This historical Australian newspaper article contains the keyword "mystery aeroplane": 25 Jan 1933, "The Lure of Centralia": http://nla.gov.au/nla.news-article165959538
The Lure of Centralia - Sydney Mail (NSW : 1912 - 1938) - 25 Jan 1933
HARDLY had the trek back from the ill-fated Granites finished before word was flashed across the continent that Paddy Whelan's mystery aeroplane expedition had met with disaster. Fortunately death did not come the way of the party; ...