Sighting Investigation Forms generated by Project SIGN
1. "Guide to Investigation: Unidentified Aerial Objects" (4 pp.)

2. "Essential Elements of Investigation: Unidentified Aerial Objects (EEI)" (6 PP)

During the summer of 1948, Project SIGN began seeking radar-UFO information from Air Force bases and facilities. The communications included:
3. Letter to Tinker AFB, Oklahoma    18 June 48  (1 p.)

4. Reply from Tinker AFB    7 July 48   (2 pp.)

5. Letter from Watson Labs, Red Bank, N.J.     30 July 48  (1 p.)
http://www.nicap.org/docs/sign_480730.htm

Sighting investigation, Pittsburgh, Pa.
6. Letter    6 Aug 48   (2 pp.)
SIGN learned that Brig. Gen. Erik K. Nelson, AFRes, had knowledge of UFO sightings over Sweden during 1948. An interview revealed that objects seen over Scandinavia included cigars, discs, and "large, ball-shaped object that could stop, hover, and go off at terrific speed."

7. USAF letter to Brig. Gen. Nelson    27 Aug 48   (1 p.)

8. SIGN letter to USAF Hdq re: interview       1 Oct 48   (2 pp.)

Sighting investigations, Los Angeles area
9. Letter to Procurement Field Office         8 Sept 48   (2 pp.)

10. Letter to March AFB, Riverside, Calif.     8 Sept 48  (2 pp.)

Letters to Air Defense Command seeking radar data
11. Letter to Mitchel AFB, N.Y.    16 Sept 48  (1 p.)
http://www.nicap.org/docs/sign_480916.htm

12. Reply from Mitchel AFB    15 Oct 48   (1 p.) 10 to 50 % of targets on their scopes are unidentified!
http://www.nicap.org/docs/sign_481015.htm

Letters to other intelligence agencies requesting assistance in identifying possible objects "of domestic origin."
13. Letter to CIA via Air Force Hdq    7 Oct 48   (2 pp.)
http://www.nicap.org/docs/sign_481007.htm

14. Letter to Director of Intelligence, Army    7 Oct 48   (1 p.)
http://www.nicap.org/docs/sign_481007c.htm

15. Letter to Office of Naval Intelligence     7 Oct 48   (1 p.)
http://www.nicap.org/docs/sign_481007d.htm

National and international instruction to all major commands "to be particularly alerted at this time for sightings of unidentified aerial objects..."
16. Air Force Hdq letter to SIGN    13 Oct 48   (1 p.)
http://www.nicap.org/docs/sign_481013.htm

Sighting investigation, New Orleans, La.
17. Letter to Army CIC detachment    18 Oct 48   (1 p.)

SIGN request for study by RAND Project; some UFOs possibly "experimental spaceships."
18. Letter to Air Force Hdq    22 Oct 48   (2 pp.)
http://www.nicap.org/docs/sign_481022.htm

19. Letter to RAND Corporation    10 Jan 49   (1 p.)
http://www.nicap.org/docs/sign_490110.htm

Sighting investigation, South Bend, Ind.
20. Letter to 12th OSI District, Scott AFB, 111. 22 Oct 48   (1 p.)

21. Cover letter, OSI investigation report     5 Jan 49   (1 p.)

Sighting investigation, Chicago, 111.
22. Letter to Hdq Fifth Army, Chicago         2 Nov 48   (1 p.)

23. Cover letter, Army investigation report    7 Jan 49   (1 p.)
http://www.nicap.org/docs/sign_490107.htm

Exchange between Maj. Gen. C.P. Cabell, Air Force Director of Intelligence, and Project SIGN. Cabell stated, "The conclusion appears inescapable that some type of flying object has been observed. Identification and origin of these objects is not discernible to this Headquarters."
24. Cabell letter to SIGN    3 Nov 48   (1 p.)
http://www.nicap.org/docs/sign_481103.htm

25. Col. McCoy reply to Chief of Staff   .     8 Nov 48   (3 pp.)
Sighting investigation, Neubiberg AFB, Germany
http://www.nicap.org/docs/sign_481108.htm

26. Letter re: 11 & 24 Oct 48 sightings       4 Nov 48   (1 p.)

Sighting investigation, F-61 radar-visual, 15 Oct 48, Japan
27. Letter to Far East Air Force commander     9 Nov 48   (2 pp.)

Correspondence with Dr. George E. Valley, Jr., M.I.T. and Air Force Geophysical Lab, Cambridge, Mass.
28. Letter to Valley with UFO incident summaries 29 Nov 48   (2 pp.)
http://www.nicap.org/docs/sign_481129.htm

29. Follow-up letter to Valley    2 Dec 48   (1 p.)
http://www.nicap.org/docs/sign_481202.htm

30. Letter to Air Force Lab with summaries     6 Dec 48   (1 p.)
http://www.nicap.org/docs/sign_481206.htm

31. Follow-up letter to Air Force Lab        21(?)Jan 49 (1 p.)
http://www.nicap.org/docs/sign_490121.htm

Communications with Hdq Air Defense Command (ADC) and Continental Air Command (CAC), Mitchel AFB, N.Y., regarding radar UFO sightings, especially those showing "unusual or outstanding flight characteristics...." and directives for reporting.
32. Utter from Hdq, ADC    15 Oct 48   (1 p.)
http://www.nicap.org/docs/sign_481015.htm

33. Letter to Commanding General, ADC        30 Nov 48  (2 pp.)
http://www.nicap.org/docs/sign_481130.htm

34. Letter from Hdq, CAC (with 12 Jan 49 reply)  3 Jan 49   (3 pp.)
http://www.nicap.org/docs/sign_490103.htm

35. Letter from Hdq, CAC    21 Feb 49   (1 p.)
http://www.nicap.org/docs/sign_490221.htm

Transmittal of SIGN incident summaries to Hdq, U.S. Air Force
36. Letter to Chief of Staff, Air Force, AFOIR  2 Dec 48   (1 p.)
http://www.nicap.org/docs/sign_481202.htm

Sighting investigation, 29 July 48, Indianapolis, Ind., Project SIGN Incident #151
37. Query to General Electric Corp.    2 Dec 48   (1 p.)

Transmittal of SIGN incident summaries to Navy
38. Letter to Office of Naval Intelligence     13 Dec 48  (1 p.)
http://www.nicap.org/docs/sign_481213.htm

Contract for scientific consultant to investigate UFO reports
39. Letter to Dr. J. A. Hynek, Ohio State Univ.  20 Dec 48   (2 pp.)
http://www.nicap.org/docs/sign_481220.htm

Status reports to Hdq, Air Force, on UFO investigation at Wright-Patterson AFB, Dayton, Ohio
40. Memorandum to Chief of Staff, Air Force     9 Feb 49   (2 pp.)
http://www.nicap.org/docs/sign_490209.htm

41. Memo to Director, R&D, re: Project GRUDGE   10 Mar 49   (2 pp.)
Transmittal of Project SIGN Technical Report No. F-TR-2274-IA, "Unidentified Aerial Objects: Project 'Sign'" to R&D Board, Washington, D.C.
http://www.nicap.org/docs/sign_490310.htm

42. Letter to Committee on Guided Missiles     19 May 49   (2 pp.)
http://www.nicap.org/docs/sign_490519.htm