AP-3C A9-657 on approach to Darwin on 3 June 2015. Apart from some additional antennae, the most noticeable feature of this aeroplane is the lack of sonobuoy launching tubes on the underside of the fuselage immediately aft of the wing. A9-657 and the similarly configured A9-660 are expected to remain in service until 2023. Picture: Martin Porcelli