Street Fight

In September 2010 U.S. President Barack Obama officially announce the end of Operation Iraqi Freedom, prior to the announcement the last U.S. combat troops had left Iraq. However, some 50,000 U.S. troops remained to train and support Iraqi security forces. By December 2011 the last of these U.S. soldiers were also withdrawn, ending finally the presence of large numbers of foreign troops on Iraq soil.

U.S. and allied forces were simply not prepared, nor equipped for this type of conflict and as a result, great efforts were made to address urgent operational requirements by fielding large amounts of new equipment, such as several thousand wheeled armoured patrol vehicles, known by the U.S. Army as MRAPs (Mine Resistant Ambush Protected). In addition to this, in service equipment was upgraded or modified in order to make it suitable to fight the insurgency and in the case of the M1 Abrams main battle tank, vehicles deployed to Iraq were fitted with Tank Urban Survivability Kits (TUSK) in order to make them suitable for operations against insurgents in urban terrain.

The Ml Abrams MBT is the main weapon system of the armoured battalions of the U. S. Army, the Army National Guard and the United States Marine Corps. Initially fielded in the early 1980s, the Ml Abrams made its combat debut during the 1991 Gulf War. From 1996 onwards Ml Abrams of the U.S. Army operated with IFOR and SFOR in Bosnia and from 1999 onwards in Kosovo with KFOR. Since entering service the Abrams has been upgraded several times and currently looks likely to stay in service for several more decades.

While the most modem version of the tank is the M1A2 Abrams SEP V2 (System Enhancement Package Version 2), the bulk of the over 500 MBTs fielded under Operation Iraqi Freedom were of Ml A1 HA/HA+, M1A1 AIM (Abrams Integrated Management) and Ml A2 SEP (System Enhancement Program) standard. The Ml Abrams had originally been designed to battle Warsaw Pact armour in open countryside on German soil, in case that the “Cold War” would have turned hot. Main development criteria for the vehicle had been a high degree of armour protection over the front arc, great firepower and high mobility (speed, cross country capability and agility).

Urban Operations

In the seventies and eighties, when the Ml Abrams was developed, nobody could have foreseen that the MBTs would see extensive action in an asymmetric conflict scenario, in which they would be used to fight insurgents in an urban environment. In Iraq the U.S. Army used the Ml Abrams MBTs regularly to support dismounted troops during combat in urban terrain, for example during the second Battle of Fallujah in 2004 or the fighting in Sadr City in 2006.

These operations were not without losses, with several M1 Abrams MBTs victims to IED attacks, and others knocked out by hand held anti-tank weapons or even simpler means such as petrol bombs. Tank crew members were killed by small arms fire or the effects of IED blasts, when operating with hatches open. Tanks in the streets of the Iraqi cities were facing an increased 360° threat with enemy fighters armed with hand held antitank weapons engaging the tanks from above, or from the rear. Mines and massive IEDs also caused losses. In addition to this the tank crews were not able to use standard tactical procedures that in suitable terrain would have saved them and their vehicle from being hit. The narrow and often angled streets did not allow them to use the mobility of their vehicles to move out of potential kill zones, while the lethality of the tanks was reduced due to the fact that the elevation levels of the weapon systems of the Abrams were limited. In addition to this the visibility of the crews was limited when operating with closed hatches and communication between dismounted troops and the tank crew could only archived by radio.

TUSK Programme

In order to address the issues, the U.S. Army initiated the Tank Urban Survivability Kit programme in 2004, that was first announced officially to the greater public in March 2005. General Dynamics Land Systems (GDLS) was selected as main contractor for the programme, while Rockwell Collins, Raytheon Network Centric Systems and DRS Technologies among others functioned1 as sub-contractors. The aim of the TUSK programme was to improve the survivability, lethality and situational awareness of the Ml Abrams MBTs and their crews when operating in urban areas.

Development of the TUSK components was conducted in a joint effort by the defence industry and the Program Executive Office Ground Combat Systems PEO GCS). In several cases the development of TUSK components was inspired by systems that were already used by other nations, for example in Israel on the Merkava III and IV tanks. The Israeli tanks feature a 12.7mm machine gun mount on the barrel of the main gun, which in case of the TUSK programme was introduced as Counter Sniper/Anti-Material Mount. For time and cost reasons commercial off-the-shelf-items or systems designed under other procurement programmes were chosen and integrated into the TUSK programme whenever possible and then modified for use on the Ml Abrams MBTs.

Under the TUSK programme three different types of kits were developed initially, namely TUSK I, TUSK II and TUSK III. Most components of all three kits could be fitted to all MlA1 Abrams variants as well as to Ml A2 SEP Abrams. The TUSK I kit is the basic variant. Mounting of TUSK II further increased armour protection levels, especially from the effects of Explosive Formed Penetrator IEDs, while the TUSK III kit featured a remote controlled weapon station that is installed on the turret roof. Under Operation Iraqi Freedom the M1A1 Abrams variants were mainly fitted with the TUSK I kit, while the M1A2 SEP Abrams were fitted with TUSK I and TUSK II kits. To the best of my knowledge the TUSK III was not fielded in Iraq. Fitting of the TUSK I kit to an Ml AI AIM Abrams MBT takes approximately 12 hours.

Tusk 1

Due to a briefing of the PEO GCS, dated 2007 the TUSK I kit includes the following components: Abrams Reactive Armor Tiles I (ARAT I) -Explosive reactive armour mounted to the side skirts of the tank consisting of XM19 Explosive Reactive Armour (ERA) tiles. ARAT I increases the side protection by far, especially against attacks with anti-tank weapons. The ARAT I tiles contain an insensitive high-energy explosive.

Loader’s Armour Gun Shield (LAGS) — Shield mounted to the MG of the loader and armoured wall running around the loader’s hatch. LAGS provides vital protection to the loader when operating the loaders machine gun, by the use of the ballistic protected glass the situational awareness of the loader is maintained.

Loader’s Thermal Weapon Sight (LTWS) — AN/PAS 13 Light Thermal Weapon Sight fitted to the loader’s machine gun. The system has a detection range of 550m, is 324mm long, 83mm wide and 112mm high. It has a weight of 1.4 kg and is mounted on the Mil-STD-1913 Picatinny rail of the M240B MG.

With the LTWS the loader gains the capability to identify and engage targets in day, night or conditions of low visibility. Via a cable and a video output the captured images are broadcasted to a Helmet Mounted Display (HMD) that can be fitted to the right or left side of the front of the Tank Crew Helmet of the loader. Originally the AN/PAS 13 LTWS and the HMD were developed under the Land Warrior Program.

Tank Infantry Phone (TIP) -Mounted to the rear of the vehicle on the right side. The TIP is basically an additional Full Function Crew Station (FFCS) that has been added to the AN/VIC-3 vehicle intercom system. The FFCS provides the user with access to all communication capabilities of the Ml Abrams. Access is only limited by the programming of the Master Control Station, he can talk to the tank crew or even use/monitor the radios of the MBT.

Power Distribution Box (PDB) -Mounted inside the turret to the left of the main armament. Being a switch box the PDB provides power for several subsystems of the TUSK such as the LTWS and the Xenon Spot Light as well as the RFS of the CS/AMM. The PDB features seven power outlet sockets.

Driver’s Vision Enhancer (DVE) -Thermal sight for the driver. It consists of the Sensor Module (SM) and the Display Control Module (DCM). For operations at night and under low visibility the driver can replace the centre periscope of the driver’s hatch with the DVE. The DVE allows the driver to see at night and through dust and smoke clouds.

Counter Sniper/Anti Material Mount (CS/AMM) — Allows mounting a 12.7mm M2HB machine gun onto the 120mm M256 smoothbore cannon of the tank which then serves as a second coaxial weapon. The CS/AMM is manufactured by Gunmasters Defense Systems LLC. It enables the crew to engage enemy snipers, RPG-Teams, IED/VBIEDs or other targets up close or out to a range of 2,000m. Aiming of the weapon is done by use of the MBT’s fire control system, allowing high accuracy and reducing collateral damage. The machine gun of the CS/AMM can be fired simultaneously with the main gun and/or the coaxial machine gun. The CS/AMM comes with a ammo can holder that can hold 200 round 12.7mm1 ammo cans. Fitted on the right side of the CS/AMM is a 24-28 VDC Xenon Spot Light.

Remote Thermal Sight (RTS) — The RTS is a 2nd Generation un-cooled thermal sight that is mounted coaxially to the left of the commander’s 12.7mm M2HB machine gun. The RTS is only mounted to M1A1 Abrams variants and not to Ml A2 SEP Abrams. By fitting of the RTS the tank commander is given his own thermal sight. The picture that is generated by the RTS is displayed in the Display Control Module that is mounted to the front of the commander’s station.

Abrams Belly Armor — V-shaped add-on armour mounted beneath the vehicle, offering enhanced protection from anti-tank mines and under floor detonations of IEDs. Mine Resistant

Driver Seat — New driver seat offering protection from the blast effects of mines, being suspended from the roof of the hull, also designated as Driver’s Harness System Seat.

Tusk 2

Due to the same document the TUSK II kit includes the following components:

Abrams Reactive Armor Tiles II (ARAT II) — Explosive reactive armour mounted to the turret sides and the side skirts of the vehicle featuring XM32 Explosive Reactive Armor Tiles. The tiles are mounted directly to the turret and onto the XM19 ARAT I tiles on the side skirts. The ARAT II tiles resemble the shape of roof tiles and are mounted angled facing slightly downwards. ARAT II is fitted as counter IED enhancement.

Rear Camera — A camera mounted close to left tail light of the tank. The pictures captured by it are shown on a display in the driver’s compartment as well as on the Commander’s Display Unit. The system enhances the situational awareness of the driver and allow him to reverse the vehicle in combat situations without guiding instructions from the loader or tank commander. The camera features a thermal channel and a daylight channel. The system is manufactured by BAE Systems.

With the introduction of the TUSK kits the lethality and survivability of the M1 Abrams MBT and situational awareness of the tank crews was improved by far. The co-operation of the vehicle crew with dismounted assets has been made easier. The TUSK adds several tons to the combat weight of the Ml Abrams MBT, which results in greater wear and tear of the automotive parts, and the belly armour reduces ground clearance, the impact of which is of no great importance when it is taken in account that the TUSK was fitted to the M1 Abrams MBTs to make the vehicle fit for military operations in urban terrain. Crews also reported to the author whilst visiting U.S. forces in Iraq, that the extra weight has very little effect on the vehicle speed and acceleration.

360° Shield — Shield system including transparent armour, running around the commander’s hatch. The armour provides increased protection for the vehicle command while at the same time it increases his situational awareness.

Ammunitions

Under a separate procurement programme the Ml028 Canister round was also introduced in order to improve the firepower of the Ml Abrams MBT when fighting in urban terrain and facing groups of dismounts. The Ml 028 Canistt round was originally developed based on a requirement issued by the Commander in Chief U.S. Army Korea, which stated that the U.S. troops based in the Korean theatre needed a short range (100 to 300m) tank fired anti-personnel cartridge. The round is a type of shot gun round for the 120mm smoothbore gun and features an aluminium can as projectile that contains 1,100 tungsten balls. It went into production in 2004 and in Iraq was used with devastating effects against insurgents. In addition to being very effective against groups of dismounts, the Ml 028 Canister round also is extremely effective against block stone walls, concertina wire and soft skinned vehicles such as cars and trucks.

In Iraq the M1 Abrams MBTs carried a mix of M830 HEAT-MP-T (top), M830A1 HEAT-MP-T (centre) and M1028 Canister rounds (bottom).

Armour

Below: the ARAT II tiles resemble roof tiles and are mounted angled, facing slightly downwards. Bottom: the Abrams’ ERA can be mounted to the turret sides and side skirts. In the case of the side skirts the XM32 ERA tiles are mounted onto the ARAT I ERA.

Communications

Below: the TIP is basically an additional Full Function Crew Station (FFCS) that has been added to the AN/VIC-3 vehicle intercom system. It features a handset and a 7.5m long extension cable that can be used by troops outside of the vehicle.

Bottom: here the Tank Infantry Phone (TIP) can be seen in use. The TIP provides dismounted troops access to all communication capabilities of the Ml Abrams MBT and allows easy communication with the crew of the vehicle.

Tusk

Above left: fitting of the Loader’s Armour Gun Shield (LAGS) and the Loader’s Thermal Weapon Sight (LTWS) allows the loader to operate his machine gun while staying low and behind cover. Via a cable and the video output of the AN/PAS 13 Light Thermal Weapon Sight the captured images are broadcasted to a Helmet Mounted Display (HMD) attached to the Tank Crew Helmet of the loader.

Above right: view onto the roof of ttie turret of a Ml A1 HA Abrams MBT fitted with the TUSK I kit. Clearly visible are the Remote Thermal Sight (RTS) and the Loader’s Armour Gun Shield (LAGS). Note the cable channel on the roof that runs from commander’s cupola down to the Counter Sniper/Anti Material Mount (CS/AMM) and houses the power supply for the 24-28 VDC Xenon Spot Light.

Above left: the 360° Shield system for the M1A1 Abrams variants differs in many ways from that for the M1A2 SEP Abrams variant. However, both feature the Commanders’ Spotlight and the Commander’s M4 Bracket. The shields have to differ os the Ml A1 Abrams variants and the Ml A2 SEP Abrams variant feature different mounts for the commander’s machine gun.

Above & below far right: different 360° Shield systems were fielded for the Ml A1 Abrams variants and the Ml A2 SEP ABrams, here the one for the later can be seen. The 360° Shield system includes transparent armour and runs around the commander’s hatch. It provides increased protection for the vehicle command while at the same time it increases his situational awareness.

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