The Dornier company was given financial assistance from the German government to develop a larger STOL transport to carry up to 13 passengers.
The type was designated the Do 28D and later named Skyservant.
The Do 28D was a complete redesign and shared only the basic layout and wing construction of the earlier versions.
The fuselage and engine nacelles were rectangular, unlike the rounded Do 28A/B. The aim was to develop a simple and rugged aircraft for use under arduous conditions, which could be easily maintained.
With a crew of two pilots, the cabin accommodated up to 12 passengers; freight could be loaded easily through large double doors and with the seats removed the cabin gave 283 sq ft (26.3 m²) of unobstructed space.
The first flight of a Do 28D took place on 23 February 1966 and the type was publicly exhibited at the Paris Air Show at Le Bourget airport in June 1967.

A further variant of the Skyservant was the Do 28D-2/OU (Oil Unit).
Two aircraft were fitted with radar and SLAR (Side-Looking Airborne Radar) to monitor oil pollution in the Baltic and North Seas.
Painted in a white scheme, they were operated between 1984 and 1995 by MFG 5 of the Marineflieger, on behalf of the German Transport Ministry.
These aircraft are easily recognised by the fuselage-mounted SLAR antenna and a radome under the cockpit.
In 1991, both aircraft operated for several weeks in the Persian Gulf during the Gulf War under the control of the United Nations.
These two aircraft were replaced by the Do 228 at the end of 1995.
These Skyservants are preserved in the Aeronauticum museum at Nordholz.

In 1997, the Hungarian engineer A. Gál developed a conversion based on a D-variant, that was intended to meet the requirements of skydivers.
Instead of the Lycoming piston engines, Gál had two Walter M601-D2 and now its derivative General Electric H75 turboprop, modified three-blade AVIA propellers and a skydiving kit installed by Aerotech Slovakia on seven planes.
Although CAA, Hungary's aviation authorities, instantly certified the conversion, the JAA-certification could not be applied for before 2007, due to certification restrictions on the engines.
In 2008, there have been six planes flying in Europe, all of them Hungarian registered, mainly at dropzones in Soest, Germany, Target Skysports, Hibaldstow in the United Kingdom, Algarve (Portugal) and Seville (Spain).
The Dornier company was given financial assistance from the German government to develop a larger STOL transport to carry up to 13 passengers. The type was designated the Do 28D and later named Skyservant. The Do 28D was a complete redesign and shared only the basic layout and wing construction of the earlier versions. The fuselage and engine nacelles were rectangular, unlike the rounded Do 28A/B. The aim was to develop a simple and rugged aircraft for use under arduous conditions, which could be easily maintained. With a crew of two pilots, the cabin accommodated up to 12 passengers; freight could be loaded easily through large double doors and with the seats removed the cabin gave 283 sq ft (26.3 m²) of unobstructed space. The first flight of a Do 28D took place on 23 February 1966 and the type was publicly exhibited at the Paris Air Show at Le Bourget airport in June 1967. 
A further variant of the Skyservant was the Do 28D-2/OU (Oil Unit). Two aircraft were fitted with radar and SLAR (Side-Looking Airborne Radar) to monitor oil pollution in the Baltic and North Seas. Painted in a white scheme, they were operated between 1984 and 1995 by MFG 5 of the Marineflieger, on behalf of the German Transport Ministry. These aircraft are easily recognised by the fuselage-mounted SLAR antenna and a radome under the cockpit. In 1991, both aircraft operated for several weeks in the Persian Gulf during the Gulf War under the control of the United Nations. These two aircraft were replaced by the Do 228 at the end of 1995. These Skyservants are preserved in the Aeronauticum museum at Nordholz.
In 1997, the Hungarian engineer A. Gál developed a conversion based on a D-variant, that was intended to meet the requirements of skydivers. Instead of the Lycoming piston engines, Gál had two Walter M601-D2 and now its derivative General Electric H75 turboprop, modified three-blade AVIA propellers and a skydiving kit installed by Aerotech Slovakia on seven planes. Although CAA, Hungary's aviation authorities, instantly certified the conversion, the JAA-certification could not be applied for before 2007, due to certification restrictions on the engines. In 2008, there have been six planes flying in Europe, all of them Hungarian registered, mainly at dropzones in Soest, Germany, Target Skysports, Hibaldstow in the United Kingdom, Algarve (Portugal) and Seville (Spain).
Dornier Do 28