In March 1929 the Controller of Civil Aviation, Lt Col Horace Brinsmead, wrote to the owners of all the aircraft on the Australian civil Register to inform them of the need to change their aircraft's registration markings. This copy of the standard letter was sent to Charles Kingsford Smith and Charles Ulm in relation to their aircraft, the famous Fokker F.VIIb-3m Southern Cross.

The Southern Cross had arrived in Australia on 9 June 1928 following the famous trans-Pacific flight wearing its United States registration, NC1985. It was re-registered on the Australian Register in the original registration marks series as G-AUSU on 4 July. The aircraft had therefore only worn these marks for less than a year when the letter requiring a change to VH-USU in the new series was sent.

As the letter says, aircraft owners were given a year to change their markings to the new system. However, aircraft used on international flights were required to have the change made before departing Australia. Read the full story of aircraft registration markings in Australia here.