Sikorsky's second CH-53K King Stallion helicopter has joined the flight test program for the future U.S. Marine Corps aircraft and achieved first flight.

Sikorsky, a subsidiary of Lockheed Martin, said first flight of the second heavy lift helicopter occurred in late January and that the first and second aircraft have performed more than over 35 flight hours combined, including multiple flights with an active duty USMC pilot at the controls.

The first engineering and development model has achieved flight envelope expansion to 120 knots.

"Adding a second aircraft into flight status signifies another milestone for the CH-53K program," said Mike Torok, Sikorsky's vice president of CH-53K Programs. "With both aircraft in flight test, our flight envelope expansion efforts will accelerate as we continue to make good progress toward our initial operational test assessment and full aircraft system qualification."

Two additional aircraft will join the program this year for three years of testing.

"It is exciting to have two CH-53K helicopters flying," said Col. Hank Vanderborght, U.S. Marine Corps program manager for Heavy Lift Helicopters. "Our program continues on pace to deploy this incredible heavy lift capability to our warfighters."

The CH-53K King Stallion retains similar physical dimensions of its predecessor -- the CH-53E -- but more than triples the aircraft payload to 27,000 pounds over 110 nautical miles under "high hot" ambient conditions.

Features of the CH-53K include a glass cockpit; fly-by-wire flight controls; fourth-generation rotor blades with anhedral tips; a low maintenance elastomeric rotor head; upgraded engines; a locking, United States Air Force pallet compatible cargo rail system; and external cargo handling improvements.

The U.S. Department of Defense's program of record is for 200 of the aircraft.