BERLIN — The German military intends to revive its controversial Euro Hawk unmanned aerial vehicle program after it was canceled in 2013 due to spiraling costs and airworthiness issues.

Sources at the German Defense Ministry of Defense confirmed that the drone, developed by Northrop Grumman, would be "taken out of the garage" in order to finish testing its integrated signal intelligence system (ISIS) from Airbus Defence & Space.

In October, German Defense Minister Ursula von der Leyen announced her intention to get the Euro Hawk drone in the air for test flights again in a move to recoup some of the €600 million (US $750 million) already invested in the project.

The German Air Force is keen to fill the gap left in its signals intelligence (SIGINT) capability since the retirement of a fleet of five Breguet Br 1150 Atlantique aircraft in 2010.

"We need this technology in order to generate a clear intelligence picture on which to base our decisions, and this is a specific area of intel that we currently don't have," said Lt.ieutenant Col.onel Gero von Fritsche, Defense Ministry spokesman.

He said that there are no plans to complete development on a Euro Hawk series. Instead, the military is eyeing options to put the drone's SIGINT payload on an alternative platform. One of the most likely options for this is the Triton MQ-4C drone, which, like the Euro Hawk, is based on the initial Global Hawk design. The Triton has also been developed by Northrop for the US Navy.

However, von Fritsche confirmed that manned aircraft, platforms, such as Airbus' ACJ319 or Bombardier's Global Express XRS or Global 5000 business jets, are also being considered. No decision has been made yet.

"There's no point in looking only at unmanned systems if we run into the problem of not being able to certify and fly the system," he said.

A spokeswoman for the joint venture, EH GmbH, released a statement saying it is "proud" to be working with its German partners.

"The German Federal Ministry of Defense awarded EH GmbH a contract modification to restart maintenance and testing on the Euro Hawk Full Scale Demonstrator on January 15, 2015," the statement said. "The award authorizes the de-preservation and maintenance assessment of the Full Scale Demonstrator aircraft in Manching, Germany. We are proud to work with our German partners and believe that a high-altitude long-endurance aircraft is the only platform able to fulfill Germany's SIGINT requirements.

Former German Defense Minister Thomas De Maiziere canceled the Euro Hawk program in May 2013 when it became apparent the plane would not get flight clearance over Europe.

This was due in part to NATO Stanag 4671, which requires lightning and icing protection on all aircraft flying over Europe. The original RQ-4 that was going to make up the program doesn't have those protections.

In addition, the Euro Hawk lacked an on board "sense and avoid system" to avoid collisions, a prerequisite to obtain flight permission in the EU.

Aaron Mehta in Washington contributed to this report.

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