Robert E. (Bo) Rein, the recently named head football coach at Louisiana State University, was presumed killed early today in the mysterious crash of a small airplane off the Virginia coast.

Rein, 34, and the pilot were aboard the plane on what was to have been a 57-minute hop from Shreveport, La., to Baton Rouge after a day-long recruit trip. However, a line of thunderstorms over southeast Louisiana apparently forced the pilot, Lewis Benscotter of Baton Rouge, to change his flight path, and he radioed that he was heading toward Memphis to avoid the bad weather.

That was the last voice contact with the Cessna Conquest twin-engine turboprop, although Air Force interceptors were able to fly practically wing-to-wing with the plane from Raleigh, N.C., until it plunged into the Atlantic Ocean from a height of 41,000 feet.

The Coast Guard reported no sign of life at the crash site, which is about 120 miles east of Cape Charles, Va. No wreckage, bodies or an oil slick has been spotted.

Rein "is presumed dead," said Paul Manasseh, LSU sports information director.

Rein, who had led North Carolina State University to the Atlantic Coast Conference title this past year, was signed Nov. 30 by LSU to replace Charles McClendon, who retired after 18 years as the Tigers' head coach.

Rein had signed a four-year contract at $50,000 per year. He already had hired his staff and had signed 18 of the 30 players allowed to be given grants-in-aid.

After his recruiting visit with All-State center Alvin Burns in Shreveport, Rein boarded the Cessna Thursday night for what should have been a routine flight. However, the pilot radioed Fort Worth to ask for a routing to the east because he had run into bad weather, according to Jim Santa Anna of the Federal Aviation Administration office there.

The new path and a height ceiling of 23,000 feet were approved but, Santa Anna said, radar showed that the Cessna continued to climb to 25,000 feet.

The "service ceiling" -- the level at which cabin pressurization can break down -- is 37,000 feet for the Cessna, according to one Air Force officer who declined to let his name be used. If an airplane goes above the service ceiling, hypoxia -- a form of oxygen starvation -- can set in.

The Cessna climbed as high as 41,000 feet.

If hypoxia set in, the officer said, the men could have been light-headed before going unconscious. The plane could have continued to run on automatic pilot until it ran out of fuel.

After the contact with Fort Worth, radio communication was lost, but radar continued to track the Cessna and reported that it was "dipping erratically," according to a spokesman for the Air Force Rescue Coordination Center at Scott Air Force Base, Ill.

The dipping between 25,000 feet and 41,000 feet would have been consistent with the movement of a plane flying on automatic pilot, said Sgt. Paul Munt of the rescue center. However, he said no firm conclusions will be possible until the flight recorder is recovered.

Once the plane crossed into the East Coast air defense zone and failed to answer challenges from Air Force ground tracking stations, two National Guard F-4 Phantom jet fighters took off in pursuit from Seymour Johnson Air Force Base near Goldsboro, N.C.

The Phantoms spotted the Cessna west of Raleigh. Ironically, that was the city where Rein had worked as a football coach for four years before moving to LSU.

By that time, the Cessna was at 30,000 feet and still climbing, according to Maj. Robert Walton of the Air Force rescue center at Scott Air Force Base in Illinois.

The F-4s followed the Cessna to the coast until they started to run our of fuel. Then, an F-106 from Langley Air Force Base in Hampton, Va., took up the chase and followed the plane out to sea.

The F-106 pilot, Capt. Daniel Zoerb, said he watched helplessly as the Cessna, which had been moving at speeds of 180 to 190 miles per hour, ran out of gas, made a right turn and spiraled 41,000 feet into the ocean.

"I could see both the Cessna's exterior and cabin lights," he said, "It began to go down at about 3,000 to 4,000 feet a minute. At 26,000 feet, it slowed momentarily and then accelerated its descent to 5,000 feet a minute."

Zoerb, who followed the Cessna down as close to the ocean as possible, said there was no explosion or fireball. Although Zoerb said that at first he thought he could see an oil slick, he later said he was not certain because of the changing colors of the sea water at night.

In Washington, federal officials said the Cessna Conquest 441 had been grounded twice because of control problems that could make the plane climb or dive erratically.

Rein came to LSU after a stint at North Carolina State in which his teams won two bowl games and last season's ACC championship. When he came to N.C. State as head coach at the age of 31, he became the youngest head man at a major school in the country.

A graduate of Ohio State, where he had played football under Woody Hayes, Rein also had played baseball.

After graduation, he was an assistant to Hayes for three years before becoming an assistant coach at North Carolina State, Purdue and Arkansas.