Just to add a little clarification to some of the issues experienced by the H-53E series. The CH-53E experienced multiple MGB failures early in its development and fielding. Most were due to problems with the number 2 engine bull gear input. One occurred at Stratford resulting in a safe landing on a small light house island in Long Island sound. A second one occurred in a west coast Marine squadron once again resulting in a safe landing. Other numerous in flight chip lights and other impending failure indications occurred with no additional problems.
In addition, the E experienced multiple tail rotor drive train failures resulting from the basic design of the system. Like the S-92 the tail rotor drive train of the 53E runs through a box inside the overhead of the cabin and tail transition. Initially this box did not have sufficient drainage to keep the tail drive shaft bearings clean and dry in heavy rains. On one occasion at Stratford a number two engine fuel leak resulted in the tail rotor drive shaft bearings being submerged in fuel. A second Navy MH experienced a failure after flying through a very heavy rain storm in Norfolk, VA. Neither resulted in the loss of a machine. Additional drain holes and lines were incorporated into the design of the tail rotor drive train structure and a bearing monitor system was added.
The swash plate bearing problems did result in the tragic loss of machines and their crews. One was the result of improper maintenance (lack of proper greasing) and one from a faulty assembly delivered from the vender. I believe that a third remains unknown. The diameter of the 53E swash plate is more than 6 feet at the bearing. At this diameter the bearing race velocities are more than 60 fps. Any impending failure results in a very rapid increase in temperature and further damage. As a result, a bearing monitor system was added to help monitor this.
I hope this clears up a few of the misconceptions concerning this magnificent beast.