AVON PARK, FLA.--Frank A. Corbett, 84, of Avon Park, FL, and formerly of Plaistow, N.H., died Nov. 13, in Sebring, Fla. Born in Eastport, Maine,, son of the late John D. and Vera W. (Chaffey) Corbett, he attended local schools. Corbett served in the United States Navy during the Korean Conflict a