What happened
During a local test flight conducted over Monterey Bay, a Convair aircraft carrying three crew members and eight NASA scientists was performing survey equipment testing. After completing its mission objectives, the aircraft began its approach to Moffett Airbase. While seven miles from the airfield, the crew received clearance to land on runway 32R.
Simultaneously, a US Navy Lockheed P-3C-125-LO Orion, registered 157332, was conducting a local training mission with six crew members on board. The Orion crew notified air traffic control that they were joining the approach path for runway 32L. During this sequence, the controller issued a new clearance to the Convair crew, instructing them to land on runway 32L instead of their original assignment.
As both aircraft progressed along their paths, the nose gear of the Convair struck the upper portion of the Orion's tail at an altitude of approximately 300 feet. The impact caused both aircraft to lose control. Both planes subsequently crashed into a golf course in Sunnyvale, located roughly 0.3 miles short of the runway threshold, where they caught fire upon impact.
Findings
Investigations revealed that the collision was driven by multiple errors made by the approach controller. The controller initially assigned different runways to each aircraft but subsequently cleared the Convair to land on the same runway as the Orion. While the Orion crew had confirmed their position on the 32L approach, the Convair crew did not query the sudden change in landing instructions. Additionally, neither flight crew was able to visually identify and avoid the other aircraft before the collision occurred.
The accident resulted in 16 fatalities and one serious injury.