DOW-UAP-D100: "The Conclusion Appears Inescapable" - The Air Materiel Command and Project Sign File, 1947-1948

Source file: DOW-UAP-D100_Air-Materiel-Command-Report-on-UFOs_1947-1948.pdf Originating agency: U.S. Department of War; Headquarters United States Air Force (Directorate of Intelligence) and Air Materiel Command (AMC), Wright-Patterson Air Force Base Document type: Consolidated file of memoranda, formal Indorsements, cover sheets and public correspondence Date: 1947-1948 (the core of the file: 3 to 19 November 1948) Classification: Classified at the time (declassified; Authority NND57563) Page count: 245 VIRIN: 260807-D-D0360-1089 PURSUE Release: 5

Summary

This is the administrative correspondence file of Project Sign, the U.S. Air Force's first official UFO investigation program, established by direction of the Director of Research and Development at Headquarters USAF on 30 December 1947. The file contains hundreds of pages of memoranda, formal indorsements, routing sheets, control forms and letters from the public.

At its center is a short but decisive exchange. On 3 November 1948, Maj. Gen. Charles P. Cabell, the Air Force Director of Intelligence, sent a letter to the Commanding General of the Air Materiel Command. It opens with a sentence that has become one of the most quoted in the history of the subject: "The conclusion appears inescapable that some type of flying object has been observed." Cabell adds that the identification and origin of these objects is not discernible to his headquarters, and that efforts to determine whether they are of domestic or foreign origin must be increased until conclusive evidence is obtained, because "the needs of national defense require such evidence in order that appropriate countermeasures may be taken."

On 8 November 1948 the Air Materiel Command replied by first indorsement. The response reports a study of approximately 180 incidents, proposes a four-group shape classification, explicitly considers and rejects for lack of evidence the possibility of "vehicles from another planet," and recommends releasing nothing to the press about the objects the service cannot identify.

Research Article

Cabell's letter: urgency, not skepticism

The letter of 3 November 1948 appears in the file in three copies of varying scan quality, which makes it possible to reconstruct its text in full. It runs to four paragraphs, and each carries weight.

The first paragraph cites the source of authority: the letter of 30 December 1947 from the Director of Research and Development, by which Headquarters AMC was required to establish Project SIGN. The second paragraph is the core: "The conclusion appears inescapable that some type of flying object has been observed. Identification and the origin of these objects is not discernible to this Headquarters." From this follows the operational demand: efforts to determine whether the objects are of domestic or foreign origin must be increased until conclusive evidence is obtained, since the needs of national defense require such evidence so that countermeasures may be taken.

The precise wording repays attention. Cabell does not say that an alien craft has been observed, nor does he say that a Soviet craft has been observed. He says that the fact an object has been seen is inescapable, and that its identity is unknown to his headquarters. In intelligence terms this is a statement about a knowledge gap, and the urgency follows from it: you cannot develop countermeasures against something you cannot identify.

The third paragraph concerns the public, and is unusually frank: "To date there has been too little data to present to the public. The press, however, is about to take it into its own hands and demand to be told what we do or do not know about the situation. Silence on our part will not long be acceptable." The fourth paragraph requests immediate information on conclusions to date, and recommendations on what should be given to the press and whether it should be offered or withheld until actively sought.

The Air Materiel Command's reply: 180 incidents and four groups

The reply, sent just five days later, is an impressive document in its brevity and order. It opens with a statement of scope: "this Command has made a study of approximately 180 such incidents." The data did not rest on initial reports alone but were supplemented by further information obtained from check lists submitted by mail, from interrogations by other field agencies, and by personal investigation by Command personnel in cases that seemed likely to yield particularly significant information.

The proposed classification divides the objects into four groups according to shape or physical configuration: a flat disc of circular or approximately circular shape; a torpedo or cigar shaped aircraft with no wings or fins visible in flight; spherical or balloon shaped objects; and balls of light with no apparent form attached. This division remained in use in the literature of the subject for decades.

The Command reports that some of the objects were definitely identified, upon further investigation, as weather or upper air scientific balloons, and that a great many of the round or balloon shaped objects are probably of the same nature, although in most cases definite confirmation proved impossible to obtain. Other objects were identified as being astro-physical in nature; in daylight sightings, for instance, the planet Venus was reported as a round, silvery object at extremely high altitude. The Command reports that action is being taken to obtain the services of a prominent astro-physicist as a consultant, and that arrangements are being made in coordination with the Aero-Medical Laboratory at its headquarters for a study of the psychological problems involved, since the possibility that some sightings are hallucinations, optical illusions or even deliberate hoaxes had been considered.

The unexplained remainder, and Langmuir

The sixth paragraph is the most candid: "there remains a certain number of reports for which no reasonable everyday explanation is available. So far, no physical evidence of the existence of the unidentified sightings has been obtained." Here Dr. Irving Langmuir of the General Electric Company, a Nobel laureate in chemistry, is named as having been interviewed to determine whether he could advance any reasonable explanation for the characteristics exhibited by the objects. In an early interview Langmuir indicated that these incidents could be explained, but that insufficient data were available at that time on which to base definite conclusions. The Command plans a further interview with Langmuir to review all the data, hoping he will be able to offer an opinion on the nature of many of the unidentified objects, particularly those described as "balls of light."

The seventh paragraph contains an emphatic finding in the opposite direction: "All information that has been made available to this Headquarters indicates that the discs, the cigar shaped objects, and the 'balls of light' are not of domestic origin." The Command goes on to note that engineering investigation indicates a disc or wingless aircraft could support itself in flight by aerodynamic means, and that the problems of stability and control could probably also be solved, but that according to current aerodynamic theory in the United States, aircraft of such configurations would have relatively poor climb, altitude and range characteristics with the power plants then in use.

"Vehicles from another planet"

The eighth paragraph is perhaps the most famous in the reply: "The possibility that the reported objects are vehicles from another planet has not been ignored. However, tangible evidence to support conclusions about such a possibility are completely lacking."

An intriguing detail follows immediately. The Command plotted the occurrence of incidents in relation to the approach to the earth of the planets Mercury, Venus and Mars, and found a periodic variation in the frequency of incidents that appears to bear some relation to the planet approach curves, "but it may be purely a coincidence." The ninth paragraph refers to "The Books of Charles Fort," published in 1941 by Henry Holt, and remarks that it appears similar phenomena have been noted and reported for the past century or more. Both references, inside an official military intelligence document, illustrate how wide the range of explanations seriously entertained in 1948 actually was.

The three conclusions and the recommendation of silence

The conclusions are set out in three parts. First, in the majority of cases reported, observers have actually sighted some type of flying object which they cannot classify as an aircraft "within the limits of their personal experience." Second, "There is as yet no conclusive proof that unidentified flying objects, other than those which are known to be balloons, are real aircraft." Third, although it is obvious that some types of flying objects have been sighted, the exact nature of those objects cannot be established until physical evidence has been obtained, "such as that which would result from a crash."

The eleventh paragraph is the press recommendation, and it is stated plainly: it is not considered advisable to present to the press information on those objects which the service cannot yet identify or about which it cannot present any reasonable conclusions. In the event the press insists on some kind of statement, it is suggested they be informed that many of the objects sighted have been identified as weather balloons or astral bodies, and that investigation is being pursued to determine reasonable explanations for the others.

The file also contains the actual draft of that statement: "Investigation by United States Air Force of reports on so-called flying saucers has led to the identification of some of these objects as weather balloons and astral bodies. The investigation of such reported incidents is continuing at the Air Materiel Command, Wright-Patterson Air Force Base, Dayton, Ohio." Alongside it appears a recommendation of 19 November 1948 addressed to General Cabell: "AFOAI recommends that no statement be released to the press on flying object incidents until press demands make such release imperative."

The gap between the two halves of the file is its central finding: in the same month in which it was written internally that the conclusion an object had been seen was inescapable and that its origin was not domestic, the outward recommendation was to concentrate on those cases that had in fact been explained.

Around the core: airline pilots and letters from the public

The remainder of the file documents the everyday machinery of the project. One strand of correspondence concerns the recruitment of civil airlines: Colonel Robert Taylor 3rd, Chief of the Collection Branch in the Air Intelligence Requirements Division, works with the Air Transport Association to develop a system by which U.S. airline pilots could make reports of any unusual aerial sightings direct to headquarters. The Air Materiel Command replies on 26 October 1948, requesting cooperation in distributing an "Essential Elements of Information" check list for use by commercial airlines as a supplement to publication JANAP 146, developed by the Joint Communications-Electronics Committee for the reporting of "flying disc" sightings. The reply is signed for Colonel H. M. McCoy, Chief of the Intelligence Department at AMC.

Other portions of the file include correspondence on the Horten brothers' German tailless aircraft and a T-2 report on German flying wings, reflecting the line of inquiry that sought to establish whether the discs were captured German technology developed further. And alongside the official memoranda the file preserves letters from private citizens. One, from Hiawassee, Georgia, dated 14 September 1948, asks the War Department to say what the things are that people in North Georgia have been seeing flying through the sky: "They are round and long some what like a giant cigar. They have a motor that sounds like a motorcycle." The writer adds that if they are foreign machines the Department should know about it, and that if they are American military machines he does not need to know. That combination of top-level memoranda and citizens' letters in a single file illustrates exactly the situation Cabell described: mounting public pressure against a headquarters that had no answer.

Significance

The file's importance is twofold. First, Cabell's letter is one of the most explicit official statements ever written by a senior American intelligence officer on the subject: not an admission of foreign technology, but a finding that something had been seen and that the system did not know what it was, coupled with an operational demand to obtain evidence. Second, the Air Materiel Command's reply demonstrates what an orderly intelligence assessment on the subject looked like in 1948: 180 incidents, a shape classification, an approach to a Nobel laureate, a psychological hypothesis under test, plotting against planetary approach curves, and an explicit consideration and reasoned rejection of the extraterrestrial hypothesis.

The file completes the founding documents already in the archive: the Project Sign progress report and the joint Intelligence Study No. 203 (1948 draft and 1949 edition), released in PURSUE Release 4, and the O'Brien Committee file reviewing Project Blue Book. The summarizing report announced in the reply's final paragraph, "A report, summarizing the results obtained from analysis of the data and a technical investigation of the engineering aspects of the objects described, is nearly complete," is precisely that Intelligence Study No. 203 already held in the collection.

Key People

Locations

Incidents

Notable Quotes

"The conclusion appears inescapable that some type of flying object has been observed. Identification and the origin of these objects is not discernible to this Headquarters." -- letter of 3 November 1948

"The needs of national defense require such evidence in order that appropriate countermeasures may be taken." -- letter of 3 November 1948

"The press, however, is about to take it into its own hands and demand to be told what we do or do not know about the situation. Silence on our part will not long be acceptable." -- letter of 3 November 1948

"In attempting to arrive at conclusions as to the nature of unidentified flying object incidents in the United States, this Command has made a study of approximately 180 such incidents." -- first indorsement, 8 November 1948

"All information that has been made available to this Headquarters indicates that the discs, the cigar shaped objects, and the 'balls of light' are not of domestic origin." -- first indorsement, paragraph 7

"The possibility that the reported objects are vehicles from another planet has not been ignored. However, tangible evidence to support conclusions about such a possibility are completely lacking." -- first indorsement, paragraph 8

"There is as yet no conclusive proof that unidentified flying objects, other than those which are known to be balloons, are real aircraft." -- first indorsement, paragraph 10b

"The exact nature of those objects cannot be established until physical evidence, such as that which would result from a crash, has been obtained." -- first indorsement, paragraph 10c

"AFOAI recommends that no statement be released to the press on flying object incidents until press demands make such release imperative." -- memorandum to General Cabell, 19 November 1948