CAMP BASTION, Afghanistan -- The triple-digit temperatures that routinely plague service members here may soon become a memory for the pilots and aircrew of Marine Heavy Helicopter Squadron 361, thanks to an innovative system designed to keep the Marines cool during even the hottest days.
The squadron received 77 Micro-climate Cooling Unit Systems, which are vests Marines can wear that circulate coolant around their bodies, keeping core temperatures down and concentration and energy levels up. The squadron has successfully used these vests on several missions since arriving in July.
How does it work? A micro climate unit, which is a self-contained vapor compression system mounted inside the aircraft that uses environmentally-friendly refrigerants, circulates a chilled liquid through a flexible, insulated tube, known as an umbilical cord, to a vest worn by a Marine over the flight suit and underneath body armor. After the liquid – a mixture of distilled water and cleaning chemicals – travels through the labyrinth of small tubes in the vest, it passes back through the MCU, which uses its 327 watts of cooling power to remove heat from the liquid. This system can circulate liquid as cold as 65 degrees in temperatures up to 125 degrees.
The MCU is a permanent fixture in the aircraft, but the umbilical hose and the vest both detach from the system. Marines can easily disconnect the hose at the end of each flight, or can break it away from the MCU during emergency egress situations with minimal force.
Marines can adjust the temperature of the coolant by using the control bypass assembly to control how fast the MCU circulates liquid through the system.
"Most of the time I use it I have to start with it set low and then slowly turn it up as the flight goes and the cabin gets hotter," said Sgt. William Rogers, a crew chief with HMH-361. "It can actually feel too cold if you crank it all the way when you start your flight."
The system received high approval rates from Marines with HMH-464 who tested it in Africa, and has since become a fully-approved modification for CH-53E Super Stallion helicopters. It can extend mission times from about two hours to more than five hours while working in heat-trapping helicopters, according to tests conducted by the military. This means crews fulfilling assault support requests during the hottest parts of the day can now operate more effectively for longer periods of time.
"It’s a great upgrade for operating in hot environments, especially on extended missions or when we are carrying cargo internally, which causes a lot of exhaustion," said Gunnery Sgt. Brian Cox, a crew chief with HMH-361. "I came back with a dry shirt the first time I used the system – that was a first."
Cox said the vest added no noticeable weight and did not restrict his mobility or range of motion – not surprising since it is constructed of a light-weight cotton fabric.
It is still easy for me to move around the cabin," said Cox.
This highly-anticipated system is more than just a way to keep Marines comfortable while flying. In a region where debilitating temperatures can be as threatening as insurgents, the MCUS serves as a valuable tool to keep Marines’ minds off the heat and focused on supporting the International Security Assistance Forces’ mission in Afghanistan.