(Newser) – US fighter jets running low on fuel dropped four bombs on Australia's Great Barrier Reef last week, reports the BBC, in a training mission gone wrong. The AV-8B Harriers were supposed to drop the bombs—two of which were disabled, while two were inert—on a bombing range on a nearby island, but were forced to abort the mission and ditch payload in order to safely return to the USS Bonhomme Richard, adds CNN. The 500-lb. bombs landed in some 165 feet of water, away from the fragile coral and out of the way of passing ships. The exercise was a joint operation between American and Australian armed forces. (Read more Great Barrier Reef stories.)