Boeing has completed the first flight of the US Air Force's (USAF) KC-46 Pegasus aircraft at Paine Field in Everett, Washington.
Designated as EMD-3, the 767-2C is the fourth and final flight test aircraft to join the KC-46 Pegasus fleet.
The aircraft, without the aerial refuelling system installed, will be used to conduct environmental control system testing, including hot day / cold day testing and smoke penetration testing.
The test validated the engine, flight controls and environmental systems of the aircraft during the one hour and 40 minute maiden flight.
Test pilots took the 767-2C to a maximum altitude of 39,000ft prior to landing at Boeing field, south of Seattle.
Boeing has built four test aircraft to design and develop the USAF's next-generation tanker, under a contract awarded in 2011.
Of the four test aircraft, two are configured as 767-2Cs and two as KC-46 tankers. Eventually, both 767-2Cs will become KC-46 tankers.
EMD-1, the first 767-2C test aircraft, completed more than 315 flight test hours since its first flight in December 2014.
The programme's first KC-46 tanker EMD-2 made its maiden flight in September 2015 and has completed more than 240 flight test hours, including refuelling F-16, F/A-18 and AV-8B aircraft. It also has been refuelled by a KC-10 tanker.
EMD-4, the second tanker, first flew on 2 March this year and has completed 25 flight hours.
Boeing plans to build 179 KC-46 aircraft for the USAF.
Image: The 767-2C taking off. Photo: courtesy of Tim Stake, Boeing photo.