11/30/2011. Remarks by Johan Visschedijk: "This STOL-aircraft was originally built in April 1975 as a Do 28 D-2 fitted with two 380 hp Lycoming IGSO-540A1E engines.

In 1976 conversion to turboprop started and on April 9, 1978 D-IBUF was flown powered by two 600 shp Avo Lycoming LTP 101-600A turboprops. It was designated Do 28 D-5X Turbo-Skyservant, however, the production version was designated Do 28 D-6, powered by two 400 shp Pratt & Whitney Aircraft of Canada PT6A-110 turboprops.

In 1980 Dornier redesignated the piston-powered Do 28 D-2 to 128-2 and the turbine-powered Do 28 D-6 to 128-6 respectively. Eventually D-IBUF was also fitted with the PT6A turboprops as seen above, and redesignated 128-6.