Project SIGN Investigation Report: Uniontown, Pennsylvania Sighting, 29 June 1948

This document is an investigation report compiled by the Air Materiel Command under Project SIGN regarding a series of unidentified aerial phenomena sightings in Uniontown, Pennsylvania, on the night of 29 June 1948. Multiple witnesses, including local civilians and a police sergeant, reported observing three luminous, oval-shaped objects that resembled halves of large meat platters. The objects were described as flying at an altitude of approximately 5,000 feet, traveling from the southwest to the northeast at a high speed. Witnesses noted that the objects appeared to be transparent, spun on their edges, and left a trail of light approximately one yard long. The sightings occurred during a period of stormy weather characterized by lightning and thunder. The investigation involved interviews with several witnesses, including a local newspaper reporter from the Pittsburgh Post-Gazette, and a review of weather data provided by the 102nd Weather Group. The report includes signed statements from the witnesses, which describe the objects' appearance and behavior in consistent terms. The official conclusion of the investigation was that there was no astronomical explanation for the incident. The report suggests that the phenomena might be related to ball lightning or, alternatively, a beacon searchlight projected against clouds, though it notes that the latter would typically remain visible at regular intervals. The document is marked as restricted and includes instructions for the handling of information related to the investigation, emphasizing the need to avoid publicity. It also contains an incident index from a Dr. Hynek's evaluation of the Project GRUDGE report, categorizing various incidents by their likelihood of astronomical or non-astronomical origins.