This case probably does deserve listing in the directory, because, although the USAF remained puzzled by the testimonies of the witnesses [I think that this is the one with all the chasing around after guys who were no longer "on station" and some remembered one thing and others another; and you get the impression that they are remembering different incidents and partial hearsay, etc]. Anyway, the thing[s] is [are] historical as it got Col.Beam and Al Loedding "out of the office" on what is, I think, the first long-distance Project field trip. Loedding wanted to go particularly not for this case but because he wanted to stretch it to get over to see the "Rhodes Photo" fellow in Phoenix.
The best references by far on this stuff are the Project reports by Beam. They are in the Holloman file in the microfilm, which Dan has put partially up --- but some of the best stuff goes on for several pages after "our" current last page, and probably should be included. Loren also quotes the better Beam quotes in his history for 1948. The case was well known locally and McLaughlin mentions it in his TRUE article [which diabolically I can't find at this moment --- another filing casualty of writing the big book]. I believe that this is where Ruppelt actually gets his brief info, and other folks [Hall/UFOE; Vallee; Haines/Delta;] simply repeat from there.
So the only really important reference is the Beam report[s] from the microfilm. Loren and McLaughlin are secondaries useful for "spice".
The field trip that Loedding took was in May 1948.
I think the Holloman File that Michael Swords speaks of begins here:
and continues until:
(this document mentions Lt Col James C. Beam.
This file covers this sighting
April 5,1948; Holloman AFB, New Mexico (BBU 139)
Afternoon. Geophysics Lab and/or AMC Watson Lab balloon observers Olsen, Johnson, Chance, saw 1 to 2 irregularly round, gray-white or golden objects, indistinct in outline like a majors insignia ... slightly concave on top, one [?] estimated 100 ft size. Both were rising straight up then one veered to the right, dropped, made a large loop, went upward again, then disappeared suddenly not due to distance. The other object arced off to the W at terrific or tremendous speed made 3 vertical loops or violent maneuvers then disappeared suddenly not due to fading away in the distance. (Berliner; cf. Ruppelt p. 71; Vallée?; Loren Gross Jan-July 1948 orig ed p. 25)