65 HS1-834228961 62-HQ-83894 Serial 164

This FBI file serial from case 62-HQ-83894 holds several copies of Air Intelligence Requirements Memorandum Number 4, "Unconventional Aircraft." Major General C. P. Cabell, Director of Intelligence at Headquarters United States Air Force, issued the memorandum on 15 February 1949. It sets continuing Air Force requirements for information on unidentified flying objects, including "Flying Discs," and tells commands to send reports to Air Materiel Command at Wright-Patterson AFB. It also includes a detailed checklist covering sighting details, observers, radar data and physical evidence, and the FBI Director appears on its distribution list.

From the source:Release of 2026-05-08 Incident: N/A, N/A. The FBI's 62-HQ-83894 case file includes investigative records, eyewitness testimonies, and public reports concerning Unidentified Flying Objects and flying discs documented between June 1947 and July 1968. The records include high-profile incident accounts, photographic evidence from sites like Oak Ridge, TN, and technical proposals regarding potential propulsion systems. Additional topics include convention programs, researcher accounts, and extensive media coverage from the period. This file is partially posted on FBI vault with more redactions and some pages missing. Included here is the complete case file with several newly declassified pages and only minor redactions.

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c. Odor (if any).
d. Rate of evaporation.
e. Does trail vary with sound? (spurts)
12. Effect on clouds.
a. Opened path thru clouds.
b. Forced cloud or mists .
c. Reflected on cloud.
d. Showed thru cloud.
13 , Lights.
a. Reflected or attached.
b. Luminous
c. Blinked on and off Ln r elation to speed.
14. Support
a. Wings.
b. Aerodynamic list of fuselage .
c. Vertical jet.
d. Rotating cylinder or cone.
e. Aer ostatic lift (balloon or dirigible) .
15. Propulsion.
a . P r opeller or jet.
b. Rotor.
c . Aerodynamic vanes (flapping or oscillating) (Katz Mayer effect).
d. Visible exhaust or jet openings.
16. Control and stability.
a. Fins
b. StabiUzers (hor izontal or vertical).
(1) Size.
(2) Shape .
(3) Location.
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