Updated: 26 Aug 2006:
Dan Wilson located the unsantized, secret version of one of the
documents. MAXW-PBB1-791 replaces MISC-PBB2-898, but both are presented
below.
Not listed in the Blue Book Unknowns, the Chop Clearance list has this
one as Item #28:
Feb. 1, 1953; Terre Haute, Indiana. Sighting of a UFO by a
T-33 pilot. All I've been able to find are three documents.
A military aircraft on a 270 heading 10 miles west of Terre Haute
sighted a close group of moving lights changing color from red to blue,
to green to yellow. The pilot estimated their altitude to range between
30,000 ft. to 15,000 ft. flying in a manner similar to conventional
aircraft. Searchlights from the St. Louis area seemed to be following
the unidentified lights. The time of sighting was about 2130 EST.