The U.S. Marine Corps’ newest helicopter, the CH-53K, completed its first external load flight test carrying a 20,000 lb. load May 26 at Sikorsky Aircraft Corporation’s Development Flight Center in West Palm Beach, Fla.

Envelope expansion tests will continue with incrementally increasing speeds with the 20,000 load, and then on to the CH-53K’s requirement, a 27,000-lb. external payload.

The first two CH-53K heavy lift helicopters achieved their first flights on October 27, 2015, and January 22, 2016, respectively. To date these helicopters have achieved over 50 flight hours combined including one flight at speeds over 140 knots.   The third and fourth King Stallion aircraft will join the flight test program this summer.

As the King Stallion flight test program proceeds, both of the current flying aircraft will be exercised to expand the external load envelope. Initial external payloads weighing 12,000 pounds will be flown first in hover and then incrementally to speeds up to 120 knots.  The aircraft will then carry 20,000 and 27,000 pound external payloads.

The CH-53K King Stallion is   a large, heavy-lift cargo helicopter currently being developed by Sikorsky Aircraft for the United States Marine Corps (USMC). The design features three 7,500 shp(5,590 kW) engines, new composite rotor blades, and a wider aircraft cabin than previous CH-53 variants. It will be the largest and heaviest helicopter in the U.S. military.