Pilot/Controller Glossary

4/3/14

PCG I−2

Regulations Part 91, prescribes standard takeoff rules

for certain civil users. At some airports, obstructions

or other factors require the establishment of

nonstandard takeoff minimums, departure proce-

dures, or both to assist pilots in avoiding obstacles

during climb to the minimum en route altitude. Those

airports are listed in FAA/DOD Instrument Approach

Procedures (IAPs) Charts under a section entitled

“IFR Takeoff Minimums and Departure Procedures.”

The FAA/DOD IAP chart legend illustrates the

symbol used to alert the pilot to nonstandard takeoff

minimums and departure procedures. When depart-

ing IFR from such airports or from any airports where

there are no departure procedures, DPs, or ATC

facilities available, pilots should advise ATC of any

departure limitations. Controllers may query a pilot

to determine acceptable departure directions, turns,

or headings after takeoff. Pilots should be familiar

with the departure procedures and must assure that

their aircraft can meet or exceed any specified climb

gradients.

IF/IAWP− Intermediate Fix/Initial Approach Way-

point. 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 IAWP.

IFWP− Intermediate Fix Waypoint

ILS−

(See INSTRUMENT LANDING SYSTEM.)

ILS CATEGORIES− 1. Category I. An ILS approach

procedure which provides for approach to a height

above touchdown of not less than 200 feet and with

runway visual range of not less than 1,800 feet.−

2. Special Authorization Category I. An ILS

approach procedure which provides for approach to

a height above touchdown of not less than 150 feet

and with runway visual range of not less than 1,400

feet, HUD to DH. 3. Category II. An ILS approach

procedure which provides for approach to a height

above touchdown of not less than 100 feet and with

runway visual range of not less than 1,200 feet (with

autoland or HUD to touchdown and noted on

authorization, RVR 1,000 feet).− 4.  Special

Authorization Category II with Reduced Lighting.

An ILS approach procedure which provides for

approach to a height above touchdown of not less

than 100 feet and with runway visual range of not less

than 1,200 feet with autoland or HUD to touchdown

and noted on authorization (no touchdown zone and

centerline lighting are required).− 5. Category III:

a.

IIIA.−An 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.−An 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.−An ILS approach procedure which

provides for approach without a decision height

minimum and without runway visual range

minimum.
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 closely spaced

independent approaches are permitted. Also used in

conjunction with an LDA PRM, or RNAV (GPS)

PRM approach to conduct Simultaneous Offset

Instrument Approach (SOIA) operations. No

Transgression Zone (NTZ) monitoring is required to

conduct these approaches. When the runway spacing

is less than 3,600 feet, the NTZ must be monitored by

a Precision Runway Monitor (PRM) or other high

update rate surveillance system.

(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) [ICAO]− A situation

wherein uncertainty exists as to the safety of an

aircraft and its occupants.

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 REFUELING−

(See AERIAL REFUELING.)