Supplementary Report of Unidentified Aircraft or Flying Object — Clark AFB, Philippines, 8 September 1949

This intelligence report, dated 4 October 1949, details a sighting of an unidentified aerial phenomenon that occurred on 8 September 1949, near Clark Air Force Base in the Philippines. At approximately 0400 hours, five officers from the 67th Fighter Squadron observed a high-speed object climbing at a 30-degree angle, leaving a dense, persistent con-trail. The object was described as a dark, black dot, which climbed rapidly to an altitude between 40,000 and 50,000 feet before leveling off and continuing on a northerly course. The witnesses, all experienced pilots, estimated the object's speed to be well over 1,000 miles per hour. Despite the presence of radar operations in the area, the object was not detected by ground radar. The report explicitly discounts the possibility that the con-trail was created by two F-51 aircraft that departed Clark AFB at 1135 hours, noting a significant time discrepancy between the sighting and the aircraft's flight path. The weather conditions at the time were reported as having thin high cirrus clouds, with no other aircraft reported in the vicinity at that altitude. The investigating officers concluded that they were unable to identify the object or the phenomenon that caused the con-trail. The report includes detailed statements from the witnesses, including Major Louis J. Sebille, 1st Lt. R. J. Semrau, 1st Lt. F. S. Welch, and 1st Lt. Harry C. Moore, all of whom provided consistent accounts of the object's behavior and appearance. The document also includes meteorological data and flight schedules, confirming that no other military or commercial flights could account for the sighting. The final assessment remains that the object's nature is unknown, and no physical evidence or photographic documentation was obtained.