The costs of the Air Force’s RQ-4 Global Hawk remotely piloted aircraft program grew significantly through the end of 2010, the Defense Department informed Congress last week. The aircraft’s program acquisition unit cost increased 14 percent compared to its current cost baseline and its average procurement unit cost rose 22.8 percent, according to DOD’s newly issued selected acquisition reports for 2010’s final quarter. The cost spikes have triggered a “critical” breach of the Nunn-McCurdy cost-monitoring thresholds. As a result, the Pentagon must review the program and certify to Congress by June 14 that its continuation is vital to national security. Primarily driving the cost spike was the change in the RQ-4 mix to a larger percentage of more expensive Block 30 airframes and less Block 40s, said DOD. Pentagon officials anticipated the breach last year and have already begun making some changes, said DOD.