AIM
4/3/14
4−1−7
Services Available to Pilots
TBL 4
−1−3
Other Frequency Usage Designated by FCC
Use
Frequency
Air-to-air communication
(private fixed wing aircraft).
122.750
Air-to-air communications
(general aviation helicopters).
123.025
Aviation instruction, Glider, Hot Air
Balloon (not to be used for
advisory service)
.
123.300
123.500
4
−
1
−
12. Use of UNICOM for ATC Purposes
UNICOM service may be used for ATC purposes,
only under the following circumstances:
a.
Revision to proposed departure time.
b.
Takeoff, arrival, or flight plan cancellation
time.
c.
ATC clearance, provided arrangements are
made between the ATC facility and the UNICOM
licensee to handle such messages.
4
−
1
−
13. Automatic Terminal Information
Service (ATIS)
a.
ATIS is the continuous broadcast of recorded
noncontrol information in selected high activity
terminal areas. Its purpose is to improve controller
effectiveness and to relieve frequency congestion by
automating the repetitive transmission of essential
but routine information. The information is continu-
ously broadcast over a discrete VHF radio frequency
or the voice portion of a local NAVAID. Arrival ATIS
transmissions on a discrete VHF radio frequency are
engineered according to the individual facility
requirements, which would normally be a protected
service volume of 20 NM to 60 NM from the ATIS
site and a maximum altitude of 25,000 feet AGL. In
the case of a departure ATIS, the protected service
volume cannot exceed 5 NM and 100 feet AGL. At
most locations, ATIS signals may be received on the
surface of the airport, but local conditions may limit
the maximum ATIS reception distance and/or
altitude. Pilots are urged to cooperate in the ATIS
program as it relieves frequency congestion on
approach control, ground control, and local control
frequencies. The A/FD indicates airports for which
ATIS is provided.
b.
ATIS information includes the time of the latest
weather sequence, ceiling, visibility, obstructions to
visibility, temperature, dew point (if available), wind
direction (magnetic), and velocity, altimeter, other
pertinent remarks, instrument approach and runway
in use. The ceiling/sky condition, visibility, and
obstructions to vision may be omitted from the ATIS
broadcast if the ceiling is above 5,000 feet and the
visibility is more than 5 miles. The departure runway
will only be given if different from the landing
runway except at locations having a separate ATIS for
departure. The broadcast may include the appropriate
frequency and instructions for VFR arrivals to make
initial contact with approach control. Pilots of aircraft
arriving or departing the terminal area can receive the
continuous ATIS broadcast at times when cockpit
duties are least pressing and listen to as many repeats
as desired. ATIS broadcast must be updated upon the
receipt of any official hourly and special weather. A
new recording will also be made when there is a
change in other pertinent data such as runway change,
instrument approach in use, etc.
EXAMPLE
−
Dulles International information Sierra. 1300 zulu
weather. Measured ceiling three thousand overcast.
Visibility three, smoke. Temperature six eight. Wind
three five zero at eight. Altimeter two niner niner two. ILS
runway one right approach in use. Landing runway one
right and left. Departure runway three zero. Armel
VORTAC out of service. Advise you have Sierra.
c.
Pilots should listen to ATIS broadcasts
whenever ATIS is in operation.
d.
Pilots should notify controllers on initial
contact that they have received the ATIS broadcast by
repeating the alphabetical code word appended to the
broadcast.
EXAMPLE
−
“Information Sierra received.”
e.
When a pilot acknowledges receipt of the ATIS
broadcast, controllers may omit those items con-
tained in the broadcast if they are current. Rapidly
changing conditions will be issued by ATC and the
ATIS will contain words as follows:
EXAMPLE
−
“Latest ceiling/visibility/altimeter/wind/(other condi-
tions) will be issued by approach control/tower.”
NOTE
−
The absence of a sky condition or ceiling and/or visibility
on ATIS indicates a sky condition or ceiling of 5,000 feet or
above and visibility of 5 miles or more. A remark may be