On the evening of February 1, 1991, USAir Flight 1493, a Boeing 737-300, collided with SkyWest Airlines Flight 5569, a Fairchild Swearingen Metroliner turboprop aircraft, upon landing at Los Angeles International Airport (LAX). Though air traffic was not heavy at LAX, as Flight 1493 was on final approach, the local controller was distracted by a series of abnormalities, including a misplaced flight progress strip and an aircraft that had inadvertently switched off the tower frequency. The SkyWest flight was told to taxi into takeoff position, while the USAir flight was landing on the same runway.

On the landing, the 737 collided with the twin-engined turboprop plane, and the USAir flight continued down the runway with the turboprop crushed beneath it, exited the runway, and caught fire. All 12 people aboard the smaller plane were killed, as well as an eventual total of 23 of the 89 occupants of the Boeing 737. Rescue workers were on the scene of the fire within minutes and began the evacuation of the plane. Because of the intense fire, three of the 737's six exits could not be used. Neither of the front exits was usable, which caused the front passengers to use the overwing exits. However, only one of the overwing exits was usable, which caused a backlog to form. Most of those who died aboard the 737 succumbed to asphyxiation in the post-crash fire.

The National Transportation Safety Board (NTSB) found that the probable cause of the accident was the procedures in use at the LAX control tower, which provided inadequate redundancy, leading to a loss of situational awareness by the local controller, and inadequate oversight by the Federal Aviation Administration (FAA) for failing to supervise the control tower managers.^: vi, 76 The crash led directly to the NTSB's recommendation of using different runways for takeoffs and landings at LAX.