A B-1 Lancer ejection seat malfunction that drove the Air Force to call for a stand-down of its conventional bomber will be fixed quickly, Defense Secretary Jim Mattis said Monday.

“I’m not concerned about it. Whatever it is, it will be fixed very quickly,” Mattis said of the issue, which came to light in May. In that incident a B-1 crew experiencing a potentially catastrophic engine fire was unable to eject from the jet, due to an ejection seat malfunction for one of the four crew members. The crew remained on board and was able to successfully land the bomber at Midland International Air and Space Port.

“There are times where we find a problem with some aspect of an airplane so we’ll shut’em down, we’ll check it and they come back up very quickly,” Mattis said. “We’ll just have to watch and see how this goes.”

Separately, an F-15 crashed in Okinawa Sunday, leading to a freeze in training sorties there. On Monday Military Times reported that there was a second B-1 emergency landing just days before the Air Force declared the stand -down.

Mattis’ comments come as each of the services top officers for aviation safety will be testifying on Capitol Hill Wednesday on their plans to address a sharp rise in aviation accidents over the last five years. An in-depth investigation by Military Times found in April that mishaps involving the nation’s bomber, fighter, tanker, helicopter and tiltrotor warplanes jumped almost 40 percent since 2013.

Mattis said the issue has the Pentagon’s full attention.

“What we’re doing on readiness — there’s trailing indicators I would call them,” Mattis said. “In other words, if you fail to do things five years ago, three years ago, one year ago, you don’t reverse all those things with the money that Congress has given us.”

Over the weekend he worked through a large binder of readiness issues the services had prepared and are reporting to him. Those issues will be the subject of a separate Wednesday meeting at the Pentagon led by Deputy Secretary Patrick Shanahan.

“This is probably ‘The Thing’” in terms of priorities for the department, Mattis said. Using his hands, Mattis described the book of readiness challenges the services have compiled as about three inches thick, “with each of the services going through their major programs – where’s there’s been readiness problems, an d what we’re doing on each one as we apply the money, or the time, or the troops.”

Mattis met with Pentagon reporters on the record for about 30 minutes Monday and took questions about operations around the world and particularly on North Korea, where President Donald Trump and North Korean leader Kim Jong Un where scheduled to meet.