The US Air Force has discovered another “category one” deficiency on its already-troubled KC-46 aerial refueling and military transport aircraft.
Kevin Stamey, the service’s program executive officer for mobility aircraft, said in a recent conference in Ohio that vibrations from the plane’s fuel pump were damaging its bleed air ducts.
The Pegasus uses bleed air – or compressed air extracted from its engines – to help regulate cabin pressure and prevent the formation of ice on its wings.
According to Stamey, KC-46 manufacturer Boeing has worked quickly to repair the damaged ducts and is now testing a workaround for the issue.
A longer-term design fix is also likely, he noted.
“We potentially have a path to downgrade that (issue) as we work toward a permanent fix,” he said. “The mitigation is designed to minimize the damage caused by the vibration.”
Seven ‘Category One’ Deficiencies
The US Air Force describes “category one” deficiencies as any issue that could cause loss of an aircraft, severe injuries, or deaths.
They could prevent a plane from performing well enough to accomplish its primary or secondary missions.
In August 2023, an air force official disclosed that the Pegasus still has six category one deficiencies to address to operate safely.
Among them is the issue with the tanker’s remote vision system, which prevents boom operators from clearly seeing the receptacle, potentially damaging the receiving plane.
Other serious problems involve the aircraft’s auxiliary power unit and fuel system.
Program leader Col. David Hall said the air force and Boeing are now in varying stages of resolving the category one deficiencies, with three of those getting closer to a resolution.
‘A Logical Choice’
Regarded as the world’s most advanced aerial refueling aircraft, the KC-46 Pegasus is expected to modernize the US military’s aging tanker fleet.
It is powered by two high-bypass turbofans, allowing the aircraft to carry up to 200,000 pounds (90,718 kilograms) of fuel.
It can also be configured for transport missions, accommodating more than 58 passengers or 65,000 pounds (29,545 kilograms) of cargo.
According to an opinion article written by retired Air Force Colonel Al Baker for The Defense Post, the KC-46 is the “most logical choice” for US tanker recapitalization as it has already met or exceeded strict certification requirements.