Declassified in 1997 as part of the GAO's investigation sponsored by the late Congressman Schift (Rep - New Mexico) in the Roswell incident, project SIGN began in 1947 as an Air Force investigation of UFOs, headed by Col. H. M. McCoy, Chief of Intelligence, Air Materiel Command, Wright Patterson AFB, Dayton Ohio. Project SIGN ended in early 1949 when the name was changed to Project GRUDGE, though Col. McCoy remained in charge of the successor project. The 900 pages of released documents are primarily UFO intelligence reports, some with good data and administrative correspondence, green fireball reports of 48-49 in the desert southwest. The Fund for UFO Research has an excellent summary of the Air Force's project SIGN documents.

At approximately 3.00 p.m. on the afternoon of 24 June 1947, pilot Kenneth Arnold had his now-classic UFO encounter near the Cascade Mountains, Washington State. According to Arnold, he viewed nine, elliptical-shaped objects flying in a wedge-like formation and stated that the objects flew as a saucer would if it were skimmed across a pool of water. The Flying Saucer mystery had begun. In the weeks and months after Arnold’s now-historic encounter, a wealth of other reports reached both the military and the media.

On 28 June, while flying at a height of 10,000 feet and 30 miles northwest of Lake Meade, Nevada, an Air Force Lieutenant reported seeing five or six white, circular-shaped UFOs in close formation and traveling at a speed of approximately 285 miles per hour. The following day, a party of three – including two scientists – reported seeing a large UFO near the White Sands Missile Range. They were able to keep the object in view for almost a full minute and described it as disk-shaped, moving at high speed and with no discernible wings.

On 7 July 1947, five Portland, Oregon, police officers reported varying numbers of disks flying over different parts of the city; and on the same day, William Rhoads of Phoenix, Arizona, saw an object not dissimilar to that reported by Kenneth Arnold. Seventy-two hours later, a Mr. Woodruff, a Pan-American Airways mechanic, reported seeing a circular-shaped UFO flying at high speed near Harmon Field, Newfoundland.

As the summer of 1947 drew to a close and the Air Force had become an independent entity of the military, Air Intelligence demanded a report from Air Materiel Command regarding the then-current opinions on "flying disks". Lieutenant General Nathan F. Twining, the Commander of the Air Materiel Command at Wright Field, held a conference with individuals attached to the Propeller Laboratories of Engineering Division T-3, the Air Institute of Technology, and the Office of Chief Engineering Division. The result was a 23 September 1947, memorandum sent by Twining to Brig. General George Schulgen, Chief of the Air Intelligence Requirements Division. It concluded that:

a. The phenomenon reported is something real and not visionary or fictitious.
b. There are objects probably approximating the shape of a disk, of such appreciable size as to appear to be as large as man-made aircraft.
c. There is a possibility that some of the incidents may be caused by natural phenomena, such as meteors.
d. The reported operating characteristics such as extreme rates of climb, maneuverability, and actions which must be considered evasive when sighted or contacted by friendly aircraft and radar, lend belief to the possibility that some of the objects are controlled either manually, automatically, or remotely.
e. The apparent common description of the objects is as follows:

(1) Metallic or light reflecting.
(2) Absence of trail, except in a few instances when the object apparently was operating under high performance conditions
(3) Circular or elliptical in shape, flat on bottom and domed on top.
(4) Several reports of well kept formation flights varying from three to nine objects.
(5) Normally no associated sound, except in three instances a substantial rumbling roar was noted.
(6) Level flight speeds normally above 300 knots are estimated.

f. It is possible within the present U.S. knowledge - provided extensive detailed development is undertaken - to construct a piloted aircraft which has the general description of the object in subparagraph (e) above which would be capable of an approximate range of 7,000 miles at subsonic speeds.
g. Any development in this country along the lines indicated would be extremely expensive, time consuming, and at the considerable expense of current projects and therefore, if directed, should be set up independently of existing projects.
h. Due consideration must be given to the following:

(1) The possibility that these objects are of domestic origin - the product of some high security project not known to AC/AS-2 or this Command.
(2) The lack of physical evidence in the shape of crash recovered exhibits which would undeniably prove the existence of these objects.
(3) The possibility that some foreign nation has a form of propulsion, possibly nuclear, which is outside of our domestic knowledge.

As a result, Air Materiel Command requested that a directive be issued assigning a permanent project to study the UFO phenomenon. On 30 December 1947, Major General L. C. Craigie, Director of Research and Development, issued an order that would establish Project Sign as the investigative body tasked with examining UFO reports. It would be the role of Sign to: “… collect, collate, evaluate and distribute to interested government agencies and contractors all information concerning sightings and phenomena in the atmosphere which can be construed to be of concern to the national security.”

During the first six months of 1948, Project Sign studied UFO reports at Wright-Patterson AFB and focused much of its attention on the possibility that some UFOs were, indeed, other-worldly in origin. On 5 August 1948, the Project Sign team determined that it was time for an evaluation of the data obtained. As a result, a Top Secret Estimate of the Situation was prepared by the US Air Force’s Air Technical Intelligence Center, which concluded that UFOs were interplanetary spacecraft. This was to cause widespread dismay and concern amongst the higher echelons of the military and the conclusions of the report were rejected, largely on the orders of Chief of Staff, General Hoyt Vandenberg, who argued that the Estimate was bereft of any firm evidence to support such beliefs. As a result of this, the ET-hypothesis lost favor within Sign; and those involved in the production of the report were rapidly reassigned alongside rumors of a lack of morale within the project.

Nevertheless, by the end of 1948, Project Sign had received several hundred UFO reports, of which 167 had been classed as “good”; and almost 40 of which were considered to be “unknown”. By 16 December 1948, however, the work of Sign (much of which supported the ET-hypothesis) came to a close; and Brigadier General Donald Putt changed the name and made way for the more debunking-oriented Project Grudge.

If the Estimate of the Situation report was rejected by General Vandenberg, one might ask, is that because the conclusion was based on faulty data or is there a more sinister scenario? It is known that the project only carried a 2A restricted classification (with 1A being the highest); and whilst the project could, under required circumstances, be assigned a higher clearance, this suggests strongly that Sign personnel did not have blanket need-to-know with respect to the UFO mystery. Interestingly, the author and investigator Kevin Randle has spoken with a U.S. colonel who had worked with ATIC in the late 1940s and who confirmed the existence of the Estimate of the Situation and was aware that it had been hand-delivered to Vandenberg.

According to the colonel, Vandenberg ordered that two paragraphs be removed from the Estimate – both of which referred to UFO crashes in New Mexico. Vandenberg’s actions seem to suggest that (a) Project Sign’s conclusions were being manipulated from the very beginning; and (b) there were those within the military that wanted Sign kept strictly out of the crashed UFO/Majestic 12 loop. (Watch Video HERE)