Dear Mr. Bridges,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located series titled Aviation Unit Records, ca. 1965-1973 that include records of the 52nd Aviation Battalion in Boxes 337-338 and records of 227th Aviation Company (Assault Helicopter) in Box 501; Operational Reports - Lessons Learned (ORLL), 1965-1972 that includes records of the 52nd; and After Action Reports, 1965 - 1972 that include a file unit titled Air Assaults/Assault Helicopter Companies that may include records of the 227th. All three series are in the Records of the U.S. Forces in Southeast Asia (Record Group 472). We were unable to locate specific records of the 52nd Assault Helicopter Battalion.
For access to and/or copies of these records, please contact the National Archives at College Park - Textual Reference (RDT2) via email at firstname.lastname@example.org.
We hope this is helpful. Best of luck with your research!