The Dornier Do 28 Skyservant is a twin-engine STOL utility aircraft, manufactured by Dornier Flugzeugbau GmbH. It served with the Luftwaffe and Marineflieger and other air forces around the world in the communications and utility role.
The Do 28 was developed from the single-engine Do 27 at the end of the 1950s. The design shared the high-wing cantilever layout and the lift augmentation devices of the Do 27, together with the rear fuselage which seated six passengers. - http://en.wikipedia.org/wiki/Dornier_Do_28
Dornier Do28 Skyservant G-ASUR based at Old Warden during this sound recording.