Australia has signed an agreement to acquire a fifth C-17 strategic transport, with Boeing to deliver the aircraft in just four months' time.
Announcing details of the new Foreign Military Sales deal on 18 April, the US manufacturer said: "Due to the Royal Australian Air Force's immediate need for an additional airlifter, the US Air Force has approved Australia's request to take delivery of its fifth C-17 in August."
To be operated by the RAAF's 36 Sqn from Amberley air base, Queensland, the aircraft will join four others that entered use between 2006 and 2008. Its addition will allow the service to meet "an increased demand for humanitarian and disaster relief missions", Boeing says.
The RAAF has recently used its C-17s to support humanitarian relief operations following natural disasters that have devastated parts of Australia, Japan and New Zealand.
© Australian Department of Defence
Australian C-17s delivered relief supplies to Japan following last month's earthquake and tsunami
Plans to acquire the new aircraft were outlined by Australian minister of defence Stephen Smith at the Avalon air show earlier this year, when he revealed that Canberra had requested pricing and availability data from the US government.
In a 9 March notification to Congress, the US Defense Security Cooperation Agency valued the sale at an estimated $300 million, including associated equipment, spare parts, training and logistical support.
Australia's decision to buy a fifth C-17 is expected to mean that it will not exercise an option to acquire two more Lockheed Martin C-130J tactical transports to expand the RAAF's current 12-strong fleet.
Boeing has so far delivered 230 C-17s, including 210 to the USAF. The type is also operated by Canada, Qatar, the United Arab Emirates and the UK, and by a 12-member group of NATO and Partnership for Peace nations.