The university said Kurt Budke and Miranda Serna died in the crash Thursday afternoon in the Winona Wildlife Management Area near Perryville, about 45 miles west of Little Rock. The pilot, former Oklahoma state Sen. Olin Branstetter, and his wife Paula also died in the crash, university president Burns Hargis said at a news conference.
There were no survivors.
"This is our worst nightmare. The entire OSU family is very close, very close indeed. To lose anyone, especially these two individuals who are incredible life forces in our family, it is worse beyond words," Hargis said.
The crash is the second major tragedy for the sports program in about a decade. In January 2001, 10 men affiliated with the university's men's basketball team died in a Colorado plane crash, prompting the university to require that planes used by the school's sports team undergo safety checks before travel. It wasn't immediately clear if the same policy applied to travel by coaches or administrators.
"When something like this happens and, God forbid it happened again, we have to pull together as a family, we have to try to do that," Hargis said, as he broke down in tears.
Oklahoma State canceled its women's college basketball home games set for Saturday and Sunday. The school's second-ranked college football team plays Friday night at Iowa State.
Hargis credited Budke, 50, with elevating the team in a tough program. Serna, he said, set a good example for the players.
"Our hearts and prayers go out to the families of Kurt Budke, Miranda Serna and the other victims. Kurt was an exemplary leader and a man of character who had a profound impact on his student-athletes," Hargis said. "Miranda was an up-and-coming coach and an outstanding role model for our young ladies."
"I don't know a lot about what happened or about how it happened, but I know they are gone. They are here in our hearts," he told reporters.
OSU Director of Communications Gary Schutt said counselors are available on campus for members of the team, faculty and anyone who needs help, and that a memorial was being planned for Monday.
OSU hired Budke from Louisiana Tech seven years ago and the coach compiled a 112-83 record at the school. This year's team was 1-0 after defeating Rice on Sunday.
The National Transportation Safety Board said it was sending investigators, and that it could take nine months to determine the cause of the crash.
FAA records showed that the plane was built in 1964 and registered to Branstetter.
The plane that crashed in 2001, a Beechcraft King Air 200, had been donated by a school booster.
On Jan. 27, 2001, one of three planes carrying players and others connected to the OSU men's basketball team crashed in a field 40 miles east of Denver as the Cowboys returned from a game at Colorado. The crash occurred about 35 minutes after the plane took off in light snow.
An NTSB report cited a power loss aboard the plane and said the pilot suffered disorientation while flying the plane manually with still-available instruments.
After that crash, the university began requiring a firm to check out the condition of any plane used by a school sports team. It wasn't immediately known if that policy also applied to planes that carry only coaches or other school employees, or if the plane the women's coaches were traveling in had undergone an independent check.
Thursday night, the weather near the crash site was clear with temperatures in the upper 30s to mid-40s.