has to do is keep the reticle on the target and fire to achieve a hit. Proper lead and gun tube elevation are applied to the turret by the computer, greatly simplifying the job of the gunner. The fire-control system uses this data to compute a firing solution for the gunner. The ballistic solution generated ensures a hit percentage greater than 95 percent at nominal ranges. Either the commander or gunner can fire the main gun. Additionally, the Commander's Independent Thermal Viewer (CITV) on the M1A2 can be used to locate targets and pass them on for the gunner to engage while the commander scans for new targets. If the primary sight system malfunctions or is damaged, the main and coaxial weapons can be manually aimed using a telescopic scope boresighted to the main gun known as the Gunner's Auxiliary Sight (GAS). The GAS has two interchangeable reticles; one for high-explosive anti-tank (HEAT) and multi-purpose anti-tank (MPAT) ammunition and one for armor-piercing fin-stabilized discarding sabot (APFSDS) and Smart Target-Activated Fire and Forget (STAFF) ammunition. Turret traverse and main gun elevation can be performed with manual handles and cranks if the fire control or hydraulic systems fail. The commander's M2HB .50 caliber machine gun on the M1 and M1A1 is aimed by a 3× magnification sight incorporated into the Commander's Weapon Station (CWS), while the M1A2 uses the machine gun's own iron sights, or a remote aiming system such as the Common Remotely Operated Weapon Station (CROWS) system when used as part of the Tank Urban Survival Kit (TUSK). The loader's M240 machine gun is aimed either with the built-in iron sights or with a thermal scope mounted on the machine gun. In late 2017, the 400 USMC M1A1 Abrams were to be upgraded with better and longer-range sights on the Abrams Integrated Display and Targeting System (AIDATS) replacing the black-and-white camera view with a color sight and day/night thermal sight, simplified handling with a single set of controls, and a slew to cue button that repositions the turret with one command. Preliminary testing showed the upgrades reduced target engagement time from six seconds to three by allowing the commander and gunner to work more closely and collaborate better on target acquisition. Mobility Tactical The M1 Abrams's powertrain consists of an AGT1500 multifuel gas turbine (originally made by Lycoming, now Honeywell) capable of at 30,000 rpm and at 10,000 rpm and