Defence Aircraft Noise

Military Aircraft Engines

Commercial aircraft tend to use high-bypass, turbo-fan engines which are suitable only for subsonic flight (flying slower than the speed of sound or 1,225km/h). These engines optimise fuel efficiency and reduce noise.

Some of the RAAFs fleet are based on commercial aircraft which have been modified for military use. These include the KC-30A Multi-Role Tanker Transport (modified A330 Airbus), E-7A Wedgetail (modified 737), and KA350 King Air. These aircraft use the same type of engines used in commercial aircraft and, under normal circumstances, use commercial airline take off and landing procedures.

In contrast, military fighter jets use low-bypass, turbo-jet engines which are generally noisier than commercial aircraft engines. Most have after-burners for additional thrust and noise and can fly faster than the speed of sound (supersonic, or faster than 1,225km/h). In certain conditions, this can create a Sonic Boom. The engines need higher power-to-weight ratios for speed and manoeuvrability.

RAAFs military fighter jets include the F/A-18F Super Hornet, based at RAAF Base Amberley (QLD); the F/A-18A and F/A-18B Hornet, based at RAAF Bases Williamtown (NSW) and Tindal (NT) and the Hawk 127 based at RAAF Bases Williamtown (NSW) and Pearce (WA).

Although some training is conducted using flying simulators, nothing replaces actual experience for our pilots and crews.

Air Force reduces the effects of noise from military aircraft around airfields as much as possible. We do this by limiting the speed of aircraft; avoiding the use of after burner when safe to do so; minimising flying over residential areas and other noise sensitive buildings such as hospitals and schools; climbing to altitude as quickly as possible when departing; and, minimising flying late at night or early in the morning.