The US Air Force (USAF) plans to move $57 million in FY2020 funds from the Boeing KC-46A Pegasus in-flight refuelling tanker programme to support the cost of flying and maintaining its fleet of older KC-135 Stratotankers longer than it expected.

Air Mobility Command is planning to operate some legacy KC-135 tankers longer than planned because of delivery delays and deficiencies with the Boeing KC-46, according to a report by the Government Accountability Office (GAO). The service accepted the first KC-46 in January 2019, but the aircraft have three critical deficiencies related to the refuelling subsystems. The company was on contract to deliver 18 aircraft with three fully functional aerial refuelling subsystems in 2017, but won’t deliver on that promise until June 2020 – nearly three years behind schedule.

Boeing KC-46A Pegasus at factory

KC-46A at Boeing facility


Air Mobility Command officials told the GAO that its decision to retain some legacy KC-135 aircraft would be reviewed annually. If the 1950s-era aircraft are retained more funding would be shifted from the KC-46 programme to support the older tankers.

Boeing plans to deliver 36 KC-46 tankers to the service in 2019 despite two stoppages earlier in the year when foreign object debris was found inside multiple aircraft. Those aircraft will later receive retrofits to fix issues.

Programme officials estimate it will take three to four years to develop fixes for the deficiencies and a few more years to retrofit up to 106 aircraft in the field, says the GAO. The USAF and Boeing will incur costs to fix the deficiencies, with the service’s portion estimated to be more than $300 million. The USAF is withholding 20% payment on each aircraft until Boeing fixes the deficiencies and other non-compliance issues.

The USAF plans to limit some refuelling operations until the KC-46 tankers become fully functional, says the GAO.