Students at MIT yesterday mourned the loss of two fellow undergraduates who were killed Sunday when a skydiver collided with the small airplane in which they were returning to campus.

Jonas R. Klein and Christina Park, both 18, were flying back from upstate New York to Boston's Logan International Airport when the crash occurred. The plane's pilot--Jonas' father Elliot Klein, 49--and the fourth passenger, family friend Jean Kimball, 45, were also killed in the crash.

Around 2:30 p.m. Sunday, skydiver Alfred Peters, 51, jumped from a Cessna aircraft and accelerated to about 120 miles per hour when he struck the rear of Klein's single-engine Piper Cherokee PA28. Peters, who had not yet opened his parachute, apparently hit the plane with his ankle, sending it into a fatal tailspin.

"He struck the vertical stabilizer in the rear of the aircraft causing it to go into a vertical tailspin from which it never recovered," Mary Culver, a spokesperson for the Federal Aviation Administration, said in a telephone interview yesterday.

While all four passengers aboard the aircraft were killed, the skydiver managed to open his parachute and sustained only a fractured leg and a broken ankle, Culver said.

Culver said Peters is an "accomplished skydiver" and that he had been cleared for his jump by air traffic controllers at Bradley International Airport in Windsor Locks, Conn.

The skydiver, who had logged 37 previous jumps, told authorities he leaped from the single-engine Cessna at about 8,000 feet above the airport. Within moments, he saw the Piper heading straight at him before he struck its tail section, according to Jeff Guzzetti, and inspector for the National Transportation Safety Board.

"As he was floating to earth...he saw this airplane spiraling to the ground." Guzzetti told the Associated Press.

Klein and Park were friends at MIT, where they had several common friends and shared an interest in techno-music, an MIT spokesperson said yesterday. Friends said the pair had traveled to Poughkeepsie, N.Y., for a techno-music concert, the spokesperson said.

Klein, who grew up in Monterey, Mass., and attended Northfield Mt. Herman High School, was a first-year student and a pledge at the Tau Epsilon Phi fraternity, said Charles H. Ball, an assistant director of the MIT news office. Klein would have been initiated into the fraternity in two weeks, Ball said.

"The brothers and friends of Tau Epsilon Phi mourn the loss of our brother Jonas. He was a hacker in every sense of the word, and we are going to miss him greatly. We send our love and condolences to his family, friends and everyone who knew him," Tau Epsilon Phi brother Adam C. Ganderson '97 said in a prepared statement read yesterday by the fraternity's chancellor.

Park, a native of Auburn, Washington, was a sophomore biology major who lived in the Senior House dorm on campus, Ball said, She attended Thomas Jefferson High School and was an oboe player for the Seattle Youth Symphony Orchestra.

Senior House Master John Hammond did not return a call to his office yesterday. Ball said Hammond, an MIT dean on call and a representative from MIT's medical center, met with students at Senior House Monday night to discuss the tragedy.

"It was almost like something in a movie. It wasn't real," said John Stergakis, of West Hartford, Conn., who was waiting to take his first-ever jump at the airport later that afternoon.

"We would call it a freak," said Jerry Rouillard, director of the U.S. Parachute Association in Alexandria, Va.