A “Broken Arrow” is defined as an unexpected event involving nuclear weapons that results in the accidental launching, firing, detonating, theft or loss of the weapon.
A Titan-II intercontinental ballistic missile (ICBM) was launched from Florida into the South Pacific without giving notice to the Moorestown Radar warning site. Only the projection of the course of the missile led to the conclusion it was not to be labelled a threat.
Further materials:
https://futureoflife.org/background/nuclear-close-calls-a-timeline/
