On July 17, 1957, a U.S. Air Force RB-47H electronic reconnaissance aircraft, during a routine training flight over Mississippi and Texas, encountered an unidentified flying object confirmed by all onboard equipment. This case is particularly notable because the RB-47 was the U.S. Air Force’s most advanced electronic reconnaissance platform at the time, equipped with numerous sophisticated detection instruments.

📍 Location	📅 Date	🔍 Category
Mississippi to Texas, USA	1957-07-17	Radar-Visual-EW

Three officers onboard simultaneously reported: visually observing a massive, white, luminous object; the aircraft’s Electronic Countermeasures (ECM) receiver detecting a “very strong signal”; and the tail warning radar tracking an unidentified target moving behind the aircraft.

Specifically regarding the ECM system—designed to detect enemy radar signals—it clearly indicated that the object emitted a series of intense pulse signals. Strangely, the frequency and pattern of these signals had never been recorded by the U.S. Air Force. Simultaneously, the tail warning radar showed the target moving within a range of approximately 8 to 20 kilometers behind the aircraft.

The duty pilot, Colonel Lewis D. Chase, stated in a post-incident interview: “I’ve flown for the Air Force for many years and have never seen anything like it. It seemed to be playing with us—whenever we tried to activate the ECM system to pinpoint it, it would immediately change position.”

Even more impressive was the UFO’s maneuverability, far exceeding any known aircraft of the time. According to flight records, the object could execute sharp turns exceeding 15 Gs—a G-force completely unsustainable for the human body. In contrast, the RB-47’s pilots could withstand only about 5 Gs.

The U.S. Air Force’s Project Blue Book recorded this incident as “unexplained.” To this day, it remains considered one of the best-documented and most reliable UFO contact events in history. Declassified CIA documents later cited this case.

📚 Sources

• U.S. Air Force, “RB-47H Electronic Reconnaissance Incident Report” (1957)
• Project Blue Book, Case File No. 3988
• CIA, “UFOB Incident: RB-47” (1957), Declassified 1995
• Ruppelt, E. “The Report on Unidentified Flying Objects” (1956/1960)