The delayed delivery of Boeing’s [BA] KC-46A Pegasus refueling tankers from December to spring 2018 is due to difficulties obtaining FAA certifications, not three unresolved tests related to boom glitches and high frequency radio issues with the aircraft, according to Air Force officials. 

During a media conference Friday, Air Force officials denied the moths-long delay was related to three open deficiency reports (DR) discovered after developmental testing in May. The aircraft will undergo further evaluation beginning in October.

A KC-46 refuels an A-10 during testing. Photo: Air Force.
A KC-46 refuels an A-10 during testing. Photo: Air Force.

“Boeing has been working very steadily towards getting FAA certification that’s required, both an amended-type certification and supplemental-type certification,” an Air Force Official told reporter during a phone call Friday. “The delays have been because that’s taking more time than they had originally estimated to garner those certifications. The KC-46 during developmental testing has done aerial refueling with C-17’s, A-10’s and F-16’s. So these issues have been on those three platforms.”

There are currently three outstanding DRs related to the KC-46A involving issues with high frequency radios during refueling and glitches with the aircraft’s boom making contact with fueling receptacles.

The Air Force requires high frequency radios to not transmit during aerial refueling and first identified the issue in 2016 after discovering potential interference with flight controls. With regards to the KC-46A, the report remains open because the Air Force has not collected sufficient data to confirm that switched-off radios remain off for the entire re-fueling process.

The glitch, which occurs when the KC-46 made unintended contact with the receiving aircraft’s boom receptacle, was discovered in May. Refueling testing is set to resume in October,  and officials will decide whether to close the deficiency report if and when a cause is determined.

“As a result after the testing was completed, the team went back and looked at some data and that was when we understood that there was an issue,” the official said. “We have aerial refueling procedures that require that if the boom contacts the receiver aircraft the boom operator must notify the pilot. They must make them aware that the boom contacted outside the receptacle. Any discussions of potential fixes is premature at this point. We need to collect that data, analyze it, then devise a path forward.”

Ground testing also revealed un-commanded boom extension occurrences, which generated a third deficiency report. The Air Force is analyzing the problem to determine the root cause. 

“This test was meant to show that when you turn off the fuel quickly what happens under that pressure scenario,” the official said. “In this instance, the boom pushed forward and disconnected into the stand. Initially there was some concern, but after looking at the data from the test we believe this is not going to be an issue. Initially there was some concern, but after looking at the data from the test we believe this is not going to be an issue.”

Data collection for the boom extension deficiency is scheduled for October and November, but the Air Force does not know when a final decision would be made to close the case.