March 9, 2012: The U.S. Marine Corps has 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 V-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 are short of cash.

Five years ago the marines began working on an updated version of the CH-53E (which entered service in the early 1980s): the CH-53K. The first CH-53Ks will not enter service until 2018. Technical problems were blamed but it was later revealed that the marines didn't want to take money away from their MV-22 program to keep the CH-53K program on schedule.

The CH-53K is sixteen percent heavier (at 42.3 tons) than the CH-53E and able to carry nearly twice as much (13.5 tons). The CH-53K will be much easier to maintain and cost about half as much per flight hour to operate.