12/2/21
Pilot/Controller Glossary
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 of large
supercooled water droplets.
c.
Mixed
−
A mixture of clear ice and rime ice.
Intensity of icing:
a.
Trace
−
Ice becomes noticeable. The rate of
accumulation is slightly greater than the rate of
sublimation. A representative accretion rate for
reference purposes is less than ¼ inch (6 mm) per
hour on the outer wing. The pilot should consider
exiting the icing conditions before they become
worse.
b.
Light
−
The rate of ice accumulation requires
occasional cycling of manual deicing systems to
minimize ice accretions on the airframe. A
representative accretion rate for reference purposes is
¼ inch to 1 inch (0.6 to 2.5 cm) per hour on the
unprotected part of the outer wing. The pilot should
consider exiting the icing condition.
c.
Moderate
−
The rate of ice accumulation
requires frequent cycling of manual deicing systems
to minimize ice accretions on the airframe. A
representative accretion rate for reference purposes is
1 to 3 inches (2.5 to 7.5 cm) per hour on the
unprotected part of the outer wing. The pilot should
consider exiting the icing condition as soon as
possible.
d.
Severe
−
The rate of ice accumulation is such
that ice protection systems fail to remove the
accumulation of ice and ice accumulates in locations
not normally prone to icing, such as areas aft of
protected surfaces and any other areas identified by
the manufacturer. A representative accretion rate for
reference purposes is more than 3 inches (7.5 cm) per
hour on the unprotected part of the outer wing. By
regulation, immediate exit is required.
Note:
Severe icing is aircraft dependent, as are the other
categories of icing intensity. Severe icing may
occur at any ice accumulation rate when the icing
rate or ice accumulations exceed the tolerance of
the aircraft.
IDAC
−
(See INTEGRATED DEPARTURE/ARRIVAL
CAPABILITY.)
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.)
PCG I
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