The U.S. Marine Corps recently lost one of their two K-Max cargo helicopter UAVs in Afghanistan. On June 5th one of them came in hard during a landing and was heavily damaged. It has to be shipped back to the United States to be rebuilt. This came after nearly two years of trouble-free use and over 1,300 missions. UAVs have higher accident rates than manned aircraft and helicopters are more prone to accidents than fixed wing aircraft, so this one accident does not lessen marine enthusiasm for delivering supplies via helicopter UAVs. The marines are trying to get funding to buy 16 K-Max UAVs, so that in situations where road travel is dangerous, they can supply bases and outposts with K-Max, which is the cheapest form of air transport for this sort of thing.
Last year the marines twice extended the time two K-Max UAV helicopters would remain in Afghanistan. That was to last until March, 2013 but then the K-Maxs were extended again. This was all because the two unmanned transport helicopters have proven very useful. For example, a year ago it was demonstrated that K-Max could handle having cargo hooked up to a sling while the K-Max was hovering. This is called a hot hookup and, when done with a manned helicopter, you have the pilots and a crew chief supervising the operation from the helicopter. This sort of thing was considered too difficult for a remotely operated helicopter but that was not the case. Now the marines have shown that the K-Max is capable enough to handle it just using the remote operators and the UAVs flight control software.
The U.S. Marine Corps have been testing the K-Max in Afghanistan since late 2011, and in December of that year K-Max made its first cargo flight, taking 90 minutes to deliver 1.5 tons of supplies to a distant outpost. Since then the two K-Max UAVs in Afghanistan have delivered over 2,000 tons of cargo and spent nearly 2,000 hours in the air. The arrival of a K-Max has become a normal event for many remote marine bases in Afghanistan.
The marines began looking for a cargo carrying helicopter UAV in 2009, and quickly determined that K-Max was the best candidate for further development and testing. The K-Max in Afghanistan are there as a final test of how useful the vehicle could be in a combat zone. An unmanned cargo helicopter risks fewer lives and is cheaper to operate. It can also be used in extremely hazardous missions.
The K-Max UAV was originally designed as a single seat helicopter that could carry sling loads of 2.8 tons (6,000 pounds) at sea level, or two tons (4,300 pounds) at 4,800 meters (15,000 feet). The 5.5 ton K-Max has a cruise speed of 185 kilometers an hour and can stay in the air for up to 2.6 hours per sortie. One of the most attractive features of the K-Max is the amount of automation in the aircraft. The flight control software can be programmed with where to take and drop a cargo, then return and land automatically. The operator can intervene at any time, but most of the time the operator just monitors vidcams attached to the K-Max to ensure nothing goes wrong.
In 2010, the U.S. Army conducted tests using a K-Max to deliver supplies via parachute. This involved using the army low altitude parachute, which can drop loads of 36 kg (80 pounds) to 273 kg (600 pounds). The K-Max had a special rig that could carry and release four different payloads and demonstrated its ability to drop each one at a different location. The low altitude drops are more accurate than higher altitude ones and useful where the troops getting the stuff are on hilly ground that has few good helicopter landing zones. The army also tested K-Max dropping loads from higher altitudes, using GPS guided parachutes. The army and marines are planning to have their helicopter UAVs to drop supplies via parachute to troops in isolated areas. The army has managed to make this work but because of looming budget cuts is not proceeding any further.