A detailed history of the development and uses of the Otter is contained in Sean Rossiter’s recent book ‘Otter and Twin Otter’: The Universal Airplanes and I wouldn’t pretend to gainsay such an august publication. Karl Hayes has also revised his 1980’s publication which is now available on disc.

Using the same overall configuration as the highly successful de Havilland Beaver (DHC-2) the Otter actually began life described as the King Beaver; longer, with a wider wingspan and far heavier, but capable of seating up to 11, the Otter was conceived simply as a big Beaver, able to fulfil the same functions. The aircraft features the same conventional stressed skin construction and has a braced-wing with full-span slotted flaps, the outer portions acting as ailerons.

A total of 466 aircraft were built between 1951 and 1967 and utilised in over 36 countries with the military taking the bulk of orders. The US Army was the largest customer, taking delivery of 200 aircraft commencing in 1955. The Royal Canadian Air Force operated 66 Otters in both Transport and Search and Rescue roles and the aircraft fulfilled a diverse range of duties operating on floats, wheels and ski’s in locations as diverse as Antarctica and the Caribbean. The UN used a number of aircraft for a range of missions and the Otter was purchased by several overseas Governments as diverse as India, Australia, Burma, Chile and Ghana.

Civilian uses have been diverse and even today the Otter, together with its smaller but older brother the DHC-2 Beaver, remain the mainstay of many bush and more mainstream airline operations. The west coast of Canada for example hosts a number of successful Otter operators in both piston and Turbo-Otter aircraft. The airlines and operators section of this website identifies current locations and fleets. Otters were for a time an important part of fire fighting duties, carrying water in their floats, whilst at the other end of the scale, Japan Airlines commenced regular (but eventually not too successful) inter-island Otter services in the Japanese archipelago.

One of the key disadvantages of the aircraft appears to have been a degree of sensitivity with regard to overloading, especially as the Pratt and Witney R1340 piston engine was considered by pilots to be a little underpowered for the airframe. The development of the Turbo-Otter with PT-6A and Orenda powerplants revolutionised the aircraft and effectively gave it a new lease of life in commercial service. However, the development of the PZL 1000hp radial engine in Poland has also resulted in many aircraft being re-engined with a resulting increase in performance. These aircraft are now operating in areas as diverse as Peru and Alaska.