The Marine Corps has halted work on Boeing’s [BA] unmanned cargo helicopter, the A160T Hummingbird, because of “technical issues” with the system designed to fly higher and deliver greater payloads, Naval Air Systems Command (NAVAIR) and the company confirmed recently.

Boeing was notified of the 60-day stop-work order on Dec. 15. The work suspension will allow the Navy and Marine Corps to evaluate the A-160T and determine the best course of action, NAVAIR spokeswoman Jamie Cosgrove said. She and Boeing would not specify problems underlying the technical issues.

“They are still working towards maturing the system,” Cosgrove said.

Boeing spokeswoman Elaine Brabant said the company would remain in discussions with NAVAIR and the Marine Corps and emphasized the stop-work order was not a contract termination.

“We will continue to progress this revolutionary prototype program into a capability to address the emerging needs of the warfighter,” Brabant said, noting that it was a developing system. She said the stoppage will not impact the A160T’s development under a separate contract with the Army for intelligence, reconnaissance and surveillance missions.

The A160T is competing against the Lockheed Martin [LMT] and Kaman Aerospace [KAMN] K-MAX. K-MAX completed Quick Reaction Assessment testing earlier this year and two of the systems were deployed to Afghanistan in November. K-MAX has since begun carrying cargo to Marines, Lockheed Martin spokesman Jeff Brown said recently.

NAVAIR had previously said the A160T was scheduled for a Quick Reaction Assessment sometime in the spring of 2012. It was not clear how the stop-work order would affect that timeframe.

The Navy awarded dueling development contracts to Lockheed Martin and Boeing in December 2010 to create an unmanned airlift capability in response to an urgent requirements request by Marines in Afghanistan. The unmanned, autonomous flying helicopters are intended to reduce risks, such as ambushes or improvised explosive devices (IEDs), associated with moving supplies on the ground.

Boeing inherited Hummingbird when it acquired Frontier Systems in 2004.

The president of Boeing Military Aircraft, Chris Chadwick, said in an interview last month that the Hummingbird would be ready for deployment but would like to see the A160T moving along faster.

“I wouldn’t say there’s any one technology area that is causing us issues,” he said. “It’s just moving from prototype to the development to the production phase and that’s where we’re at right now.”