TY - BOOK ED - United States. TI - Certification of normal category rotorcraft PY - 1991///] CY - [Washington, D.C. KW - Rotors (Helicopters) KW - Standards KW - United States N1 - Advisory circular; Sept. 12, 1991; Shipping list no. : 91-0744-P; CRDP Program Historic Shelflist record ER -