msoultan

I'm kinda confused on the definition of MULTICOM, UNICOM, AND CTAF. I understand that CTAF is the common traffic advisory frequency, and that is what you use at an untowered airport or when the tower is not in service.

If I remember correctly, the definition of MULTICOM refers to it being an air-to-air frequency for pilots to self-announce. So would the LA Basin traffic frequency (123.025) be considered a MULTICOM frequency?

And then I've read that UNICOM is a frequency for an advisory facility on an airport, towered and untowered. What would I use this frequency for? If I wanted to get gas, or needed to park the heli somewhere, would I call up this frequency?

thanks!
Mike

HSLD

Checkout chapter 4.1.9 in the AIM to make sure you know when and how to use them, but......



CTAF
COMMON TRAFFIC ADVISORY FREQUENCY (CTAF) - A designated frequency for the purpose of carrying out
airport advisory practices while operating to or from an airport that does not have a control tower or an airport where
the control tower Is not operational.

Self announce

The CTAF is normally a UNICOM, MULTICOM, flight service station (FSS) frequency, or a tower frequency.

CTAF will be identified in appropriate aeronautical publications.

UNICOM
UNICOM stations may provide pilots, upon request, with weather information, wind direction, the recommended
runway, or other necessary information.

If the UNICOM frequency is designated as the CTAF, it will be identified in appropriate aeronautical publications.

FSS (Flight Service Station)
An FSS physically located on an airport may provide airport advisory service (AAS) at an airport that does not have a
control tower or where a tower is operated on a part-time basis and the tower is not in operation.

The CTAFs for FSSs which provide this service are published in appropriate aeronautical publications.

MULTICOM
A mobile service, not open to public correspondence use, used for essential communications in the conduct of
activities performed by or directed from private aircraft.

NoyGonnaDoIt

Practically speaking, as indicated above, CTAF is a generic term that refers to the way we communicate with a non-towered airport. It's most often a Unicomm frequency (where some local services are provided) at a public-use airport that is always non-towered and the Tower frequency at a towered airport when the tower is closed. Multicomm frequencies tend to be used at smaller private airports.

Many airports used to have an FSS on the field and the use of their advisory services at those airports were often used. Even when there were more of them available on-field, I only come across one in more than 20 years of flying and, with the consolidation of FSS, I haven't seen any that were used for local operations, with their primary function being weather and flight plan services being all I've seen in recent years.

The AFD is your source for what is being used at any particular airport.