Northrop Grumman (NYSE:NOC), one of the biggest winners in the Air Force's seismic shift toward unmanned airplanes, increased its lead even further Tuesday.

According to the company, Northrop has just been awarded an "undefinitized" contract worth $71 million, as the USAF retains the company's services to "provide engineering support for the production and final acceptance testing of ... Lot 10" Global Hawk drones. (Lot 10 refers to the sequential order number of batches of new Global Hawks bought by the Air Force.)

Northrop's tasks will include supporting "program management, engineering, and flight operations necessary to complete Lot 10 aircraft and sensor deliveries, which will include" two Block 30 Global Hawk aircraft, two more advanced Block 40 drones, and retrofits of advanced sensors upon a further three drones from previous "lots" purchased.

Northrop expects all work on this contract modification to be complete by the end of next year.

Northrop shares declined 0.2% in Tuesday trading despite the Global Hawk news, closing at $71.56.

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