The U.S. Air Force and Boeing may have agreed on an October 2018 delivery date for the first KC-46A aerial refueling tanker, but the service is still resolving deficiencies and testing software fixes on the program.

Lt. Gen. Arnold Bunch, the Air Force’s top military acquisition official, says that issues could come up in testing, but he is hoping to even speed up delivery if possible. “We believe [the schedule] is aggressive but achievable.”

The agreement on a delivery date represents the next step in a saga to replace the service’s Eisenhower-era KC-135 tankers that has lasted close to two decades.

Just getting to this agreement has been typical of this program – more difficult than anyone thought possible for what might have been a simple retrofit – adding a refueling capability to a long-produced commercial aircraft.

The U.S. government started looking for new tankers shortly after the Sept. 11, 2001, terrorist attacks on the Pentagon and the World Trade Center in New York City. But it was not until 2011 that Boeing landed the eventual contract award for US$3.5 billion for 18 tankers.