What happened
On the evening of the accident, Airwest flight 706, an DC-9, was operating a scheduled multi-stop service from Los Angeles to Seattle. After departing Los Angeles at 18:02, the crew reported descending through 12,000 feet and received clearance to proceed toward Daggett.
Simultaneously, a US Marine Corps McDonnell F-4B Phantom, registration 15145</strong>58, was flying at a low altitude from NAAS Fallon toward MCAS El Toro. This military aircraft was experiencing several mechanical issues, specifically an oxygen system leak and a non-functioning transponder. As visibility worsened northwest of Palmdale, the crew increased their altitude to 15,500 feet. During this phase, the pilot performed a 360-degree aileron roll. Following the maneuver, the aircraft leveled off at approximately 420 knots true airspeed.
Approximately 80 seconds after the roll was completed, the F-4B Phantom collided with the Airwest DC-9 at an altitude of 15,150 feet. The impact caused the military jet to enter a violent lateral tumble. While the Radar Intercept Officer successfully ejected and landed without injury, the second crewmember of the F-4B was killed in the accident. There were no reported fatalities among the passengers or crew of the Airwest flight.
Findings
Investigations into the collision identified that both flight crews failed to detect and avoid one another, though it was noted that their ability to identify the other aircraft was severely limited. The high closure rate between the two aircraft made avoidance difficult. Additional contributing factors included the mixing of IFR and VFR traffic in an airspace where air traffic control-provided separation was not fully effective. Furthermore, the crew of 151458 did not request radar advisory services despite the lack of a working transponder.