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Pilot/Controller Glossary

3/29/18

PCG I−1

I

I SAY AGAIN− The message will be repeated.
IAF−

(See INITIAL APPROACH FIX.)

IAP−

(See INSTRUMENT APPROACH

PROCEDURE.)

IAWP− Initial Approach Waypoint
ICAO−

(See ICAO Term INTERNATIONAL CIVIL

AVIATION ORGANIZATION.)

ICAO 3LD−

(See ICAO Term ICAO Three−Letter Designator)

ICAO Three−Letter Designator (3LD)− An ICAO

3LD is an exclusive designator that, when used

together with a flight number, becomes the aircraft

call sign and provides distinct aircraft identification

to air traffic control (ATC). ICAO approves 3LDs to

enhance the safety and security of the air traffic

system. An ICAO 3LD may be assigned to a

company, agency, or organization and is used instead

of the aircraft registration number for ATC

operational and security purposes. An ICAO 3LD is

also used for aircraft identification in the flight plan

and associated messages and can be used for

domestic and international flights. A telephony

associated with an ICAO 3LD is used for radio

communication.
ICING− The accumulation of airframe ice.
Types of icing are:

a. Rime Ice− Rough, milky, opaque ice formed by

the instantaneous freezing of small supercooled

water droplets.

b. Clear Ice− A glossy, clear, or translucent ice

formed by the relatively slow freezing or large

supercooled water droplets.

c. Mixed− A mixture of clear ice and rime ice.

Intensity of icing:

a. Trace− Ice becomes perceptible. Rate of

accumulation is slightly greater than the rate of

sublimation. Deicing/anti-icing equipment is not

utilized unless encountered for an extended period of

time (over 1 hour).

b. Light− The rate of accumulation may create a

problem if flight is prolonged in this environment

(over 1 hour). Occasional use of deicing/anti-icing

equipment removes/prevents accumulation. It does

not present a problem if the deicing/anti-icing

equipment is used.

c. Moderate− The rate of accumulation is such that

even short encounters become potentially hazardous

and use of deicing/anti-icing equipment or flight

diversion is necessary.

d. Severe− The rate of ice accumulation is such

that ice protection systems fail to remove the

accumulation of ice, or ice accumulates in locations

not normally prone to icing, such as areas aft of

protected surfaces and any other areas identified by

the manufacturer.  Immediate exit from the condition

is necessary.

Note:

Severe icing is aircraft dependent, as are the other

categories of icing intensity.  Severe icing may

occur at any ice accumulation rate.

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.)

IDENTIFICATION [ICAO]− The situation which

exists when the position indication of a particular

aircraft is seen on a situation display and positively

identified.
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.)

IFR−

(See INSTRUMENT FLIGHT RULES.)

2/28/19

Pilot/Controller Glossary