Broken Arrow (military)

Broken Arrow is a call (or request) for all available combat aircraft to attack enemy positions, even those close to the position of US troops. The reason for calling in that order, is because a US position is being overrun and can no longer be defended.
Broken Arrow is a "code phrase (see code), that a [military unit on the] ground ... is facing imminent (or very soon) destruction from enemy attack and all available air forces within range are to provide air support immediately"; That is what Wiktionary.org says.
In movies and books.
In movies, the phrase has been used in "We Were Soldiers" (2002). Its movie star is Mel Gibson. 
Part of the plot of the movie is that, at the point of being overrun by the enemy, the miliary officer (played by Mel Gibson), orders his forward air controller, to call in the air strike, by saying "Broken Arrow, Broken Arrow".