Boeing has completed the fuel system ground tests of the US Air Force KC-46 engineering and manufacturing design (EMD) programme at Paine Field, Washington.

During the test, a Boeing 767-2C tanker, called EMD-1, flew its first airworthiness flight installed with an aerial refuelling boom and wing air refuelling pods, Flightglobal reported.

According to Boeing KC-46 spokesman Chick Ramey, the latest test will support US Federal Aviation Administration type certification of the 767-2C.

Ramey was quoted as saying: "[The June 2 flight] really concludes the initial part of airworthiness testing, so now EMD-1 will go into planned ground testing and will do some FAA certification off the 767-2C fuel provisions.

"The latest test will support US Federal Aviation Administration type certification of the 767-2C."

"It will enter the next phase of airworthiness testing following this ground testing phase."

Boeing is planning to test four engineering and manufacturing development aircraft, such as two 767-2Cs and two KC-46As, this year. Boeing manufactures these four aircraft under a contract signed in 2011.

The first full-up KC-46A test aircraft, EMD-2, is expected to carry out its first flight in this summer. It is predicted that the company is will deliver the first 18 of 179 KC-46 aircraft to the air force by 2017.

Earlier this year, Boeing conducted a successful test flight of 767-2C freighter aircraft, in which the aircraft flew from Paine Field, Washington and landed at the Boeing field in Seattle after a successful flight for three hours and 32 minutes.