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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