all clear n a signal (usually a siren) that danger is over n permission to proceed because obstacles have been removed
News & Articles all clear All clear after evacuations at airport The all clear has been given after a portion of the McNamara Terminal at Detroit's Metro Airport was evacuated due to a suspicious situation. June 18, 2013 - WXYZ-TV Detroit All Clear Given After Bomb Threat Called In To Will Rogers Airport The all clear has been given at Will Rogers Airport after a bomb threat was called in around 5:30 p.m. Saturday. June 16, 2013 - KWTV News9