The pre-war doctrine of the Royal Netherlands Navy (RNN) was to use a combination of flying boats and submarines as an offensive weapon against an enemy fleet. As a result of this doctrine, the Naval Air Service (MLD) procured a large number of flying boats (34 Dornier Do-24K and 38 Consolidated PBY Catalina’s).
It was obvious there would be a serious need for qualified pilots and other personnel, in order to keep this large fleet operational. However, the traditional training locations in the Netherlands had been lost after the German occupation in May 1940. The Dutch government-in-exile in London decided to establish flying training facilities in the Dutch East Indies and instructed the Netherlands Purchasing Commission in the USA to buy trainers that could be delivered quickly.
The most readily available type was the Ryan ST-M (Sport Trainer-Military) a military export version of the pre-war ST-A sports aircraft powered by a 150hp Menasco C4S Pirate engine. It was a small two-seater, capable both of land and floatplane operations
The NPC ordered a total of 108 STM’s between June 20 and October 7, 1940. The STMs were built at Ryan Aeronautical Co’s works at Lindbergh Field, San Diego in southern California for delivery in Java to equip the flying schools of both the Netherlands East Indies Army (ML-KNIL) and Netherlands Naval Air Service (MLD).
The MLD order totalled 48 STMs, of which 24 were to be fitted with twin floats (and designated STM-S2), plus 12 extra sets of landplane undercarriages.
The MLD order of 48 STM’s was completed by January 1941, the planes delivered and constructed at the MLD main base at Morokrembangan, near Surabaya.
At the outbreak of the Pacific War on December 8, 1941, MLD had lost 8 Ryans in accidents, and more were lost during the Japanese advance through the NEI. There are reports of several being attacked by Japanese fighters.
By the end of January 1942 the MLD decided to evacuate its flying school plus its remaining available Ryan STMs to Australia. At least 37 dismantled Ryans were loaded on the Dutch cargo ship MS Tjinegara which left Surabaya on February 17, 1942 for Australia. The ship arrived at Adelaide on March 4 and Sydney Harbour 9 March 1942.
Pilot training was commenced at RAAF bases around Melbourne and floatplane Ryans were flown by Dutch pilots at the RAAF seaplane station Rathmines on Lake Macquarie NSW.
In April 1942 it was decided to establish the Royal Netherlands Military Flying School in Jackson, Mississippi, USA. All trainee pilots and instructors left and the MLD aircraft in Australia were handed over to the RAAF .