What happened
On January 31, a Douglas DC-7B, registration N8210H, departed from the Santa Monica Airport in California. The aircraft was being operated by Douglas Aircraft employees to perform functional flight checks of its components following production. The flight crew consisted of four members: the pilot, copilot, flight engineer, and radio operator. The mission was conducted under visual flight rules with a planned duration of approximately two hours and fifteen minutes.
Simultally, a Northrop-operated F-89J, registration 52-1870, departed from Palmdale Airport as part of a series of radar system checks for the United States Air Force. This aircraft was accompanied by a second F-89J. The crew of the F-89J performed a climbing maneuver to 25,000 feet to execute a predetermined flight pattern designed to test airborne radar equipment.
At approximately 11:18, the Douglas crew transmitted an emergency message indicating they had been involved in a midair collision with a jet and that their aircraft was uncontrollable. The radio operator reported the aircraft was spinning into a valley. The collision caused the DC-7B to crash in a populated area. The accident resulted in four fatalities among the flight crew of the DC-7B, as well as three fatalities on the ground, with an additional seventy injuries reported.
Findings
Investigation into the collision revealed that both aircraft were flying under clear weather conditions and following local VFR flight plans. The DC-7B and the F-89J were traveling on nearly opposing headings at 25,000 feet when they impacted near the Hansen Dam Spillway. At the moment of impact, the F-89J was banked approximately 30 degrees to the left.
Analysis determined that the high rate of closure speed prevented the pilots from having an adequate opportunity to avoid the other aircraft. The estimated closure speed was over 700 knots, leaving only about 15 seconds for avoidance once the aircraft became visible within a range of 3.5 miles. There was no evidence of mechanical failure or malfunction in either aircraft prior to the collision.