The D.H. 60 Moth has been described as one of the "most popular, successful and historically important types designed by de Haviland". The Moth appeared in many variants and it is sometimes difficult to identify which variant the writers are discussing. The prototype, first flown in February 1925, was powered by a 60 H.P.Cirrus 1 engine which was, in fact, half of a 120 H.P. Airdisco engine on a new crankcase and weighing only 290 lbs. The success of this model led to further developments. In 1926 the engine was upgraded to an 85 H.P. Cirrus 11 and shortly after the wingspan was increased by one foot. This model became known as the D.H.60X or the Cirrus II Moth. Within a short time the Moth had broken records and the orders flowed in from the R.A.F, Canada, Finland, Argentina, Sweden Germany, U.S.A., Italy, New Zealand, Singapore, Spain, South Africa and India. In 1928 a new variant was introduced with more power - a Cirrus III, 90 H.P. - and a split axle landing gear. The weight of the plane had increased and more power was indicated which led de Haviland to develop the 100 H.P. Gipsy engine. The newly equipped Moth was designated the D.H.60G but quickly became known world wide as the Gipsy Moth. In 1928 the redoubtable Gipsy had broken records for altitude, endurance, speed and maintenance free operation. It became the favourite of long distance fliers, both men and women.
In the development of the Moth an event occurred in November 1926 of particular relevance to Canada when H. S. Broad flew the first float equipped Moth from the Medway near Rochester. It was fitted with all metal twin floats, which had originally been fitted to a Short Mussel G-EBMJ.
As the Moth was being developed the HS-2L flying boats, which had given bush flying its wings, were showing their age. The rigours of bush flying, the fragility of the aircraft and the unreliability of the engines meant frequent interrupted flights and costly overhauls.
The first Moth to arrive in Canada was G-CAHK "The Spirit of the Valley of the Moon" on board the icebreaker Stanley operated by the Department of Marine Fisheries. The vessel left Halifax for a survey of Hudson Strait and arrived at Wakeham Bay August 22, 1927. On five occasions the plane crewed by Squadron Leader Lawrence and F/LT Leitch, was lowered over the side to survey four different areas of the Strait. Unfortunately the captain of the Stanley would not allow the plane to remain on board and it was destroyed in a storm while moored near shore.
Generally it was determined that the wood and fabric construction of the original Moth was unsuitable for Canadian flying conditions leading de Haviland to develop the D.H.60M with a welded metal steel tube fuselage, wide cockpit doors and a large locker and distinguishable due to its prominent longitudinal stringers. Eventually many of the G models were rebuilt as M models. The Moth introduced a rudimentary intercom system between the pilot and passenger in the form of a tube to talk into and two tubes connected to the helmets as receivers. Unless involved in mapping or forest identification flights the Moths usually did not carry observers. The ease of changeover from floats to skis meant that for the first time the OPAS was able to operate on a twelve month basis.
The first of the new 60M's - G-AAAR- arrived in Canada in 1928 and as G-CAVX was tested on wheels, skis and floats by the RCAF. Its impressive performance resulted in more orders from the Ontario Provincial Air Service and by 1932 the service had thirteen Moths on strength.