WASHINGTON — The KC-46A Pegasus tanker program director is "not comfortable" saying the tanker's first flight will happen as planned in April.

Brig. Gen. Duke Richardson, program executive officer for tankers, told an audience Tuesday that he is now targeting a more general date of second quarter of this calendar year, which extends all the way to the end of June.

"What I'm trying not to do is get fixated on days," Richardson said at the CreditSuisse/McAleese conference, held annually in Washington.DC. "I feel more comfortabley saying second quarter calendar 15. I feel more comfortable with that."

The KC-46A will replace the majority of the service's current tanker fleet with 179 new planes, based on a Boeing commercial design. The contract protects the Air Force from for major cost overruns on the way to having 18 planes ready to go tankers on the ramp in 2017.

The first engineering, manufacturing, development (EMD) configuration flew in late December, while first flight of a full-up KC-46A had been scheduled for April. That now appears to be slipping.

Richardson acknowledged that there are schedule pressures driving the tests, noting that the six-month margin that had been built into the tanker EMD phase has been used up.

"I take that very seriously," he said. "I'm working pretty darn hard to pull some schedule margin back in."

Because of that tight schedule, Richardson said he wants to get the first flight up as soon as possible, regardless of whether if the tanker is in its final configuration or just one that meets the requirements for first official flight.

"As soon as we can get it up, we need to get it up," he said. "We need to do what's needed so it can fly safely, but … I'm not looking for the perfect airplane. I'm looking for a safe airplane so I can get it up and start collecting the air worthiness data."

A spokeswoman for Boeing, the prime contractor on the tanker program, said the company is "working hard every day to get ready for that first flight and have a good team in place putting forth the effort to keep it on track and moving forward... it will fly when it's ready."

It wasn't all bad news from Richardson, who said overall the program was "very healthy" and has benefitted from "incredible" requirements stability.

He also highlighted two potential foreign sales opportunities: a direct commercial sale to South Korea and a foreign military sale to Japan. Korea is expected to downselect its choice of tanker in May, while Richardson said he expects an RFP from Japan sometime in April.

Twitter: @AaronMehta