The US Navy is awarding Sikorsky a $435 million contract modification to build four more CH-53K prototype helicopters for operational evaluation purposes.

Instead of awarding a separate contract for the four system demonstration test articles, the Naval Air Systems Command has decided to add the machines to an existing $3.5 billion system development and demonstration contract that was awarded in April 2006.

CH-53K - Sikorsky 

 Sikorsky

The original contract obliged Sikorsky to build five developmental test aircraft and two ground static test airframes. The four additional aircraft are going to be used strictly for mission testing, Sikorsky says.

The first aircraft is expected to be delivered within 39 months and all four aircraft are scheduled for delivery by the end of March 2017 when the US Marine Corps hopes to start its operation evaluations. Those grueling trials call for the CH-53K to haul 12,247kg (27,000lb) over a distance of 110nm (204km/h)-meaning the new K-model will have three times the external payload capacity as the old E-model helicopter.

The four additional prototypes are not production aircraft, Sikorsky emphasises. Low rate initial production will start later, however, the extra machines do count against the total CH-53K programme of record consisting of 200 helicopters, meaning there will be a total of 196 production aircraft.

Source: Flight International