The letter, announced by Australian Minister for Defense Stephen Smith, formally asks cost and availability information.
Smith said a sixth C-17A Globemaster III, which would be obtained through the U.S. Foreign Military Sales program, would give the government increased options to support a wider range of contingencies that might require heavy-lift aircraft and also double the number of C-17A aircraft available for operations at any one time.
The acquisition of the fifth C-17A was announced by the government on March 1and Smith took delivery of the aircraft at Boeing's production facility near Los Angeles this month.
The C-17A can transport very large and heavy cargoes over long distances, providing a significant contribution to Australia's ability to reach and respond to events. One C-17A can carry up to four C-130 Hercules loads in a single lift and cover twice the distance in three-quarters of the time.
Following receipt of cost and availability information from the United States, the government will make a decision about the purchase based on capability, cost and schedule assessments.