CASE FILE D-100
"Silence On Our Part Will Not Long Be Acceptable" - The 1948 Air Force Letter - Case D-100
2026-09-10 · Declassified UAP records
On 3 November 1948, Major General C. P. Cabell, the Air Force's Director of Intelligence, sent a letter marked SECRET from Headquarters USAF in Washington to the Commanding General of Air Materiel Command at Wright-Patterson Air Force Base in Dayton, Ohio. The subject line read: Flying Object Incidents in the United States.
Ten months earlier, by a letter dated 30 December 1947, Wright-Patterson had been ordered to establish Project "SIGN" - the first formal U.S. Air Force effort to investigate flying object reports, and the direct ancestor of Project Grudge and Project Blue Book.
Paragraph two is the reason the letter is still quoted today: "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." Cabell frames it as a national defense problem - efforts to determine whether the objects are of domestic or foreign origin "must be increased until conclusive evidence is obtained," so that "appropriate countermeasures may be taken."
Paragraph three turns to the public. "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." Cabell then asks Air Materiel Command for its conclusions to date, and for a recommendation on whether information should be offered to the press or withheld until the press actively sought it.
The letter is one page of a 245-page Air Materiel Command file on flying object incidents from 1947 and 1948, released in the PURSUE disclosure. The signed original is below, transcribed in full, followed by the narration transcript and the location of the headquarters it was addressed to.
The Document
SECRET (declassified - authority NND57563) 3 November 1948
USAF Headquarters Letter - Flying Object Incidents in the United States (3 November 1948)
- DEPARTMENT OF THE AIR FORCE - HEADQUARTERS UNITED STATES AIR FORCE - WASHINGTON
- 3 NOV 1948
- SUBJECT: Flying Object Incidents in the United States
- TO: Commanding General, Air Materiel Command, Wright-Patterson Air Force Base, Dayton, Ohio
1. By letter dated 30 December 1947 from the Director of Research and Development, Headquarters USAF, your Headquarters was required to establish Project "SIGN".
2. 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. It is imperative, therefore, that efforts to determine whether these objects are of domestic or foreign origin must be increased until conclusive evidence is obtained. The needs of national defense require such evidence in order that appropriate countermeasures may be taken.
3. In addition to the imperative need for evidence to permit countermeasures, is the necessity of informing the public as to the status of the problem. 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.
4. Request immediate information as to your conclusions to date and your recommendations as to the information to be given to the press. Your recommendation is requested also as to whether that information should be offered to the press or withheld until it is actively sought by the press.
BY COMMAND OF THE CHIEF OF STAFF: C. P. CABELL, Major General, USAF, Director of Intelligence, Office of Deputy Chief of Staff, Operations.
Released in the PURSUE disclosure as part of the Air Materiel Command file on flying object incidents, 1947-1948. The file runs to 245 pages; the letter below is the signed original, which appears in the file alongside carbon copies. No redactions. · Department of the Air Force, Headquarters United States Air Force, Washington (DoW-UAP-D100)
Where It Happened
Full Transcript
Third of November, nineteen forty eight. A letter marked secret leaves Air Force headquarters in Washington for Wright-Patterson, in Dayton, Ohio. Subject: flying object incidents in the United States.
Ten months earlier the Air Force had been ordered to stand up a project to investigate them. Code name, SIGN.
Paragraph two. 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.
Efforts to determine whether they are of domestic or foreign origin must be increased, he writes, until conclusive evidence is obtained, so that appropriate countermeasures may be taken.
Then paragraph three. The press 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.
He asks whether to offer that to the press, or wait until the press comes asking. Signed, C. P. Cabell, Major General, Director of Intelligence.
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Sources
All documents and footage are authentic, public-domain U.S. government releases. Narration is AI-generated text-to-speech.