The program successfully passed Defense Acquisition Board (DAB) review and achieved a Milestone C decision that enables low rate initial production funding.
Production is expected to begin at Sikorsky's facility in Stratford, Connecticut in June 2017.
The CH-53K can carry 27,000 pounds, triple that of its predecessor to meet future requirements like carrying the 16,000-pound range Oshkosh JLTV that replaces the 5,500 pound GM Humvee.
The 12-inch wider internal cabin enable carriage of multiple US Air Force standard 463L pallets. It can carry up to three independent external loads at once.
The four prototype helicopters have achieved over 400 flight hours, since maiden flight in October 2015.
It features new GE engines, advanced glass cockpit and composite rotor blades that improve hot and high performance.
The full authority fly-by-wire flight controls and mission management system reduce pilot workload and enable the crew to focus on mission execution as the King Stallion all but "flies itself.
Other features include advanced stability augmentation, flight control modes that include attitude command-velocity hold, automated approach to a stabilized hover, position hold and precision tasks in degraded visual environments, and tactile cueing that all permit the pilot to focus confidently on the mission at hand.
Marine Corps plans to induct up to 200 CH-53K aircraft by 2029, cost around $131 million each. The first six of the 200 are under contract and scheduled to start delivery next year to the USMC.
Two additional aircraft, the first LRIP aircraft, are under long lead procurement for parts and materials, with deliveries scheduled to start in 2020.
The Marine Corps intends to stand up eight active duty squadrons, one training squadron, and one reserve squadron to support operational requirements.
It is powered by three General Electric GE38-1B turboshaft engines, rated at 5600 kW each.