In 1996, the USMC launched the H-1 program in cooperation with the Bell company. The H-1 program was a plan to upgrade and modernize the Navy's existing fleets of AH-1 and UH-1 helicopters, in order to extend their service life and lower future operating costs. This was achieved by developing a new version of each helicopter model respectively. The new AH-1Z Viper, also known as "ZuluCobra", received upgraded avionics, fire control systems, engines and an improved four-blade rotor system, among other improvements. Furthermore, both the new Viper and UH-1Y were designed in a way to use mostly identical parts, achieving the desired reduction in operating costs and ease of maintenance as a result. The AH-1Z Viper conducted its maiden flight in December 2000, with three prototypes being built for testing in 2002. Small-scale production began in 2003 before the Viper was approved for full-scale production in November 2010. The USMC has ordered for 189 Vipers to be delivered to the fleet by 2021, with only a few dozen machines being in service today.