The Fort Monmouth radar case: a T-33 crew’s object over Sandy Hook (1951)

A radar contact, then a visual sighting

An Air Force status report covers a series of visual and radar sightings reported around Fort Monmouth, New Jersey, on September 10 and 11, 1951. At about 1110 that first morning, according to the report, a radar set at the Fort Monmouth training center picked up a fast, low target to the southeast, which the operator could not track with automatic azimuth tracking. The report is careful about this: the radar sightings were made by maintenance students, not trained operators, and no plotting records or logs were kept. It concludes that the operator, who was demonstrating the set for visiting officers, was probably flustered, and that his own timings give a speed of about 400 mph rather than the 700 he assumed.

About twenty-five minutes later, at roughly 1135, an Air Force lieutenant flying a T-33 trainer from Dover Air Force Base, Delaware, to Mitchell Air Force Base, New York, saw an object off to his left. The report places the object over Sandy Hook, between 5,000 and 8,000 feet, with the T-33 itself near Point Pleasant. The pilot began a descending 360-degree turn to try to identify it. Some forty-five seconds later his passenger, an Air Force major who had been making a radio check, saw it too, by then near Freehold and turning toward the coast. The object was lost as it crossed the coastline.

“Round and silver … did not reflect the sunlight”

The report describes the object as “round and silver in color but did not reflect the sunlight,” and says that at one point during the attempted intercept “it appeared flat.” Its size was judged at 30 to 50 feet across. During the chase the T-33 went from 450 to 550 mph and descended from 20,000 to 17,000 feet.

The Air Force’s own doubts about its balloon theory

Investigators looked hard at a simple explanation. At about 1112 that morning, two balloons had been released from the Evans Signal Laboratory. They were 7 to 8 feet across at release, painted silver for radar tracking, and, as the report notes, experienced observers say such balloons can look disc-shaped from certain angles. By 1135 they would have been near the line between Point Pleasant and Sandy Hook.

The report states that attempts were made “to prove that the pilot and passenger of the T-33 had observed a balloon,” but that “not all of the data given was consistent with such a conclusion.” The crew was interrogated twice and gave different flight paths each time. The report also concedes that the object’s apparent descent when first sighted “cannot be explained.” After laying out the assumptions needed to make the balloon theory work, it ends this section by saying that because those assumptions were necessary, “it cannot be concluded that the object was definitely a balloon.”