All planes in the United States that carry more than 30 passengers must be equipped by the end of 1991 with a device to warn of impending collisions, the government ordered Thursday.

The landmark Federal Aviation Administration rule requires airlines for the first time to install the devices, which automatically alert pilots to make specific maneuvers to avert a collision if ground controllers allow them to get too close, The New York Times said Friday.Transportation Secretary Jim Burnley called the rule issued Thursday "one of the most significant safety initiatives in recent years."