Sikorsky has recently been awarded a $435 Million Dollar contract from the US Navy. This New contract is an add on the the already 3.5 Billion Dollar COntract awarded to Sikorsky in 2006 to produce four CH-53K Prototypes for evaluation.

More information can be found in the link

http://www.flightglobal.com/news/articles/sikorsky-awarded-435-million-contract-for-four-ch-53k-test-aircraft-386555/

sorry about that, diddnt realise that there was already a thread about the 53K

On Wednesday October 28, 2015 at the Sikorsky Aircraft Development Flight Center the successful first flight of the U.S. Marine Corps’ CH-53K King Stallion heavy lift helicopter prototype, known as Engineering Development Model-1 (EDM-1). The 30-minute flight signals the beginning of a 2,000-hour flight test program using four test aircraft.

Another big maintenance hog.

Did Sikorsky ever fix the EGR problem?