The de Havilland Twin Otter was
designed in the mid-1960s with two turboprop engines so it could
take off and land on a very short runway.
The first Twin Otter had two, 578-horsepower Pratt & Whiney
Canada PT6A-20 turboprops each with a three-blade propeller. The
300 series changed to the more powerful Pratt & Whiney Canada
PT6A-27, each having 620-horsepower.
The Twin Otter had extraordinary lift ability and could land
on very short runways. This was possible due to the craft’s twin
engines, the ailerons working together, and the addition of the
double slotted trailing edge flaps.
The 200 series of the Twin Otter was developed in 1968, and
had an extended nose to improve performance. The 200 series also
had more storage space for luggage and cargo in the back of the
aircraft. In 1969, further improvements were made, including a
more powerful engine that increased the takeoff weight by 450
kilograms, and a larger space inside the aircraft to seat 20
The Twin Otter remained in production until 1988.