Incident #28 - Operation Interloper Recent Reports

This document, titled Incident #28 under the Operation Interloper series, details a radar sighting reported by Lt. Thomas A. Featherstone of the USN, Class IX, Naval Intelligence School. In early May 1952, while operating GCA equipment at NAS Willow Grove, Pennsylvania, under poor weather conditions (250-foot ceiling and less than one mile visibility), Lt. Featherstone observed an unidentified target on his radar scope. The object was detected near the center of the scope and, by the fourth sweep of the radar, had moved to the 10-mile limit. Based on the equipment's 32 rpm rotation, the object's speed was calculated at approximately 3,600 mph. The target followed the northeast leg of the NAS range before disappearing on a 060-degree course. The contact was verified on both the primary and secondary director scopes. The following morning, a second fast-moving target was detected on a bearing of 120 degrees, heading toward the range station. Upon interception, this object also changed course to 060 degrees and followed the range to the limit of the scope. The report notes that the GCA equipment at NAS Willow Grove utilizes two independent radar channels, A and B, and that the search antenna is designed to prevent reception above 6,000 feet, though it can reach 8,000 feet during inclement weather.