Sikorsky CH-53K programme puts gearbox issues behind it

US Naval Air Systems Command (NAVAIR) appears to be confident that the Sikorsky CH-53K programme has put the gearbox failures and parts delays experienced prior to first flight in October 2015 behind it, but the Lockheed Martin-owned helicopter manufacturer won’t receive bonus cheques for lateness.

The US Government Accountability Office (GAO) recently stated that the King Stallion’s planned entry into low-rate production has been delayed eight months to February 2017 because of technical difficulties.

The aircraft is being developed for the US Marine Corps to replace the heavy-lift CH-53E, and should be ready for duty in 2019.

Although the US government bears the ultimate cost of delays and overruns, NAVAIR says schedule incentives were part of the arrangement “and Sikorsky was impacted due to schedule slides”.

The latest development cost estimate stands at $6.8 billion, $2 billion more than originally imagined.

Sikorsky/Lockheed Martin

The super-heavy-lift helicopter’s two critical technologies are the split torque gearbox and seven anhedral swept-tip composite main rotor blades and both are now flying on the first two engineering design model (EDM) aircraft. However, problems reported with the main gear box did set back the overall test schedule by delaying first flight.

“The redesigned components are flying in the test aircraft and are performing well,” confirms NAVAIR in an email to Flightglobal. “The redesigned components are flying in both test assets currently flying, and no further changes are anticipated. There has been no impact to the flight schedule because the changes were made prior to first flight.”

The programme has also been working with unnamed suppliers to “find efficiencies” and all redesigned components were ground testing prior to retrofit and flight on EDM-1. NAVAIR expects the third and fourth aircraft to join the test campaign “before the end of summer 2016”.