Investigation Summary
Golden West Flight 261 was operating a scheduled VFR flight from Ontario to LAX. At 16:04 PST, the crew contacted LAX arrival radar and was cleared for a Terminal Control Area (TCA) arrival. The controller advised the crew of a police helicopter 5.5 miles ahead, which the crew acknowledged. Meanwhile, a Cessna 150 on a local training flight from Long Beach was heading north through the same area. The Cessna was not equipped with a transponder and was not in radio contact with LAX controllers, as it was operating outside the TCA boundaries. At 16:07 PST, the two aircraft collided at a 90 degree angle. The Cessna's firewall and instrument panel became embedded in the Twin Otter's fuselage. The wreckage fell into a residential area of Whittier, with the Twin Otter's fuselage landing in a middle school yard where a basketball game was in progress. Despite the debris falling on homes and public spaces, there were no injuries on the ground.
Final Conclusions
The National Transportation Safety Board determined the probable cause was the failure of both flightcrews to see the other aircraft in time to initiate evasive action. Contributing factors included the position of the sun (9 degrees above the horizon directly in the eyes of the Golden West pilots), the closure angle of the aircraft, and the Twin Otter crew's preoccupation with visually locating other radar-reported traffic (the police helicopter) directly in front of them.
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Golden West Airlines GW261 — de Havilland Canada DHC-6 Twin Otter 200 · N6383
CessnAir Aviation N11421 — Cessna 150H · N11421
Crew Experience
Captain
First Officer
Systems & Failure Modes
See and Avoid
The primary method of collision avoidance for VFR traffic, which failed due to environmental factors and cockpit workload.
Terminal Control Area (TCA)
Designated airspace (now Class B) where specific entry requirements and altitudes were mandated to separate large commercial traffic from smaller VFR aircraft.
ARTS III
The automated radar terminal service used by controllers, which could not track the Cessna because it lacked a transponder.
Interesting Facts
- 01The collision occurred while the sun was just 9 degrees above the western horizon, creating significant glare for the Twin Otter pilots.
- 02The Cessna 150 was not equipped with a transponder, making it invisible to the ARTS III radar system used by the controller.
- 03The Twin Otter was descending at 300 feet per minute at 146 knots, while the Cessna was flying at 94 knots.
- 04The closing speed between the two aircraft was calculated at 174 knots.
- 05The Twin Otter's fuselage fell into the schoolyard of Katherine Edwards Middle School.
Safety Actions & Advisories
Pilot Vigilance Education
The NTSB recommended educational programs to make pilots more aware that most mid-air collisions occur in clear weather near airports during daylight.
Instructor Training
Recommended more stringent examination of pilot applicants, particularly flight instructors, regarding external cockpit vigilance.