The driver of the truck that hit a Texas school bus last fall, sending it into a water-filled pit and killing 21 students, should have been able to stop despite faulty brakes, the National Transportation Safety Board said yesterday.

"The truck driver's inattention resulted in his failure to stop his truck," the board's report said in blaming driver Ruben Perez.

Forty-nine of the 60 other students were injured in the accident near Alton last Sept. 21. It was the nation's worst school bus accident since 1976.

Perez, who has been charged with 21 counts of manslaughter in the accident, has said the brakes failed.

Investigators said Perez told them he started to brake about 300 feet before the intersection, noticed the brakes were faulty, then tried to downshift to avoid the accident. The board said he should have kept his foot on the brakes.

Investigators found the truck's brakes were operating at about two-thirds strength, which should been enough to stop the truck if Perez had begun applying them 300 feet before the intersection.

The Texas collision was the worst U.S. school bus accident since May 1976, when 29 were killed in a bus that plunged from a freeway ramp near Martinez, Calif.

"While there were deficiencies in the truck, the performance of the truck driver was the greater deficiency," said board chairman James Kolstad.

Perez watched the proceedings impassively. "He didn't do anything wrong. His brakes failed," said Perez's attorney, Bob Binder.