IAF
(See INITIAL APPROACH FIX.)

IAP
(See INSTRUMENT APPROACH PROCEDURE.)

IAS. IFR TAKEOFF MINIMUMS AND DEPARTURE PROCEDURES
Title 14 Code of Federal

IAS. VFR NOT RECOMMENDED
An advisory provided by a flight service station to a pilot during a preflight or inflight weather briefing that flight under visual flight rules is not recommended. To be given when the current and/or forecast weather conditions are at or below VFR minimums. It does not abrogate the pilot’s authority to make his/her own decision.

IAWP
Initial Approach Waypoint

IFWP
Intermediate Fix Waypoint

ICAO
(See ICAO Term INTERNATIONAL CIVIL AVIATION ORGANIZATION.)

IDENT
A request for a pilot to activate the aircraft transponder identification feature. This will help the controller to confirm an aircraft identity or to identify an aircraft. (Refer to AIM.)

IDENT FEATURE
The special feature in the Air Traffic Control Radar Beacon System (ATCRBS) equipment. It is used to immediately distinguish one displayed beacon target from other beacon targets. (See IDENT.)

IF
(See INTERMEDIATE FIX.)

IF NO TRANSMISSION RECEIVED FOR (TIME)
Used by ATC in radar approaches to prefix procedures which should be followed by the pilot in event of lost communications. (See LOST COMMUNICATIONS.)

IF/IAWP
Intermediate Fix/Initial Approach Waypoint. The waypoint where the final approach course of a T approach meets the crossbar of the T. When designated (in conjunction with a TAA) this waypoint will be used as an IAWP when approaching the airport from certain directions, and as an IFWP when beginning the approach from another

IFIM
(See INTERNATIONAL FLIGHT INFORMATION MANUAL.)

IFR
(See INSTRUMENT FLIGHT RULES.)
IFR AIRCRAFT
An aircraft conducting flight in accordance with instrument flight rules.

IFR CONDITIONS
Weather conditions below the minimum for flight under visual flight rules. (See INSTRUMENT METEOROLOGICAL CONDITIONS.)

IFR DEPARTURE PROCEDURE
(See IFR TAKEOFF MINIMUMS AND DEPARTURE PROCEDURES.) (Refer to AIM.)

IFR FLIGHT
(See IFR AIRCRAFT.)

IFR LANDING MINIMUMS
(See LANDING MINIMUMS.)

IFR MILITARY TRAINING ROUTES (IR)
Routes used by the Department of Defense and associated Reserve and Air Guard units for the purpose of conducting low-altitude navigation and tactical training in both IFR and VFR weather conditions below 10,000 feet MSL at airspeeds in excess of 250 knots

IFR CLASS B
Generally, that airspace from the surface to 10,000 feet MSL surrounding the nation’s busiest airports in terms of airport operations or passenger enplanements. The configuration of each Class B airspace area is individually tailored and consists of a surface area and two or more layers (some Class B airspaces areas resemble upside-down wedding cakes), and is designed to contain all published instrument procedures once an aircraft enters the airspace. An ATC clearance is required for all aircraft to operate in the area, and all aircraft that are so cleared receive separation services within the airspace. The cloud clearance requirement for VFR operations is “clear of clouds.”

IFR/IFR
Standard IFR separation;

IFR/VFR
Traffic advisories and conflict resolution; and
II
instrument runway served by ILS and visual aids intended for operations down to 30 m (100 feet) decision height and down to an RVR of the order of 400 m. d. Precision Approach Runway, Category
III
instrument runway served by ILS to and along the surface of the runway and: 1. Intended for operations down to an RVR of the order of 200 m (no decision height being applicable) using visual aids during the final phase of landing;
IIIA.
ILS approach procedure which provides for approach without a decision height minimum and with runway visual range of not less than 700 feet. b.
IIIB.
ILS approach procedure which provides for approach without a decision height minimum and with runway visual range of not less than 150 feet. c.
IIIC.
ILS approach procedure which provides for approach without a decision height minimum and without runway visual range minimum.

ILS
(See INSTRUMENT LANDING SYSTEM.)

ILS PRM APPROACH
An instrument landing system (ILS) approach conducted to parallel runways whose extended centerlines are separated by less than 4,300 feet and at least 3,000 feet where independent closely spaced approaches are permitted. Also used in conjunction with an LDA PRM, RNAV PRM or GLS PRM approach to conduct Simultaneous Offset Instrument Approach (SOIA) operations. No Transgression Zone (NTZ) monitoring is required to conduct these approaches. ATC utilizes an enhanced display with alerting and, with certain runway spacing, a high update rate PRM surveillance sensor. Use of a secondary monitor frequency, pilot PRM training, and publication of an Attention All Users Page are also required for all PRM approaches. (Refer to AIM)

IM
(See INNER MARKER.)

IMC
(See INSTRUMENT METEOROLOGICAL CONDITIONS.)

IMMEDIATELY
Used by ATC or pilots when such action compliance is required to avoid an imminent situation. INCERFA (Uncertainty Phase)

INCREASE SPEED TO (SPEED)
(See SPEED ADJUSTMENT.)

INERTIAL NAVIGATION SYSTEM
An RNAV system which is a form of self-contained navigation. (See Area Navigation/RNAV.)

INFLIGHT WEATHER ADVISORY
(See WEATHER ADVISORY.)

INFORMATION REQUEST
A request originated by an FSS for information concerning an overdue VFR aircraft.

INITIAL APPROACH FIX
The fixes depicted on instrument approach procedure charts that identify the beginning of the initial approach segment(s). (See FIX.) (See SEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE.)

INITIAL APPROACH SEGMENT
(See SEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE.)

INITIAL APPROACH SEGMENT [ICAO]
That segment of an instrument approach procedure between the initial approach fix and the intermediate approach fix or, where applicable, the final approach fix or point.

INLAND NAVIGATION FACILITY
A navigation aid on a North American Route at which the common route and/or the noncommon route begins or ends.

INNER MARKER
A marker beacon used with an ILS (CAT II) precision approach located between the middle marker and the end of the ILS runway, transmitting a radiation pattern keyed at six dots per second and indicating to the pilot, both aurally and visually, that he/she is at the designated decision height (DH), normally 100 feet above the touchdown zone elevation, on the ILS CAT II approach. It also marks progress during a CAT III approach. (See INSTRUMENT LANDING SYSTEM.) (Refer to AIM.)

INNER MARKER BEACON
(See INNER MARKER.)

INREQ
(See INFORMATION REQUEST.)

INS
(See INERTIAL NAVIGATION SYSTEM.)

INSTRUMENT APPROACH
(See INSTRUMENT APPROACH PROCEDURE.)

INSTRUMENT APPROACH PROCEDURE [ICAO]
A series of predetermined maneuvers by reference to flight instruments with specified protection from obstacles from the initial approach fix, or where applicable, from the beginning of a defined arrival route to a point from which a landing can be completed and thereafter.

INSTRUMENT APPROACH PROCEDURES CHARTS
(See AERONAUTICAL CHART.)

INSTRUMENT DEPARTURE PROCEDURE (DP)
A preplanned instrument flight rule (IFR) departure procedure published for pilot use, in graphic or textual format, that provides obstruction clearance from the terminal area to the appropriate en route structure. There are two types of DP, Obstacle Departure Procedure (ODP), printed either textually or graphically, and, Standard Instrument Departure (SID), which is always printed graphically. (See IFR TAKEOFF MINIMUMS AND DEPARTURE PROCEDURES.) (See OBSTACLE DEPARTURE PROCEDURES.) (See STANDARD INSTRUMENT DEPARTURES.) (Refer to AIM.) INSTRUMENT DEPARTURE PROCEDURE (DP)

INSTRUMENT FLIGHT RULES
Rules governing the procedures for conducting instrument flight. Also a term used by pilots and controllers to indicate type of flight plan. (See INSTRUMENT METEOROLOGICAL CONDITIONS.) (See VISUAL FLIGHT RULES.) (See VISUAL METEOROLOGICAL CONDITIONS.) (See ICAO term INSTRUMENT FLIGHT RULES.) (Refer to AIM.)

INSTRUMENT FLIGHT RULES [ICAO]
A set of rules governing the conduct of flight under instrument meteorological conditions.

INSTRUMENT LANDING SYSTEM
A precision instrument approach system which normally consists of the following electronic components and visual aids: a. Localizer. (See LOCALIZER.) b. Glideslope. (See GLIDESLOPE.) c. Outer Marker. (See OUTER MARKER.) d. Middle Marker. (See MIDDLE MARKER.) e. Approach Lights. (See AIRPORT LIGHTING.) (Refer to 14 CFR Part 91.) (Refer to AIM.)

INSTRUMENT METEOROLOGICAL CONDITIONS
Meteorological conditions expressed in terms of visibility, distance from cloud, and ceiling less than the minima specified for visual meteorological conditions. (See INSTRUMENT FLIGHT RULES.) (See VISUAL FLIGHT RULES.) (See VISUAL METEOROLOGICAL CONDITIONS.)

INSTRUMENT RUNWAY
A runway equipped with electronic and visual navigation aids for which a precision or Nonprecision approach procedure having straight-in landing minimums has been approved. (See ICAO term INSTRUMENT RUNWAY.)

INTEGRITY
The ability of a system to provide timely warnings to users when the system should not be used for navigation.

INTERMEDIATE APPROACH SEGMENT
(See SEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE.)

INTERMEDIATE APPROACH SEGMENT [ICAO]
That segment of an instrument approach procedure between either the intermediate approach fix and the final approach fix or point, or between the end of a reversal, race track or dead reckoning track procedure and the final approach fix or point, as appropriate.

INTERMEDIATE FIX
The fix that identifies the beginning of the intermediate approach segment of an instrument approach procedure. The fix is not normally identified on the instrument approach chart as an intermediate fix (IF). (See SEGMENTS OF AN INSTRUMENT
APPROACH PROCEDURE.)

INTERMEDIATE LANDING
On the rare occasion that this option is requested, it should be approved. The departure center, however, must advise the ATCSCC so that the appropriate delay is carried over and assigned at the intermediate airport. An intermediate landing airport within the arrival center will not be accepted without coordination with and the approval of the

INTERNATIONAL AIRPORT [ICAO]
Any airport designated by the Contracting State in whose territory it is situated as an airport of entry and departure for international air traffic, where the formalities incident to customs, immigration, public health, animal and plant quarantine and similar procedures are carried out.

INTERNATIONAL CIVIL AVIATION ORGANIZATION [ICAO]
A specialized agency of the United Nations whose objective is to develop the principles and techniques of international air navigation and to foster planning and development of international civil air transport. a. Regions include: 1. African-Indian Ocean Region 2. Caribbean Region 3. European Region 4. Middle East/Asia Region 5. North American Region 6. North Atlantic Region 7. Pacific Region 8. South American Region



INTERNATIONAL FLIGHT INFORMATION MANUAL
A publication designed primarily as a pilot’s preflight planning guide for flights into foreign airspace and for flights returning to the U.S. from foreign locations.

INTERROGATOR
The ground-based surveillance radar beacon transmitter-receiver, which normally scans in synchronism with a primary radar, transmitting discrete radio signals which repetitiously request all transponders on the mode being used to reply. The replies received are mixed with the primary radar returns and displayed on the same plan position indicator (radar scope). Also, applied to the airborne element of the TACAN/DME system. (See TRANSPONDER.) (Refer to AIM.)

INTERSECTION
a. A point defined by any combination of courses, radials, or bearings of two or more navigational aids. b. Used to describe the point where two runways, a runway and a taxiway, or two taxiways cross or meet.

INTERSECTION DEPARTURE
A departure from any runway intersection except the end of the runway. (See INTERSECTION.)

INTERSECTION TAKEOFF
(See INTERSECTION DEPARTURE.)