NAA: MP1049/1, 1918/066, page 556 is an extract from a weekly military intelligence report compiled for the Australian section of the Imperial General Staff, which has been forwarded on to the Navy. (It contains information up to 30 March, but it's possible that it was compiled a day or two later.) It summarises a report by D. Burke, a schoolteacher from Raminea, Port Esperance, near the southern tip of Tasmania, of sounds heard in the air on 22 March (the day after Constable Wright's sighting at Nyang). Out of the 11 or so witnesses, 10 thought it sounded like 'an immense flock of birds', but one that 'resembled the sound of an engine', travelling south to north. After whatever it was had passed, two guns were heard firing far off to the south-west. It was a cloudy day and nothing could be seen.
Even though Burke was not the one who thought he heard an engine sound, it was his opinion 'that it was an aeroplane, and that it rejoined the parent ship about Port Davey'. The District Naval Officer was informed 'immediately' (presumably meaning 23 March, when Burke made his report), but he thinks the gunfire could be explained by thunder, or 'settlers [...] blowing out the stumps of trees', or blasting being carried out a carbide factory near Raminea. Or a party of prospectors from Melbourne. 'It is considered improbable that there is any foundation in fact for the reports', but the police are being asked to make further inquiries.
At the bottom of this extract there is a paragraph that has been crossed out, presumably because it's not about a mystery aeroplane sighting and so shouldn't be here (a pencil annotation reads 'See Proper File'). It's actually about a mystery submarine sighting, also from Tasmania but further up the east coast:
The people of Falmouth have seen that [sic] they think to be a submarine. It was above water for a short time only. It was travelling quickly, going South, and appeared to be going very steadily. There was one upright [i.e. a rod or pipe] at the end of it, and two more close together -- three altogether. It was seen at 8 a.m today [27 March]. Do not know distance from shore or color. Mr. Fitzgerald saw it first. Six or seven saw it altogether. These people were all at Steele's boarding-house, Falmouth.
A submarine was even less likely than an aeroplane: both of the RAN's had been lost in the first year of the war, and no German submarines had ever ventured anywhere near Australia (though one did in the next war). At least there was a German ship with a seaplane in Australian waters at one point in 1917. While I haven't found much evidence to suggest that there was a mystery submarine scare, there were enough stories to be lampooned in the press and this sighting probably should be thought of as being part of the larger defence panic which Australia was about to experience. Not that I made this argument in my article; I referred only to the aeroplane heard near Port Esperance as an early example of a post-Nyang mystery aeroplane. It would also been useful as an early example that members of the public were concerned that a Wolf-like ship was carrying a seaplane was off the coast, but I didn't mention that either.
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