The 32-member Lake Braddock Secondary School orchestra will be going to Bermuda after all. The orchestras at Chantilly Secondary School and Mount Vernon High also will be going.

Fairfax County School Superintendent S. John Davis, reversing an earlier decision, yesterday agreed to allow the three school orchestras to participate in the spring music festival in Bermuda.

Jacqueline Benson, an associate superintendent, said Davis "reluctantly" decided to permit the students to attend the festival, scheduled for April 26-30, because they already have raised the bulk of the needed money for the trip.

"We're delighted that they're going," said County Supervisor Marie Travesky (R-Springfield), who had pressed the Lake Braddock students' request with school officials.

The orchestra members at Lake Braddock had done various jobs, including forming string quartets to perform at private parties, to raise $8,000 of the $11,000 needed for the trip when they got the word from school officials that the trip had been disapproved. Benson said similar requests from the other two schools also were disapproved.

Benson said the superin tendent initially objected that there were similar festivals within the country that the orchestras could attend. She said the school system also lacks liability insurance for trips abroad.

She said the school orchestras will have to pay for the liability insurance coverage. "I'm confident we will come up with it (liability insurance coverage)," Travesky said.