The spy planes would boost Australia's self-defence capability and enhance the US's interests in the region, according to the US State Department.
"This sale will contribute to the foreign policy and national security of the United States by helping to improve the security of a major contributor to political stability, security and economic development in the western Pacific," the US State Department’s Defense Security Co-operation Agency said.
"Australia is an important Major non-NATO ally and partner that contributes significantly to peacekeeping and humanitarian operations around the world. It is vital to the US national interest to assist our ally in developing and maintaining a strong and ready self-defence capability."
The estimated cost for the aircraft is $US$1.3 billion.
The DSCA statement said the Australian government requested "the possible sale of up to five Gulfstream G–550 aircraft modified to integrate airborne intelligence, surveillance, reconnaissance and electronic warfare mission systems, global positioning system capability, secure communications, aircraft defensive systems; spares, including whole-life costs of airborne and ground segments; aircraft modification and integration; ground systems for data processing and crew training; ground support equipment; publications and technical data; US government and contractor engineering, technical and logistics support services; flight test and certification; and other related elements of logistical and program support".
Australia would acquire these aircraft in the early 2020s in two tranches to complement its fleet of six E-7A Wedgetail aircraft and its planned purchase of eight Poseidon P-8A surveillance planes.
The prime contractor for this acquisition would be L3 Technologies of Greenville, Texas.
L3 is a leading provider of a broad range of communication and electronic systems and products used on military, homeland security and commercial platforms. L3 is also a prime contractor in aerospace systems, security and detection systems, and pilot training.