The selection of the Boeing-Leonardo MH-139 ends a years-long quest to replace the 1970s-era UH-1Ns. Almost two decades after the U.S. Air Force started trying to replace the Vietnam-era helicopters that patrol missile fields and stand by to evacuate senior officials, the service announced Monday that it has placed an initial order of MH-139 helicopters with the team of Boeing and Italian defense firm Leonardo.

Today’s contract awards $375 million for the first four MH-139s, the first batch of what is slated to be a $2.38 billion, 84-aircraft program. The deal is structured as a firm fixed-price contract, meaning that the company, not the government, would be on the hook for cost overruns. Air Force officials said the program was initially estimated to cost $4.1 billion. “Strong competition drove down costs for the program, resulting in $1.7 billion in savings to the taxpayer,” Air Force Secretary Heather Wilson said in a statement.