List of Abbreviations

Blind Landings: Low-Visibility Operations in American Aviation, 1918–1958

A-1	a U.S. Army Air Corps landing aid, also known as the “Hegenberger system”
AAF	Army Air Forces
ALPA	Air Line Pilots Association
AN/MPN-1	a World War II–era GCA system
AOPA	Aircraft Owners and Pilots Association
ARINC	Aeronautical Radio, Inc.
ARL	Aircraft Radio Laboratory (Wright Field, Dayton, Ohio)
ATA	Air Transport Association
BABS	blind approach beacon system
CAA	Civil Aeronautics Authority (until 1940); Civil Aeronautics Administration (after 1940)
FCC	Federal Communications Commission
FIDO	a thermal fog dispersion device
GCA	ground-controlled approach
IATCB	Interagency Air Traffic Control Board
ILS	instrument landing system
ITRM/ITD	International Telephone and Radio Manufacture; International Telephone Development Company (same company as the Federal Telephone Development Corporation)
NAS	National Academy of Sciences
NBS	U.S. National Bureau of Standards
PGP	pulsed glide path
PPI	planned position indicator
RAE	Royal Aircraft Establishment
RTCA	Radio Technical Commission on Aeronautics
SBA	standard beam approach system
SCS-51	U.S. Army version of the instrument landing system
UAL	United Air Lines
UHF	ultra-high frequency (after 1944; frequencies between 3 MHz and 30 MHz)
USSTAF	U.S. Strategic and Tactical Air Forces
VHF	very high frequency (after 1944; frequencies between 30 MHz and 3 GHz)
YB	a U.S. Navy version of ILS