CASE FILE US-1957-001

RB-47 Electronic Intelligence Aircraft Encounter

17 July 1957 · Gulf Coast to Texas-Oklahoma flight corridor (near Duncanville, Texas) · Location generalized (Regional) · US

Official finding

The Condon Report's Case 5 concluded that "evaluation of the experience must, therefore, rest entirely on the recollection of crew members ten years after the event" and that "these descriptions are not adequate to allow identification of the phenomenon encountered." No contemporaneous 1957 written report by the crew or wing intelligence has been located.

Condon Committee (University of Colorado UFO Project, under USAF contract)

Scientific Study of Unidentified Flying Objects (Condon Report)

Anomaly Index assessment

Unresolved: corroborated

Three distinct and largely independent evidence channels, the crew's direct visual observation, an airborne ELINT receiver tuned to a specific microwave band, and separate ground-based air-defense radar at Duncanville, Texas, each registered a target consistent with the others at multiple points during a roughly ninety-minute, seven-hundred mile encounter, including reported instances of simultaneous appearance and disappearance across channels. That pattern of multi-channel correlation is the basis for the corroborated tier. The case is not classified as identified or likely identified because no single evaluated conventional explanation, including a later Air Force suggestion that the crew tracked an airliner, accounts for the reported cross-channel synchronization, and because the only detailed reconstruction available rests on crew recollection gathered a decade after the event, which is itself a serious limitation on the strength of the record.

Anomaly Index assessments are editorial evaluations of the public record. They are not official government determinations.

Unresolved means that the available evidence does not support a reliable identification. It does not imply extraterrestrial or nonhuman origin.

What was reported

In the early morning of July 17, 1957, an RB-47H reconnaissance aircraft of the 55th Strategic Reconnaissance Wing, flying out of Forbes Air Force Base, Kansas, on a composite training mission over the Gulf of Mexico and the south-central United States, encountered what its pilot, Major Lewis Chase, and copilot, Captain James McCoid, described as an intensely bright white light that closed rapidly from near their eleven o'clock position before abruptly changing direction and crossing their flight path. Chase told investigators he had never seen an angular rate of motion like it in twenty years of flying. Over the following hour and a half, as the aircraft flew north through Louisiana and Texas, the crew's electronic countermeasures monitors, tuned to search for a specific microwave signal, intermittently detected a strong signal at roughly 2,800 megacycles tracking counter to the aircraft's own motion; ground radar at the 745th Aircraft Control and Warning Squadron in Duncanville, Texas, independently picked up a target at the same general position and relayed it to the crew by radio under the callsign "Utah." Crew members reported several instances in which the visual light, the electronic signal, and the ground radar return appeared and disappeared together. The object was tracked, by varying crew accounts, into the Oklahoma City area or southern Oklahoma before contact was lost as the aircraft continued toward its home base in Topeka.

What is verified

An RB-47H of the 55th Strategic Reconnaissance Wing flew a composite training mission on July 17, 1957 that included electronic countermeasures exercises over the south-central United States.[3]
Air Defense Command forwarded summary information on the incident to Project Blue Book on October 25, 1957, more than two months after the event.[2]
The crew reported the object at various times by direct visual observation, by an airborne electronic countermeasures receiver, and by an independent ground radar station near Duncanville, Texas.[3]
No contemporaneous 1957 written report from the crew or wing intelligence has been located; the Condon Committee's detailed account was reconstructed from crew interviews conducted roughly a decade after the event.[3]

Evidence ledger

Evidence items documenting this case
Type	Description	Originality	Source organization	Released	Raw or edited	Metadata	Provenance	Known limitations	Source
Official document	Project Blue Book case file (case #10073) containing summary reporting and correspondence related to the incident.	Original	U.S. Air Force, Air Defense Command / Project Blue Book	1957	Unknown	Partial	Held at the National Archives, Record Group 341; digitized copy hosted by The Black Vault.	The file reflects a summary forwarded more than two months after the event rather than a contemporaneous incident report from the crew itself.	[2]
Radar	Ground radar detection at the 745th Aircraft Control and Warning Squadron, Duncanville, Texas, correlated by voice radio with the aircrew's own observations.	Derivative	U.S. Air Force Air Defense Command	1957 (event); 1969 (Condon Report reconstruction)	Unknown	No	Described in Condon Committee investigator Gordon David Thayer's 1969 case study, based on crew recollection and available correspondence; no original scope photography or radar log has been located.	No independently reviewable primary radar record survives; this item rests on secondhand reconstruction of the ground radar's contribution.	[3]
Multiple sensors	Reported instances of simultaneous or closely timed detection across the crew's visual observation, the aircraft's electronic countermeasures receiver, and ground radar.	Derivative	Condon Committee (University of Colorado UFO Project)	1969	Raw	Partial	Reconstructed from six crew members' 1967 interviews and available message traffic.	Ten years separated the event from the detailed interviews on which this reconstruction depends, and crew accounts of some specifics, including the exact endpoint of the pursuit, varied from one another.	[3]

Proposed explanations

Ground radar signal and equipment/interpretation error

Proposed by Philip J. Klass (skeptical analysis, cited in later commentary)

Supporting: Klass proposed the crew's ECM gear may have picked up ground radar signals, including from a training radar station at Keesler Air Force Base, and that the visual sighting was a separate, unrelated misidentification, such as a meteor.

Contradicting: Analyst Tim Printy and others have noted it is difficult to explain why a training radar at a fixed, known location would appear to move counter to the aircraft's own flight path and correlate with an independently reported visual object and a separate ground radar contact near Duncanville at the times described.

Disputed

Misidentified airliner

Proposed by U.S. Air Force spokesmen (later, undated public statements)

Supporting: Commercial air traffic was present in the region that night, and aircraft lighting can appear as a single bright light at a distance.

Contradicting: Condon Committee investigator Gordon David Thayer called the airliner explanation "literally ridiculous," citing the reported angular rate of motion, the object's apparent response coordinated across three separate detection channels, and the lack of any airliner correlated with the reported flight path and timing.

Rejected

Why this classification?

This case is classified as Unresolved: corroborated because the crew's direct visual observation, an airborne electronic intercept, and an independent ground radar station each reported a consistent target at multiple points across a ninety-minute, multi-state encounter, meeting the higher, multi-channel threshold for this category. It is not classified as insufficient data alone, despite the serious gap left by the missing contemporaneous 1957 report, because the Condon Committee's own investigator, working from crew interviews and available records, found no tested conventional explanation, including a later Air Force suggestion of a misidentified airliner, adequately accounted for the reported cross-channel correlation. Unresolved does not mean extraordinary or nonhuman; it means no reliable identification is currently supported.

What remains unknown

Whether a contemporaneous 1957 written report by the crew or wing intelligence still exists in an unprocessed file.
Whether the Duncanville ground radar's own logs from that night survive anywhere in Air Defense Command records.
The precise endpoint of the pursuit, which crew members recalled differently as near Oklahoma City or further south in Oklahoma.
Whether the 2,800-megacycle signal detected by the aircraft's ECM gear had any terrestrial source that has since gone unidentified in the public record.

Classification history

1957
Summary forwarded to Project Blue Book without identification (received October 25, 1957) — U.S. Air Force Air Defense Command
1969
Unidentified (Case 5); available descriptions "not adequate to allow identification of the phenomenon encountered" — Condon Committee (University of Colorado UFO Project)
2026
Unresolved: corroborated — Anomaly Index

Sources

Primary source: Tier A
Project BLUE BOOK — Unidentified Flying Objects (records collection) (opens in new tab)National Archives and Records Administration · 1947–1969 (records); collection description current
Source provenance note
Canonical archival collection for U.S. Air Force UFO investigations (Projects Sign, Grudge, and Blue Book). Individual case files are held in Record Group 341 and available on microfilm and through NARA's catalog.
Primary source: Tier A
Project Blue Book Case File — RB-47 Electronic Intelligence Encounter, July 17, 1957 (opens in new tab)U.S. Air Force, Project Blue Book (Record Group 341, National Archives and Records Administration) · 1957
Source provenance note
Digitized Project Blue Book case file (Blue Book case #10073). The original is held at the National Archives in Record Group 341. This digitized copy is hosted by The Black Vault, a public document archive of declassified U.S. government records obtained under the Freedom of Information Act and maintained by researcher John Greenewald Jr.
Primary source: Tier A
Scientific Study of Unidentified Flying Objects (Condon Report) (opens in new tab)University of Colorado (under U.S. Air Force contract) · 1968 · archived copy (opens in new tab)
Source provenance note
Air Force–commissioned academic study led by physicist Edward Condon. Contains detailed case analyses, including several the study itself left unexplained. Full text mirrored by the National Capital Area Skeptics with permission; the original was published by the University of Colorado in 1968 and in print by Bantam in 1969.