After years of rumblings about problems in the Northrop Grumman RQ-4 Global Hawk, the Pentagon plans to discontinue building this long endurance unmanned surveillance aircraft due to its high cost and maintenance. According to a report in Defensenews.com, despite recently acquiring Block 30 Global Hawks, with the cost of each aircraft estimated to be around $215 million, the Air Force plans to stop building the aircraft and existing planes in the current inventory would be retired. It is unclear how many Global Hawks the Air Force has. Three Global Hawks have been deployed in support of the global war on terrorism (GWOT), serving in the Iraq and Afghanistan wars. The USAF has from time to time expressed its concerns over the Global Hawk. Maj.Gen. David Eichorn, of the U.S. Air Force Operational Test and Evaluation Centre (AFOTEC), had said in a 2011 interview that the Global Hawk Block 20/30 was “effective with significant limitations” and that it was “not suitable and partially mission capable”.