TBL 4-1-3

Other Frequency Usage Designated by FCC
Use

Frequency

Air-to-air communication
(private fixed wing aircraft).
Helicopter air-to-air communications; air
traffic control operations.
Aviation instruction, Glider, Hot Air Balloon
(not to be used for advisory service).
Assignment to flight test land and aircraft stations
(not for air-to-air communication except for
those aircraft operating in an oceanic FIR).

1This frequency is available only to itinerant stations that have a requirement to be periodically transferred to various

locations.
2Mobile station operations on these frequencies are limited to an area within 320 km (200 mi) of an associated flight test
land station.

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 continuously 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 Chart Supplement
U.S. indicates airports for which ATIS is provided.
b. ATIS information includes:
1. Airport/facility name
2. Phonetic letter code
3. Time of the latest weather sequence (UTC)
4. Weather information consisting of:
(a) Wind direction and velocity
(b) Visibility
(c) Obstructions to vision

Services Available to Pilots

4-1-9