in 1967 or the Yom Kippur War in 1973 . Despite that , the Egyptian Army operated 40 ZSU - 57 - 2 " s " as of 2003 and equipped them with radars . Egypt also bought Chinese - made proximity fuzes for its S - 60 and S - 68 ammunition . The Israelis captured a number of ZSU - 57 - 2s from the Egyptians or Syrians . One resides at the Yad La - Shiryon armor museum in Latrun , another at the Israel Defense Forces History Museum in Tel Aviv , and the third ( captured in 1973 ) at the Israeli Air Force Museum in Hatzerim . Cuba . Cuba received 25 ZSU - 57 - 2s alongside other heavy equipment from Soviet forces stationed on the island in 1962 during the Cuban Missile Crisis . They remain in service . Combat use . While primarily an anti - aircraft weapon the ZSU - 57 - 2 was also used in the role of ground support vehicle . Vietnam War . The ZSU - 57 - 2 was used in combat for the first time in the Vietnam War by the Vietnam People ' s Army ( VPA ) , beginning with the Easter Offensive in 1972 . It also saw action during the Ho Chi Minh Campaign in 1975 . Several batteries of ZSU - 57 - 2s were used for the air defence of the 201st and 202nd tank regiments during the Easter Offensive of 1972 . ZSU - 57 - 2s were used by the VPA against US aircraft but it proved to be more effective against ground targets . South Vietnam also used captured ZSU - 57 - 2s . About 500 ZSU - 57 - 2s survived the war . 200 are still in service . Middle East . ZSU - 57 - 2 " s " were used during several conflicts in the Middle East including the Six Day War in 1967 and the Yom Kippur War in 1973 , in both cases by Egypt and Syria . A battery of Egyptian ZSU - 57 - 2 " s " together with T - 34 " s " defended El - Arish airstrip . These were defeated by a company of Israeli M48 Patton MBTs belonging to the 7th Armored Brigade during an intense action on 6 June 1967 . ZSU - 57 - 2s were not generally successful and a number fell into Israeli hands . Syria used ZSU - 57 - 2 " s " during the 1982 Lebanon War during which they unsuccessfully engaged Israeli air force aircraft over the Beqaa Valley . However , the vehicles fared better when used against land targets . During the Iran – Iraq War , ZSU - 57 - 2s were used by both Iraq and Iran . Iraq also used Chinese Type 80s during this conflict and the First Persian Gulf War . Iraqi ZSU - 57 - 2s , which could receive information from the radar on ZSU - 23 - 4 s or 9K31 Strela - 1 ( SA - 9 Gaskin ) / 9K35 Strela - 10 ( SA - 13 Gopher ) surface - to - air missile systems were employed against Iranian AH - 1J SeaCobra attack helicopters . On 16 January 1991 , during the First Persian Gulf War , Iraqi ZSU - 57 - 2s shot down a Tornado GR1 strike aircraft during an attack by four British aircraft on the Iraqi Shaibah air base . The same day in the late evening one more Tornado GR1 was shot down and three other British Tornados were badly damaged by AA fire near Shaibah . ZSU - 57 - 2s were also used in the 2003 Invasion of Iraq . Yugoslavia . ZSU - 57 - 2s saw service during the Yugoslav Wars , usually in light batteries used by Serbs and Montenegrins of the JNA for attacking ground targets . They were used during the war of independence when Croatian forces captured two ZSU - 57 - 2s from the JNA . They were also used in the air defence role in 1999 during the NATO air raids against Yugoslavia when the Yugoslavs operated 54 of these vehicles .