<s>
A	O
UNICOM	B-Algorithm
(	O
universal	B-Algorithm
communications	I-Algorithm
)	O
station	O
is	O
an	O
air-ground	O
communication	O
facility	O
operated	O
by	O
a	O
non-air	O
traffic	O
control	O
private	O
agency	O
to	O
provide	O
advisory	O
service	O
at	O
uncontrolled	O
aerodromes	O
and	O
airports	O
and	O
to	O
provide	O
various	O
non-flight	O
services	O
,	O
such	O
as	O
requesting	O
a	O
taxi	O
,	O
even	O
at	O
towered	O
airports	O
.	O
</s>
<s>
UNICOM	B-Algorithm
is	O
employed	O
at	O
airports	O
with	O
a	O
low	O
volume	O
of	O
general	O
aviation	O
traffic	O
and	O
where	O
no	O
control	O
tower	O
is	O
active	O
.	O
</s>
<s>
UNICOM	B-Algorithm
stations	O
typically	O
use	O
a	O
single	O
communications	O
frequency	O
.	O
</s>
<s>
Some	O
airfields	O
always	O
offer	O
UNICOM	B-Algorithm
service	O
while	O
others	O
revert	O
to	O
UNICOM	B-Algorithm
procedures	O
only	O
during	O
hours	O
when	O
the	O
control	O
tower	O
is	O
closed	O
.	O
</s>
<s>
During	O
these	O
times	O
,	O
pilots	O
self-announce	O
their	O
position	O
and/or	O
intentions	O
over	O
the	O
CTAF	B-Algorithm
frequency	O
,	O
which	O
is	O
often	O
the	O
same	O
as	O
the	O
UNICOM	B-Algorithm
frequency	O
.	O
</s>
<s>
When	O
a	O
part-time	O
UNICOM	B-Algorithm
station	O
is	O
located	O
on	O
the	O
same	O
airport	O
as	O
a	O
part-time	O
control	O
tower	O
,	O
the	O
same	O
frequency	O
will	O
be	O
used	O
by	O
both	O
ground	O
stations	O
to	O
avoid	O
confusion	O
.	O
</s>
<s>
Many	O
UNICOM	B-Algorithm
stations	O
are	O
operated	O
by	O
a	O
fixed-base	O
operator	O
(	O
FBO	O
)	O
,	O
and	O
it	O
may	O
be	O
possible	O
to	O
request	O
services	O
such	O
as	O
fuel	O
trucks	O
,	O
taxi	O
service	O
from	O
the	O
airport	O
,	O
outgoing	O
phone	O
calls	O
,	O
and	O
others	O
.	O
</s>
<s>
In	O
the	O
United	O
States	O
,	O
radio	O
frequencies	O
made	O
available	O
by	O
the	O
Federal	O
Communications	O
Commission	O
for	O
use	O
as	O
UNICOM	B-Algorithm
are	O
:	O
</s>
<s>
Airports	O
with	O
an	O
Air	B-Application
Traffic	I-Application
Control	I-Application
tower	O
or	O
FSS	O
(	O
Alaska	O
only	O
)	O
on	O
the	O
airport	O
.	O
</s>
<s>
Airports	O
without	O
an	O
Air	B-Application
Traffic	I-Application
Control	I-Application
tower	O
or	O
FSS	O
on	O
the	O
airport	O
.	O
</s>
<s>
In	O
Canada	O
,	O
the	O
radio	O
frequencies	O
assigned	O
for	O
UNICOM	B-Algorithm
are	O
:	O
</s>
