The U.S. Marine Corps’ CH-53K King Stallion heavy-lift helicopter prototype made its first flight October 27 from the West Palm Beach, Fla., facility of manufacturer Sikorsky Aircraft. The first of four planned engineering development models (EDM) flew for 30 minutes in a ground effect hover up to 30 feet above the ground.

Sikorsky rolled out the helicopter in May 2014, and expected to fly it by the end of last year. But the maiden flight was delayed by problems with the gearbox and other technical issues. The program experienced “a handful of challenges we were working through,” explained Michael Torok, Sikorsky’s CH-53K program vice president, according to Defense News.

“We have entered a much anticipated phase in this developmental program,” said Marine Col. Hank Vanderborght, program manager for heavy-lift helicopters. “We have experienced significant learning at the system and sub-system levels, which continues to build our confidence in the capabilities of the 53K.”  

The EDM-1 helicopter will be joined by three other prototypes over the course of the three-year flight-test program. The Marine Corps program of record for the CH-53K stands at 200 helicopters, with initial operational capability planned in 2019.

The CH-53K is similar in physical scale to its predecessor—the CH-53E Super Stallion—but with the ability to carry a 27,000-pound external load over a mission radius of 110 nm, it offers nearly triple the payload. The King Stallion is powered by three 7,500 shp GE38-1B engines, designated T408-GE-400 by the U.S. Navy.