In late 2020 the U.S. Marine Corps increased its initial order for its new CH-53K King Stallion helicopters by six, increasing the initial production order to 24. All 24 will be delivered between 2021 and 2024. As the “K” implies this is the latest version of a heavy-lift helicopter that has been in service since the 1960s. The marines thought they would have developed a successor to the CH-53 by now but the manufacturer continued to upgrade existing models that kept ahead of potential replacements.
In 2014 the marines ordered the first four production model CH-53Ks for testing and evaluation. Each one cost $109 million. Later production models will cost under $100 million. The first four began arriving in 2016. In 2017 testing began and problems were encountered that delayed deliveries to the marines a year to 2019 and eventually to 2021.
In 2007 the marines began working on an updated version of the CH-53E, a model that entered service in the early 1980s. The new CH-53K was designed to be much easier to maintain and cost about half as much per flight hour to operate.
The marines want to buy 200 CH-53Ks, for about $115 million each, which includes over a decade of development costs. Development took so long because the marines did not have enough cash to keep building the new V-22 while also keeping CH-53K development on schedule. Technical problems were blamed for the CH-53K delays but it was later revealed that the marines didn't want to take money away from their MV-22 program in order to keep the CH-53K program on schedule. It’s all about limited resources and aging equipment.
The CH-53K is a 34-ton helicopter with a payload of up to 15.8 tons internally or 16.3 tons externally (suspended under the helicopter. The cargo bay can hold up to six wooden pallets, five Half 463L Pallets or two Full size 463L Pallets. Three 3,000-liter (800 gallon) fuel containers can be carried for use in aerial refueling or delivery to ground forces. The 53K is also equipped to be refueled in the air. Up to 30 troops can be carried or 24 casualties on litters. The cargo load is nearly twice that of the CH-53D. Cruising speed is 310 kilometers an hour and endurance is about 2.8 hours. Combat radius is 200 kilometers and max range is 460 kilometers. Max altitude is 4.900 meters (16,000 feet).
In 2012 the marines finally retired the last of its CH-53D transport helicopters. Introduced in the late 1960s, 124 were built before production stopped in 1972. The CH-53D was to be replaced by 348 MV-22 Osprey tiltrotor aircraft. But delays in that program, and a reduction in the number of V-22s to be built, led to the CH-53K. While the CH-53K is a better cargo hauler, the MV-22 moves twice as fast and the marines have found that to be a major advantage in combat. But the MV-22 is more expensive to operate and the marines cannot afford to buy and operate all the MV-22s they need to replace older helicopters. That led to more upgrades for existing CH-53s and the need for a new model.
Periodic upgrades are the norm for military aircraft. For example in 2013 the U.S. Navy began equipping 40 of its CH-53E transport helicopters with lightweight armor kits that provide protection from bullets and shell fragments. This feature is also available for the 53K. This CSA (Critical Systems Armor) uses lightweight materials like composites and only protects areas of the helicopter known to be critical. These modular vehicle/aircraft composite armor systems have become increasingly popular since the 1990s, for both helicopters and low flying fixed wing aircraft like American AC-130 gunships. Flying low, aircraft are vulnerable to damage from rifles and machine-guns, especially the larger caliber 12.7mm and 14.5mm models. If a bullet hits one of the crew or a vital component the aircraft can be lost, or at least forced to abort its mission.
Modern helicopters are also equipped with systems that automatically detect approaching heat-seeking missiles and deploy countermeasures. There are also systems that detect and locate the source of ground fire from automatic-weapons. Another area of constant upgrades is the cockpit where easier to use controls are always being developed as well as sensors for navigation. Military equipment not only has to deal with age but also obsolesce. That means you either evolve or die.