The Senate voted without dissent yesterday to call for an independent investigation of the climate that allowed a string of rape and sexual assaults to take place at the Air Force Academy in Colorado.

The amendment to a war spending bill directs the secretary of defense to appoint a seven-member panel similar to one that investigated a Naval Academy cheating scandal in 1993. If approved by the House, the panel would begin meeting by May 1 and submit a report within 90 days.

The vote followed assertions by several senators that Air Force officials have failed to get to the root of the sexual misconduct and have been unwilling to hold senior officers accountable.

"Enough is enough. It's time to take action," said the sponsor of the amendment, Sen. Wayne Allard (R-Colo.), according to the Associated Press. "Clearly, given the history involved and the lack of attention paid in the past, an external review is necessary."

Air Force Secretary James G. Roche and Chief of Staff Gen. John P. Jumper announced last week that they were replacing four of the academy's top officers, including Lt. Gen. John D. Dallager, superintendent of the academy, and Brig. Gen. S. Taco Gilbert III, commandant of cadets.

But Roche simultaneously absolved those commanders of blame, saying the scandal resulted from a longstanding climate that discouraged female cadets from reporting rapes and that predated the arrival of the academy's current leaders.

"The secretary of the Air Force has proven to our satisfaction that he cannot and will not address this situation, this crisis at the Air Force Academy, in a mature and efficient manner," said Sen. John McCain (R-Ariz.), a co-sponsor of the amendment.

Several investigations of the sexual misconduct are underway by the Air Force, the Defense Department and Colorado prosecutors. The Air Force has said it is looking into 20 rapes and 36 sexual assaults reported since 1993 by female cadets, many of whom were ostracized by classmates and punished by superiors for filing the reports.

Allard said 42 women have contacted his office to complain about the handling of their cases, including 20 who said they were raped or assaulted within the past two years. About 16 percent of the 4,200 cadets are women.

Allard's amendment calls for the special panel to "determine responsibility and accountability for the establishment or maintenance of an atmosphere . . . that was conducive to sexual misconduct."

The panel's seven members should "have knowledge or expertise in matters relating to sexual assault, rape and the United States military academies," it says.

Staff writer Helen Dewar contributed to this report.