Project 10073 Record Card and Air Intelligence Information Report — 18 April 1952

This document is an Air Intelligence Information Report (IR-20-52) dated 14 June 1952, concerning an unidentified flying object sighting in Japan on 18 April 1952. The report details a radar observation made by personnel at Detachment 21, 618th Aircraft Control and Warning Squadron, Japan Air Defense Force. The object was detected on a TPS-13 type radar using the L band and appeared on a Plan 12 Indicator. The sighting lasted for two minutes, from 1207-I to 1209-I. The object was estimated to be 5 to 8 degrees in length and 1/2 mile in width, traveling at an estimated speed of 2700 miles per hour. Its flight path began with a heading of 002 degrees, shifted to 310 degrees, and finally to 280 degrees before fading from the scope. The report notes that the radar set was operating normally before and after the incident, though maintenance personnel could not verify the equipment's status during the brief event. The geographic coordinates of the observation were 129°51'E/34°19'N. Weather conditions were described as fair with calm seas and approximately 5 miles of visibility with haze. The report explicitly states that there was no physical evidence, no unusual conditions that might account for the sighting, and no interception action taken. The radar operator involved was considered reliable with six months of experience. The official conclusion, provided by 'Electronic's opinion' and signed by Capt James, states that due to the short duration of the target, an acceptable explanation is impossible. The document includes a drawing of the track on the scope and is signed by Major Allen G. Dunken of the D/I FEAF. It was approved by Brigadier General Charles I. Baufill, Deputy for Intelligence.