The US Navy has flown the second Northrop Grumman MQ-4C Triton unmanned aircraft system (UAS), a maritime-focused derivative of the high-altitude, long-endurance RQ-4 Global Hawk.

The second aircraft enters the test campaign 17 months after first flight of the original prototype. The first aircraft in September completed a cross-country flight from Northrop’s UAS factory in San Diego to Naval Air Station Patuxent River, Maryland.

The second aircraft will now be prepared to complete the same cross-country journey later this month.

A third test aircraft is being prepared to complete a first flight in a few weeks. The navy originally planned to fund the third aircraft, but lost the money in budget cuts. Northrop then decided to self-fund production of the third prototype.

Data gathered by all three aircraft will be used by the navy to make a decision on whether to launch production in Fiscal 2017.

The MQ-4C is based on the RQ-4C but includes a strengthened structure and wing de-icing equipment. It also carries a maritime surveillance payload, which includes a Northrop-built active radar and a receiver tuned to interrogate transponders carried on all commercial vessels.

The navy awarded Northrop the $13.5 billion contract to develop and build five test aircraft and 65 production aircraft.

The aircraft will serve as an adjunct to the Boeing P-8A Poseidon maritime patrol and anti-submarine warfare aircraft. The MQ-4C is designed to maintain continuous surveillance orbits over maritime areas from five bases spread globally, from Guam to Diego Garcia to Sicily and both the US east and west coasts.