Dead air is an unintended period of silence that interrupts a broadcast during which no audio or video program material is transmitted.
Dead air occurs in radio broadcasting when no audio program is transmitted for an extended period of time, usually more than a few seconds. In television broadcasting, the term denotes the absence of both audio and video program material. Technically, a carrier wave may still be transmitting; in radio, the result is silence, and in television, the result is a silent black image.
Although television directors may use the command "fade to black" or "to black" to indicate a momentary transition to a completely black image, the term "dead air" is most often used in cases where program material comes to an unexpected halt, either through operator error or technical malfunction. Among professional broadcasters, dead air is considered one of the worst things that can occur. Moreover, dead air could affect advertising revenue if it affects the airplay of paid commercials.
The term "dead air" does not refer to a broadcast transmitter that is intentionally shut down, i.e. "closed", "signed off" or "off the air", by a control operator; such a broadcast transmitter is said to have gone "dark".
In the US, dead air, if prolonged and occurring without permission, is an actionable offense that can result in fines from the FCC.
Broadcast stations can use programmable devices known as "silence sensors", "off air alarms" or "silence monitors" that will sound an alarm and alert personnel if dead air persists more than a few seconds.
On September 11, 1987, Dan Rather walked off the set of the CBS Evening News when a late running U.S. Open tennis match threatened to delay the start of his news broadcast. The match then ended sooner than expected but Rather was gone. The network broadcast six minutes of dead air before Rather was found and returned to the studio. CBS affiliates criticized Rather for the incident.
One significant case of dead air occurred during Super Bowl LII in 2018, when the NBC television broadcast experienced 26 seconds of dead air during a commercial break. The network blamed "a brief equipment failure", and stated that no commercial advertising was lost. Prior to Super Bowl XLV, Green Bay radio station WCHK-FM announced that it would intentionally go to dead air during the game, since the hometown Packers were playing in the game.
When BBC Radio 2 host Chris Evans did not arrive for work on time resulting in Vanessa Feltz filling in for 30 minutes until Evans took the microphone. The Guardian characterized it as a promotional stunt that forced Feltz "to fill the dead air with jokes".
French public broadcasting network Radio France automatically broadcasts a musical loop (called emergency program) in the event of dead air lasting more than a few seconds. This program is broadcast in the event of unscheduled interruption (due to a fire in the building or technical issues), as well as during programmed blackouts caused by strikes of technicians, journalists, and producers. During such blackouts (which can last for weeks ), a pre-recorded message will inform listeners that no service is available due to industrial action.
On March 7, 2021, CBS went to dead air for at least 12-15 seconds while airing an interview special.