Type: Electronic Intelligence Records
Source: United States Air Force RB-47H Mission Records
The RB-47H Stratojet involved in the July 17, 1957 encounter was specifically designed to collect electronic intelligence (ELINT). Its onboard electronic warfare systems continuously monitored radar emissions encountered during flight, allowing crew members to identify, classify, and locate military radar systems across large distances.
During the mission, the aircraft's Electronic Warfare Officers reported repeatedly detecting an unidentified radar emission that could not be associated with known radar installations operating along the aircraft's route. The signal appeared intermittently as the aircraft traveled across Mississippi, Louisiana, Texas, and Oklahoma and demonstrated behavior inconsistent with fixed ground-based transmitters.
According to crew reports, the unidentified signal frequently appeared in conjunction with a brilliant bluish-white object observed outside the aircraft. At various points during the encounter, the electronic signal disappeared, only to reappear later from a different location while the object was again observed visually. Ground radar stations independently reported tracking unidentified targets during portions of the same event.
Project Blue Book investigators carefully reviewed the electronic intelligence observations because they represented instrumental evidence independent of eyewitness testimony. Investigators considered equipment malfunction, known radar systems, atmospheric propagation, electronic interference, and classified military operations but were unable to identify a conventional explanation that accounted for the complete sequence of observations.
The RB-47 ELINT records remain one of the most significant forms of instrumental evidence associated with any historical military UAP case. Unlike incidents based solely upon visual observations, the encounter involved specialized electronic surveillance equipment operated by trained military personnel whose primary responsibility was the identification and analysis of radar emissions.