The Beginning of The Long Road to 18 ops.
After attempting to join the RCAF while under the age of 18, Brenner enrolled in the University of British Columbia taking a course in Chemistry . While there he enrolled in the Canadian Officers Training Corp.

By March of 1942 he was now able to join the RCAF. After his training at Manning Depot No. 3 at Edmonton. His request for Pilot or Observer training was evaluated at No.7 Initial Training School in Saskatoon. It is here that the recruits are evaluated for the different aircrew Trades. From their selection procedure, Bremner was selected for Observer training.
The Observer trade was later replaced by Navigator and Bomb Aimer designations. In the case of John Bremner he did his training and received his Observer brevet. For all of 1942 he continued his training, Once the Selection Committee had him down as Observer he was posted to No. 2 Air Observer school in Edmonton.

By December of 1942 he was ready for an overseas posting. Leaving RCAF "Y" Depot in Halifax and arriving at No. 3 Bournemouth where all RCAF personnel were posted prior to assignment. In Bremner's case a further course in Observer training took place in Staffordshire at No. 3 Observer Advanced Flying Unit.

His next posting was to No. 24 Operational Training Unit at Huntington. It would be here where he became part of the Roderick McIvor crew. He joined five other men all new to each other and worked at forming a well oiled machine. There then men would spent almost 3 months flying together and getting to know the ways of Bomber Command.
After a few days leave he and the others were posted to No. 1659 Heavy Conversion Unit. This would be the step towards being posted to a squadron which would be flying four engine bombers. For many the first look at their Halifax would leave them in awe. The larger and more powerful "heavy" bombers also needed a certain amount of training.
For the next two months the McIvor crew now with its seventh member Sgt. Stanley Rigden as Flight Engineer they began to get to know the quirks of the Halifax.

By December of 1943 after almost a year of being together, training together they would join 419 Squadron. Their first sortie gave them a taste of what was to come.