Vice-chief of the defence force Air Marshal Mark Binskin is expected to succeed General David Hurley as Australia's next defence force boss.
In other changes set to be announced in Canberra on Friday, navy chief Vice-Admiral Ray Griggs is expected to become defence force vice-chief and current navy fleet commander Rear Admiral Tim Barrett to become chief of navy.
RAAF chief Air Marshal Geoff Brown and army chief Lieutenant General David Morrison are expected to have their terms extended, allowing them to oversee important ongoing changes including acquisition of the new F-35 joint strike fighter.
Prime Minister Tony Abbott and Defence Minister David Johnston will be in Canberra on Friday for the anticipated announcement of the new defence force leaders.
Air Marshal Binskin, 54, will return the top defence job to the air force, although he started out in the navy.
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This has led some defence insiders to jokingly refer to him as the navy's Manchurian candidate.
He joined the navy in 1978, flying Skyhawk jets. When the navy disbanded its fixed wing aviation arm, he transferred to the RAAF in 1984, flying Mirage and F/A-18 Hornet jets.
He has flown more than 3500 hours in single-seat fighter aircraft.
He rose to command the air force in 2008 and was appointed Vice Chief of the Defence Force on July 4, 2011, the same day as General Hurley.
These announcements follow another important change: Rear Admiral David Johnston will succeed Lieutenant General Ash Power as the chief of Joint Operations Command, responsible for conduct of all defence operations such as in Afghanistan.
In the past, defence chiefs have been appointed for three year terms but it's understood that will now be extended to four years, allowing those at the top more time to implement significant changes.
By appointing some new chiefs and extending the term of others, the government ends the current situation where all terms concluded on the same day - a situation that had the potential for turbulence as defence's top leadership all departed at once.
Unlike predecessor Air Chief Marshal Angus Houston, who headed defence for six years (2005-11), General Hurley's term has run for three years - like that of now Governor-General Peter Cosgrove.
It's understood General Hurley was invited to extend but opted to retire to give his successor a clear role in drafting and implementing the new Defence White Paper which will be released next year.
He plans to retire to a property on the NSW mid-north coast.
