Australia and Papua New Guinea
Short Paid Aerogramme

This aerogramme of Australia (Stein A-2) was sent to Woking, United Kingdom, on August 21, 1955. 

Australian stamps and airletters were valid in Papua New Guinea until March 2, 1953. On October 30, 1952  and April 17, 1953, respectively, endemic stamps and airletters were introduced.

The sender added a 3d stamp to meet the 10d airletter rate. The Australian aerogramme was not accepted, so the airletter was short paid 7d. Double the deficiency (1s2d) was converted into 42 UPU gold centimes at a rate of 1d = 3 UPU gold centimes as is endorsed in manuscript between the "By Air Mail" routing instruction and the Bristish postage due handstamp.

The same conversion rate was in place for the British currency, which explains the 1s 2d postage due handstamp.


Credits
The scan of this aerogramme was provided by Luc Jacquemin. Thanks!

References
Stein refers to Stein, The Aerogrammes of Australia and its Dependencies, 1944-1980