C.A. Form 523 was the Departmental internal pro-forma for reports on aircraft accident investigations.

The cover shown at left is from the investigation into the accident to Australian National Airways' Avro X VH-UMF Southern Cloud, which disappeared en route from Sydney to Melbourne on 21 March 1931. The aircraft's wreckage was discovered in the Snowy Mountains by accident in October 1958, hence this report is done on an April 1956 revision of the C.A.523.

Accident reports were not pubished in this form as at this time they were not generally made publicly available, although the most important were summarised in the Department's fledgling Aviation Safety Digest.

(Report: CAHS/Edgar Johnston collection)