00637nam a22002052 4500 hsl001005501 DGPO 20170826152540.0 170106s1977 dcu r f000 0 eng d GPO GPO MvI TD 4.8/2:6510.6 TD 4.8/2:6510.6 U.S. national aviation standard for the VHF air-ground communications system. [Washington, D.C., 1977]. v. 11/11/77. CRDP Program Historic Shelflist record. Air traffic control Communication systems. United States. Federal Aviation Administration. BEV Fed Docs 264019 264019