Four F-35A Lightning IIs were officially delivered to the US Air Force Warfare Center at Nellis AFB, Nevada, on 19 March 2013. The four aircraft are assigned to the 422nd Test and Evaluation Squadron of the 53rd Test and Evaluation Group. Official welcoming ceremonies at Nellis marked the handover of the jets to the Air Force. The delivery of the first four operational-coded 5th generation F-35A CTOL fighters to Nellis marks the beginning of operational testing and evaluation at the base. These four aircraft increases the number of CTOL aircraft delivered to the Air Force to twenty-four and brings the total number of F-35s delivered to the DOD to fifty-eight.