i/o Input/output
IAC International Aerobatics Club
IADS Integrated air defence system
IAP International airport
IAS Indicated airspeed
IATA International Air Transport Association
IC Intercom
ICAO International Civil Aviation Organization
ICBM Inter-continental ballistic missile
ICNIA Integrated Communications, Navigation and Identification Avionics (USAF/USN)
ID Identification
IF Intermediate frequency
IFALPA International Federation of Air Line Pilots Associations
IFE In-flight entertainment
IFF Identify friend or foe
IFR Instrument flight rules
also:   In-flight refueling
IGE In ground effect; refers to helicopter hovering performance close to horizontal surface
IIR Imaging infra-red
IIRS Instrument inertial reference set
ILS Instrument landing system
IMC Instrument meteorological conditions
IMN Indicated Mach number
Imp gal Imperial gallon (= 1.201 US gallon; = 4.546 litres)
IMS Information management system
also:   Integrated management system
INAS Integrated navigation/attack system
Inc Incorporated
incidence Angle at which wing is set to fore/aft axis of aircraft
INEWS Integrated Electronic Warfare System (USAF/USN)
INF Intermediate range nuclear forces
ins Inches (= 2.54 cm)
INS Inertial navigation system; measures all accelerations on aircraft; calculates present position from known starting position using the integration of accelerations&time
INSTR Instrument
integral construction Construction machined from 1 part instead of assembled from seperate parts
integral tank A (fuel) tank formed by sealing off part of the aircraft structure
interdiction Attack on tactical targets deep inside enemy territory
INTL International
IOC Initial operational capability
IOR Immediate operational requirement
IP Instructor pilot
also:   Intermediate pressure
IR Infra-red
IRAN Inspection and repair as necessary (US)
IRCM Infra-red countermeasures
IRCCM Infra-red counter countermeasures
IRLS Infra-red line scan
IRS Inertial reference system
IRST Infra-red search and track
IRU Inertial reference unit
IRWR Infra-red warning receiver
ISA International standard atmosphere
ISAR Inverted synthetic aperture radar
ISD In service date
ISO International Standardisation Organisation
ITP Intent to purchase
also:   Instruction to proceed
ITT Invitation to tender
IVS Interactive voice system
IWS Integrated weapon system
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