WASHINGTON — The U.S. Air Force’s super secret B-21 bomber program is gliding toward a major development milestone known as the critical design review, which is set to wrap up by the end of 2018, the director of the Air Force’s Rapid Capabilities Office said Monday.

“We’ve been through the preliminary design review, so we’re on a path to go into a more critical design and move on with the production of not only the test aircraft, but if I have my way, make sure that we get the development done properly leading up to an on-time start of production,” Randall Walden said at a Mitchell Institute for Aerospace Studies event. Walden’s office, the RCO, is in charge of developing the B-21 and ensuring the program’s success.

“From my perspective, this is about producing 100 bombers, not about just getting through development,” he added. “Development is a phase that leads into the fielding of this critical need. So my focus is getting the production started, but I can’t do that until we understand what the design looks like.”