Common traffic advisory frequency
（重定向自CTAF）
Common traffic advisory frequency (CTAF), is the name given to the VHF radio frequency used for air-to-air communication at US, Canadian and Australian non-towered airports.
Many towered airports close their towers overnight, keeping the airport itself open for cargo operations and other activity. Pilots use the common frequency to coordinate their arrivals and departures safely, giving position reports and acknowledging other aircraft in the airfield traffic pattern.