1991 Los Angeles runway collision

On the evening of Friday, 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). As Flight 1493 was on final approach, the local controller was distracted, though air traffic was not heavy at LAX, 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.

Upon landing, the 737 collided with the smaller turboprop Metroliner, which was crushed beneath the larger USAir jet as it continued down the runway, caught fire, and veered into an airport fire station. Rescue workers arrived in minutes and began to evacuate the 737, but because of the intense fire, three of the 737's six exits were unusable, including both front exits; front passengers could only use one of the two overwing exits, causing a bottleneck. All 12 people aboard the smaller plane were killed, along with an eventual total of 23 of the 89 occupants of the 737, with 20 on the 737 caused by asphyxiation in the fire. One passenger from the 737 died from injuries 31 days later.

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. The crash led directly to the NTSB's recommendation of using different runways for takeoffs and landings at LAX.

Flight

Skywest 5569 was cleared by ATC Wascher in the LAX tower to taxi to Runway 24L, moving from gate 32 to the runway via taxiways Kilo, 48, Tango, and 45.

Immediately prior to SkyWest 5569 reaching runway 24L, a Wings West aircraft had landed on 24R and was awaiting permission to cross 24L and taxi to the terminal. The local controller attempted to contact the Wings West aircraft, but the crew had changed frequencies and did not answer, distracting Wascher as she attempted to reestablish communications. Shortly after 6 PM local time, as USAir 1493 was on final approach to LAX, the SkyWest Metroliner was cleared by the local controller to taxi into position and hold on Runway 24L at the intersection of taxiway 45, some 2200 ft up from the runway threshold. After four attempts by the local controller, the Wings West aircraft finally responded to the tower and apologized for switching frequencies. Wascher then cleared the USAir flight to land on 24L, even though the SkyWest Metroliner was still holding in takeoff position on the runway:

With this activity ongoing, another Wings West aircraft, a Metroliner similar to SkyWest 5569, called the tower reporting they were ready for takeoff. Wascher queried this aircraft about their position, and they told her they were holding on a taxiway short of 24L. The flight progress strip for this flight had not yet been given to Wascher by controller Vandiver (another distraction), and Wascher mistakenly thought this Metroliner was SkyWest 5569, and thus that the runway was clear of aircraft. The first officer of the USAir flight recalled hearing this conversation, but did not remember anyone being cleared to hold on the runway. Meanwhile, Wascher was busy handling other flights:

The USAir plane touched down near the runway threshold. Just as the nose was being lowered, the first officer noticed SkyWest 5569 on the runway and applied maximum braking, but it was too late. The following was recorded on the CVR:

The USAir plane slammed into the Metroliner, crushing it beneath its fuselage. The 737 proceeded to skid down the runway, then veered off the left side and came to rest on the far side of the taxiway against a closed fire station building, where it eventually caught fire. Large debris from the Metroliner – including its tail, wings, and right engine – were found on the runway and between the runway and the abandoned fire station.