Air Vice-Marshal Turnbull is a pilot with more than 3600 flying hours on rotary wing and fast jet aircraft. He completed his basic training in 1984 and spent the next four years flying UH-1H helicopters as a member of No. 9 Squadron which was then based at Amberley. This period included a short tour with the ANZAC Contingent of the Multinational Force and Observers based in the Sinai Desert.
Air Vice-Marshal Turnbull deployed to the Middle East in March 2007 as Chief of Staff in the Australian National Headquarters, Baghdad serving a six-month tour; followed by appointment as Officer Commanding No. 81 Wing from 01 November 2007. Following his command tour, Air Vice-Marshal Turnbull was appointed Director, Military Strategic Commitments from January 2011. He deployed to the Middle East in January 2012 completing a tour as Director, US Central Command 609th Combined Air Operations Centre where he was awarded the United States Bronze Star Medal. He returned to Australia in May 2012 to take up the dual appointments as Director General Air Command Operations (Headquarters Air Command) and Director General Air (Headquarters Joint Operations Command). Air Vice-Marshal Turnbull was appointed as the Air Commander Australia on 12 September 2014, conducting duties as the senior operational commander in Air Force. On 1 May 2017, AVM Turnbull was appointed as the Deputy Chief of Air Force.
Air Vice-Marshal Turnbull was appointed a Member of the Order of Australia (AM) for exceptional service to the ADF in air combat capability development and support to military operations in the Australia Day 2016 Honors and Awards.
Air Vice-Marshal Turnbull is married to Jackie, has four sons and one daughter.