00893nam a22002772 4500 hsl001005363 DGPO 20170826152539.0 170105s1971 dcu r f000 0 eng d GPO GPO MvI TD 4.8/2:6100.1/2 TD 4.8/2:6100.1/2 Maintenance of NAS enroute stage a air traffic control system. [Washington, D.C., 1971]. xxxvi, 790 p. : ill. [Handbook]. Dec. 6, 1968, and Changes 1-4, [1969-1971]. [Reprinted Oct. 4, 1971]. Cover title. 4to. [Reprint to include Changes. Issued with perforations]. CRDP Program Historic Shelflist record. Official use. Not available. Air traffic control. United States. Federal Aviation Administration. BEV Fed Docs 263974 263974