The following notes are based on an article by Eric Mayall written in 1993 and published in the Air Crew Association magazine.

With the formal establishment of the Flight Engineer as a separate aircrew category, it required a clear definition of both the responsiblities and the training required to perform them. These were enshrined in Air Ministry order A978/42 dated 15 August 1942 and were as follows:

1. To operate certain controls at the Engineer's station and watch appropriate gauges as indicated in the relevant Air Publications.

2. To act as Pilot's Assistant

3. To advise the captain of the aircraft as to the functioning of the engines and repairs during flight, the fuel, oil and cooling systems.

4. To ensure effective liaison between the captain of the aircraft and the maintenance staff, by communicating to the latter such technical notes regarding the performance and maintenance of the aircraft in flight as may be required.

5. To carry out practical emergency repairs during flight.

6. To act as stand-by Gunner.

Selected candidates will be required to undergo the following training:

1. The Junior NCO course, if appropriate.

2. A course of approximately five weeks an Initial Training Centre

3. A three-week course of Air Gunnery training.

4. A course of technical instruction, which may include a course at the manufacturer's works.

This Air Ministry order also covered the question of Rank and Commissioning. To ensure that all aircrew received reasonable treatment from the enemy should they fall into their hands as prisoners-of-war, a minimum aircrew rank of Sergeant had been established.

A contract for the construction of an RAF Station at St Athan in Glamorgan, Wales, was signed in 1937 and work commenced immediately. The first party of airmen arrived at the camp on 1 September 1938: The initial unit to be based there was No. 4 School of Technical Training (SoTT) which was tasked with the training of Flight Mechanics and Riggers as well as Drivers.

The station was mobilised for war on 2 September 1939, the first course at St Athan commenced on 30 May 1942, and comprised 60 trainees following a syllabus which had only been drawn up in April. The initial two courses were of 3 weeks duration, the following two of 4 and 5 weeks duration and the fifth and subsequent courses took 6 weeks - the planned length. The number of personnel planned for each course was 100, but fluctuated from time to time. Some delays occurred in the Complementary Gunner School Courses, but this requirement was dropped in mid-1943 and progress improved thereafter.

On arrival at St Athan, the current requirements for individual aircraft types were assessed and the course was split accordingly, with training following on that specific type alone although some general tuition was also given.

Air Ministry Order A707/42 dated 16 July 1942 allowed direct entrants to be trained as Flight Engineers . Obviously additional training would be required for those entrants and so a longer course of 24 weeks was established in 1943, when the full impact of Direct Entrant recruitment was felt. This led at times to an output of over 500 men in one week and a total population at No. 4 SoTT of over 5,000!  This level of output was principally aimed at replacing the very heavy aircrew losses of Bomber Command.

By the end of the war over 25,000 Flight Engineers had graduated from the School, these men had seen active duty on every front.