Aeronautical Acronyms beginning with I
IAF
initial approach fix
IAP
instrument approach procedure
IAS
indicated air speed
ICA
initial climb area
ICAO
International Civil Aviation Organization
IF
intermediate fix
IFR
instrument flight rules
ILS
instrument landing system
IMC
instrument meteorological conditions
INS
inertial navigation system
IOC
initial operational capability
IPV
instrument procedure with vertical guidance (this term has been renamed APV) IRU Inertial Reference Unit