1978-09-25
Pacific Southwest Airlines
Flight PSA182
Departure
Los Angeles International Airport, Los Angeles, USA
Destination
San Diego International Airport, San Diego, USA
Causation Breakdown
Recurrence Likelihood Today
Very Low
TCAS is now mandatory on all commercial aircraft and provides automatic avoidance advisories independent of crew sight-lines. ATC radar systems have been significantly upgraded. Mode C transponders are mandatory in all Class B and C airspace.
Summary
Pacific Southwest Airlines Flight 182 collided in mid-air with a Cessna 172 training aircraft over San Diego after the crew lost visual contact with the small plane. All 135 aboard and 9 on the ground were killed. The accident remains the deadliest in California history and was the direct driving force behind the eventual mandating of TCAS on all commercial aircraft worldwide — a technology that has since prevented dozens of mid-air collisions.
Cause & Investigation
Determined cause
Mid-air collision with light aircraft
The PSA 727 collided with a Cessna 172 trainer over San Diego during approach. The 727 crew had been alerted to traffic but reported having it in sight, then lost visual contact. ATC also lost track of the Cessna on radar. The Cessna was struck from above and behind, shearing off the 727's right wing root. The jetliner entered a steep dive and crashed into the North Park neighborhood, killing all 135 aboard and 9 on the ground.
Investigation body
National Transportation Safety Board (NTSB), USA.
Timeline & Safety Improvements
Flight PSA182 disaster
Boeing 727-214 operating for Pacific Southwest Airlines. 144 fatalities, 0 survivors.
Formal investigation opened
Conducted by: National Transportation Safety Board (NTSB), USA.
Cause determined: Mid-air collision with light aircraft
The PSA 727 collided with a Cessna 172 trainer over San Diego during approach. The 727 crew had been alerted to traffic but reported having it in sight, then lost visual contact. ATC also lost track of the Cessna on radar. The Cessna was struck from above and behind, shearing off the 727's right wing root. The jetliner entered a steep dive and crashed into the North Park neighborhood, killing all 135 aboard and 9 on the ground.
Improvement implemented
The accident became the primary catalyst for mandatory TCAS (Traffic Collision Avoidance System) on commercial aircraft.
Improvement implemented
Terminal Control Area radar procedures were reviewed to improve tracking of small aircraft near busy airports.
Improvement implemented
Transponder carriage requirements for general aviation aircraft in terminal airspace were strengthened.
Improvement implemented
Coordination procedures between approach controllers and tower were revised.