The Air Force has combed through 54 cases of alleged rape or sexual assault at the Air Force Academy that have been investigated over the past decade and identified about a dozen that it intends to refer to other Defense Department authorities for further review, the service's civilian leader said yesterday.

Testifying before a Senate panel about the burgeoning sexual misconduct scandal, Air Force Secretary James G. Roche acknowledged that many other cases may have occurred but were never reported. He promised changes in how the academy has managed sexual complaints so that victims will feel freer to come forward.

"Whatever we see, whatever the number is -- 25, 50 -- there are probably a hundred more that we do not see," Roche told the Senate Armed Services Committee.

In the past month, a sudden surge in complaints by former and current cadets, alleging they were sexually assaulted at the academy and then faced indifference or even retaliation after reporting the attacks, has embarrassed Air Force leaders and threatens to become the latest in a series of sexual misconduct debacles that have shaken the U.S. military over the past decade.

Sen. Wayne Allard (R-Colo.), a committee member and one of several in Congress who have pressed the Pentagon for a more aggressive inquiry, said "a total system breakdown" had made the situation at the Air Force Academy graver than the 1991 Tailhook scandal in which more than 80 women complained they were groped or assaulted by drunken pilots at a convention. That episode cost the careers of the Navy secretary and several admirals, who were accused of mishandling it.

In the case of the Air Force cadets, Allard said, "the entire support and legal system at the academy appears to have failed. We really do need to instill confidence in the system so victims know when they report rape, they know the rape itself will not jeopardize their career."

Mindful of Tailhook's lessons, Roche and other Air Force senior officials have pledged a thorough and swift inquiry. A team of Air Force investigators was dispatched to the academy last month.

So far, Air Force authorities have resisted calls from some in Congress for the removal of the academy's commanders.

"We believe this regrettable situation has resulted from a climate at the academy that has evolved over time," Roche's spokesman, Lt. Col. Chester Curtis, said yesterday. "We will not make a scapegoat of anyone . . . but will ensure justice is served on all levels."

But Roche vowed changes at least in the academy's management processes by June, when a new class of freshmen cadets is scheduled to arrive at the school in Colorado Springs, Colo. "We're learning enough to realize that change must occur -- change in the climate, change in how we manage" the academy, the secretary said.

The scandal stems from reports last month on Denver's KMGH-TV and in the Denver newspaper Westword. They related the stories of several female cadets who said they were disciplined or "hounded out" of the academy after reporting sexual assaults by male cadets.

Since then, additional complaints have flowed into congressional offices. A spokesman for Allard said the senator had received 25 as of yesterday. Several women who have reported attacks have said that academy officials sought to undermine their credibility by seizing on other violations that occurred before the reported assaults, such as drinking or inappropriate fraternization.

Roche appeared before the Senate panel with the secretaries of the Navy and the Army, and the hearing covered a broad range of issues. But when Allard's time came to ask questions, he bored in on the academy scandal, asking for a report on the Air Force's investigation and future plans.

"Many of the victims that have approached my office have refused to talk to your investigative team because they fear reprisals and do not want to jeopardize their careers," Allard said. "Are you willing to grant confidentiality to victims that might be willing to come forward?"

Roche said confidentiality would be granted whenever possible, but he noted the difficulty of doing so in instances in which the victim's testimony is critical to a criminal investigation.

The secretary testified that Air Force investigators had spent 10 days at the academy and met with six current or former cadets who said they had been sexually assaulted. The investigators plan to return next week for more meetings, including some with counselors at a crisis center that has received 28 reports of cadet rape over the past 15 years.

In an interview after the hearing, Allard said the 54 cases reviewed by the Air Force so far involved instances in which cadets were alleged to have been either victims or perpetrators of sexual assaults. Not all the allegations had been substantiated in these cases. But he said the dozen that had been singled out were instances in which either "the woman believes she didn't get due process" or "there was something else about the case" that warrants another look.

Roche said the dozen cases would be referred to the Pentagon's inspector general, Joseph E. Schmitz, who other defense officials disclosed yesterday has begun his own inquiry into the handling of sexual assault allegations at all the service academies.

In addition to these cases previously probed by Air Force criminal investigators, Roche said two new cases had emerged involving women who have come forward in the past two weeks.

In the past 10 years, the Air Force secretary said, only two cadets had been court-martialed for rape. One was acquitted, the other pleaded guilty and was sentenced to seven months in jail. In other cases, administrative action was taken because of insufficient evidence to prosecute, Roche said.

Secretary James G. Roche seeks review by inspector general.