On September 25, 1978, Pacific Southwest Airlines Flight 182 was preparing to land in San Diego. The Boeing 727 was cleared to descend — but another small plane was flying nearby. Air traffic control believed the pilots could see and avoid the smaller aircraft. They couldn’t. Seconds later, the two planes collided mid-air above the city. The jet crashed into a neighborhood, destroying homes on the ground. 144 people lost their lives, including people in the houses below. The investigation reveal

What Happened To PSA After The Merger With USAir? - Air Traffic Insider