1973 Sunnyvale mid-air collision

On April 12, 1973, a NASA Convair CV-990 and a US Navy Lockheed P-3 Orion collided on approach to Moffet Field, California. The two aircraft crashed on a golf course, killing all 11 on the CV-990 and 5 of the 6 on board the Orion.

One of the aircraft involved was 157332, a Lockheed P-3C Orion operated by the US Navy built in 1970. It was assigned to Patrol Squadron 47.^[1][2]

The other was N711NA, a Convair CV-990-30A-5 Coronado operated by NASA. The aircraft was built in 1961 and was modified into a flying observatory. The modifications included optically refined windows in the upper fuselage. The aircraft was nicknamed "Galileo".^[1][3]

The Orion departed for a training flight five and a half hours prior to the accident. The plane was flying over the ocean off Big Sur and then returned to Moffet Field to perform touch-and-go landings on runway 32L, which it continued to do for the next hour and a half. The CV-990 was returning from a two-hour flight over Monterey Bay where it was testing a system for surveying sea mammals.^[1][4]

The weather at the airport was good, with great visibility. At 14:46 local time, the CV-990 was cleared for approach to runway 32R. Three minutes later, the CV-990 was cleared to approach runway 32L, the runway the Orion was performing touch-and-go landings on. The pilot of the CV-990 replied "32L, thank you", and the pilot of the P-3 stated "...touch-and-go left side."^[1][4] The CV-990 was descending directly above the P-3, when, according to eyewitnesses, the P-3 initiated a climb. The CV-990 struck the P-3's upper aft fuselage at an altitude of 300 feet and the aircraft crashed entangled on the Sunnyvale Municipal Golf Course a kilometer short of the runway. All 11 on board the CV-990 and 5 of the 6 on board the P-3 died in the crash and ensuing fire.^{[1][4][5][6][7][8]}

The collision was a result of mistakes on part of the approach controller. The controller cleared the CV-990 for approach to a runway that the P-3 was already approaching. The crew of the CV-990 didn't question this runway change.^[1][4][7]