materials, harsh angles, and flat surfaces found only in stealth jets. Low observable versions of the Black Hawk have been studied as far back as the mid-1970s. In September 2012, Sikorsky was awarded a Combat Tempered Platform Demonstration (CTPD) contract to further improve the Black Hawk's durability and survivability. The company is to develop new technologies such as a zero-vibration system, adaptive flight control laws, advanced fire management, a more durable main rotor, full-spectrum crashworthiness, and damage tolerant airframe; then they are to transition them to the helicopter. Improvements to the Black Hawk are to continue until the Future Vertical Lift program is ready to replace it. In December 2014, the 101st Airborne Division began testing new resupply equipment called the Enhanced Speed Bag System (ESBS). Soldiers in the field requiring quick resupply have depended on speed bags, bags filled with items airdropped from a UH-60. However, all systems were ad hoc with bags not made to keep things secure from impacts, so up to half of the airdropped items would be damaged upon hitting the ground. Started in 2011, the ESBS sought to standardize the airdrop resupply method and keep up to 90 percent of supplies intact. The system includes a hands-free reusable linear brake and expendable speed line and multipurpose cargo bag; when the bag is deployed, the brake applies friction to the rope, slowing it down enough to keep the bag oriented down on the padded base, a honeycomb and foam kit inside to dissipate energy. The ESBS not only better protects helicopter-dropped supplies, it allows the Black Hawk to fly higher above the ground, up from 10 feet, while traveling , limiting exposure to ground fire. Each bag can weigh and up to six can be deployed at once, dropping at . Since supplies can be delivered more accurately and the system can be automatically released on its own, the ESBS can enable autonomous resupply from unmanned helicopters. Design The UH-60 features four-blade main and tail rotors, and is powered by two General Electric T700 turboshaft engines. The main rotor is fully articulated and has elastomeric bearings in the rotor head. The tail rotor is canted and features a rigid crossbeam. The helicopter has a long, low profile shape to meet the Army's requirement for transporting aboard a C-130 Hercules, with some disassembly. It can carry 11 troops with equipment, lift of cargo internally or of