The Marine Corps’ new CH-53K King Stallion heavy lift helicopter rose from Sikorsky’s Palm Beach, Fla., tarmac for the first time Tuesday morning, marking a significant milestone for the program that has suffered delays due to structural deficiencies found during ground testing.
The first flight consisted of about 20 minutes of ground test and taxiing followed by a half-hour flight that tested basic aircraft-to-ground response, control characteristics of the fly-by-wire avionics system in all axes, chief test pilot Stephen McCulley said during a teleconference with reporters on Tuesday.
“We have a significant amount of time on our ground test vehicle and in simulation,” he said. “The aircraft flew just like we expected it to fly from our simulations. There were no surprises.”
The CH-53K is being developed to replace the Marine Corps’ aging CH-53E Super Stallion heavy-lift helicopter. The Marines plan to begin fielding the new helicopter in 2019 to transport troops, equipment and supplies from ship to shore. The service plans to buy 200 CH-53Ks.
Once it enters service, the King Stallion will be the largest single-rotor helicopter in the world. It will be able to carry 27,000 pounds of cargo compared to the 9,000 pounds an E-model can carry, effectively tripling the Marine Corps ship-to-shore lift capacity, said. Col. Hank Vanderborght, the service’s program manager for heavy lift helicopters.
Though momentous for the program, the first flight was delayed by seven months when during ground testing cracks were found in components of the main rotor gear box. Plans were to fly by the end of 2014 and then pushed to spring 2015 as Sikorsky worked to redesign the components.
“We’re a little behind,” Vanderborght said. “But we are still targeting initial operational capability in 2019. We had a seven-month delay because of that issue and also another half-dozen issues also cropped up ranging from electronic boxes to mechanical systems.”
That is to be expected from a clean-sheet development program, especially when dealing with such a huge and technologically advanced helicopter, Vanderborght said. Margin was built into the program in anticipation of findings during ground and flight test that has not yet been exhausted.
Despite the delays, Vanderborght said the CH-53K is configured as an operational aircraft, which will allow for swift and informative initial testing and the follow-on operational evaluation.
“This is the most mature aircraft that we have gone into the first flight with inside the history of naval rotorcraft,” he said. “We have onboard the full functionality of the software … We have over 200 hours of turn time on the ground test vehicle–which is a fully functioning aircraft in itself. We have wrung the systems out quite a bit, both the software and the hardware, on that aircraft.
The aircraft that flew is one of four that will undergo a 2,000-hour, three-year flight test program in preparation for the Marine Corps declaration of initial operational capability in 2019. Aircraft 3 is nearly complete and–once instrumentation is complete–will likely be ready to fly before the end of the year, though that event probably will be scheduled for January, said Michael Torok, Sikorsky’s CH-53K program manager. Aircraft two and four are in assembly awaiting delivery of their gearboxes.
Behind those four aircraft are two aircraft that will be used for operational testing. After those, the line will keep humming to produce two aircraft that will deliver to VMX-22, the Marine Corps’ operational test squadron. Those two aircraft will eventually be retrofitted and enter the fleet as operational helicopters.
Meanwhile, the Sikorsky team will crunch the data from the maiden flight and use that to inform future flights as the test pilots increase speed and open the aircraft’s envelope, Torok said. The aircraft currently is flying in direct mode, a degraded setting of the fly-by-wire controls, which will be activated incrementally in future tests.
“We now have to take the data and go back and compare it to everything we predicted,” Torok said. “Visually the aircraft looks really good…The pacing item won’t be the aircraft; it will be the data itself. We will target to get a flight off every couple of weeks to get another flight off.”