SdntPilot From United States of America, joined Jul 2001, 41 posts, RR: 0 Reply 1, posted (12 years 4 months 4 weeks 1 day 9 hours ago) and read 4591 times:
A "Unicom" or aeronautical advisory is an aid to a pilot who is flying into a smaller airports with out a tower. Pilots use this to get surface wind. traffic and other information that they need, but it doesnt give clearances for take off and landings and things like that.
It also lets other airplanes in the airport area no about trafic and your planes location and what your doing. You cant just fly around the airport with orther traffic coming at you. You have to let other planes no were you are so they can keep a safe distence.
If a plane was on the holding position for rwy 32 and he hears a plane on UNICOM say "CESSNA ONE FOUR EIGHT ON FINAL, RWY THREE TWO" the plane holding knows not to go because there is a plane about to land.
Hope this helped you, and if I said anything wrong hopefully someone else will correct it.
Western727 From United States of America, joined Jan 2007, 643 posts, RR: 4 Reply 2, posted (12 years 4 months 4 weeks 3 hours ago) and read 4574 times:
SdntPilot was close. What he was describing is known as "CTAF" or the Common Traffic Advisory Frequency. Unicom is a service that's usually provided by an FBO on the field. The purpose for Unicom is to give airport advisories (active runway, wind direction/speed, barometric pressure, etc.), radio checks, and for ordering fuel. At uncontrolled fields with a Unicom, the CTAF and Unicom frequencies are the same. The only difference that a pilot announcing his position calls to "Traffic" and the pilot calling Unicom addresses it to unicom. Examples (I use my home field of PVU):
"Provo Traffic, Cessna 106ES turning a left final, touch and go, Provo."
"Provo Unicom, Cessna 106ES, we are inbound for landing, can we get some gas?"
If the airport is unattended, or there is no Unicom, the CTAF is 122.9 and called "Multicom." Usually, if there is a Unicom, CTAF and Unicom will be 122.8. There are some exceptions to that. If there is an FSS on the field, Unicom will be 122.8, and CTAF will be 123.6. If you are flying at an airport with a tower, but the tower has closed for the evening, then CTAF will be the tower frequency, and Unicom will be as noted by the aeronautical chart, flight guide, etc - but still usually 122.8.
Anyway, that's how I understand it. Hope that helps. Let me know if you have any questions.
Murph From United States of America, joined Jul 2001, 37 posts, RR: 0 Reply 4, posted (12 years 4 months 3 weeks 5 days 7 hours ago) and read 4566 times:
At most un controlled airports, the weather advisories are given by a system called ATIS (Automatic Terminal Information System) it is simply a constantly updated recording of the winds, clouds, pressures and other pertinant information for pilots
Western727 From United States of America, joined Jan 2007, 643 posts, RR: 4 Reply 5, posted (12 years 4 months 3 weeks 5 days 6 hours ago) and read 4565 times:
Actually, some uncontrolled fields will have what is called "AWOS" or Automated Weather Observation Service.
ATIS gives weather information, as well as active runway, approach, and gives you a code (alpha, bravo, charlie, etc.) to verify that you have the current information when you talk to the ground controller or clearance delivery. ATIS is only used at *controlled* airports.
AWOS only gives weather information. It does not designate an active runway, and there is no code assigned to the broadcast to give to any controller. And not all uncontrolled fields have AWOS, only the more active ones. And, many of the fields that have AWOS also have a unicom.