Project 10073 Record Card and CIRVIS Report - 27 September 1961

On September 27, 1961, a series of radar sightings occurred off the Pacific Coast, documented through a Project 10073 record card and associated Air Force staff messages. At approximately 1557Z, a radar operator aboard an aircraft (identified as ETHAN 43) detected five unidentified objects on their scope. These objects were observed moving at high speeds, with one measured at 1800 knots over a distance of 200 nautical miles, before disappearing into sea clutter. Three minutes later, two additional objects were tracked moving across the scope, followed by the appearance of a single stationary object. The radar system used was an APS-95, and it was noted that the objects could only be detected when the IFF (Identification Friend or Foe) system was active. The weather conditions were reported as clear with no temperature inversion, ruling out atmospheric anomalies. A subsequent investigation identified that seven units of the USN PHIBRGN FIVE (consisting of two LSDs, three APAs, and two AKAs) were operating in the area, en route from Fort Lewis, Washington, to San Diego, California. These ships were visually sighted by the crew of ETHAN 43 at 1824Z. The official conclusion reached by the Air Force was that the radar returns were likely the result of electronic interference from these ships, rather than an unidentified aerial phenomenon.