Incident Overview
At 11:10 on the day of the accident, Wings West Airlines Flight 628, a commuter flight operating between Los Angeles and San Francisco with scheduled stops at Santa Maria and San Luis Obispo, departed the gate at San Luis Obispo. The weather was essentially clear with visibility of 15 miles. At 11:16, after taking off from runway 29, Flight 628 contacted Los Angeles ARTCC, reporting that it was climbing through 2,700 feet 'IFR to San Francisco.' At 11:17:23, the Los Angeles ARTCC radar controller cleared Flight 628 to the San Francisco airport, as filed, to climb and maintain 7,000 feet.
Collision
At 11:17:38, the aircraft collided head-on with Rockwell Commander N112SM at 3,400 feet. N112SM was a single-engine aircraft that had departed Paso Robles Airport on a training flight with two pilots on board. It was flying in visual meteorological conditions and under VFR in the vicinity of the San Luis Obispo Airport just before the collision.
Probable Cause
According to the official investigation, the probable cause was the failure of the pilots of both aircraft to follow the recommended communications and traffic advisory practices for uncontrolled airports contained in the Airman’s Information Manual to alert each other to their presence and to enhance the controller’s ability to provide timely traffic advisories. Underlying the accident were the physiological limitations of human vision and reaction time. Also underlying the accident was the short time available to the controller to detect and appraise radar data and to issue a safety advisory. Contributing to the accident was the Wings West Airlines policy which required its pilots to tune one radio to the company frequency at all times.