IFR  Instrument Flight Rules
IGES  Standardized Graphics Exchange File
IGV  Inlet Guide Vane
ILM  Independent Landing Monitor
ILS  Instrument Landing System. The system provides lat-
eral,along-course and vertical guidance to aircraft attempting a landing.
IMA  Integrated Modular Avionics
IMC Instrument Meteorological Conditions IMPATT Impact Avalanche and Transmit Time. This type of Diode diode,when mounted in an appropriate cavity, pro
duces microwave oscillations and amplification. IMTEG ICAO ILS/MLS Transition Group Europe IND Indicator INU Inertial Navigation Unit IAS Indicated Airspeed is the speed indicated by a differ-
ential pressure airspeed indicator which measures the
actual pressure differential in the pitot-static head. It
is the actual instrument indication for a given flight
condition.
Indicated  The altitude above mean sea level (uncorrected for
Altitude  temperature).
INMARSAT  International Maritime Satellite Organization
I/O  Input/Output. Refers to bi-directional data ports.
INPH  Interphone
INS  Inertial Navigation System. A self-contained,dead-reckoning system that senses the acceleration along the three axes of the aircraft and calculates the dis-tance traveled from a reference point. Accuracy of the system decreases with respect to time.
INST  Instrument
Intruder  An altitude reporting aircraft that is being considered as a potential threat and that is being processed by the threat detection logic (TCAS).
IOC  Initial Operational Capability