He returned to Port Adelaide and played for them in the 1939 and 1940 seasons.
North Melbourne
He sustained serious head injuries in a car crash, in Adelaide, on Saturday night, 26 September 1940 — which explains the remarks made about Brock's first appearance for North Melbourne, against Hawthorn, on 5 July 1941: "Recently injured, played with one side of his head plastered", and " was playing at a disadvantage through a recent head injury". Following his enlistment in the RAAF on 6 January 1941, and his subsequent relocation to the RAAF Flying Training School in Victoria, Brock was granted a permit to play with North Melbourne in the Victorian Football League on Saturday morning, 5 July 1941. He played in his first match for North Melbourne that afternoon; and then played on each of the next three Saturdays.
Death
He was killed in an aircraft accident near the You Yangs, on 2 August 1941, during a RAAF training exercise in World War II, when two training aircraft, flying in formation, collided with one another. Brock had been chosen to play for North Melbourne against Richmond on Saturday 2 August 1941. However, because he was unable to get leave from the RAAF, he had to withdraw from the team at the last minute -- and he died on that very morning.
Coroner's inquest
At the coroner's inquest, conducted by Mr Tingate, P.M. on 19 August 1941, evidence was given that the conditions on the day were far from satisfactory -- very gusty and, as a consequence, there were many air pockets -- and that Brock was a passenger in one of three aircraft flying in a V formation. At one stage of the training exercise, the trainee pilot of Brock's aircraft "signalled to the other pilots to change positions in the V formation, and the plane on the left of the V dropped underneath to take up a new position". Brock's plane hit an air pocket, the pilot "felt a bump, and his plane dropped on to the one beneath" — " controls failed to respond, and the machine spun down out of control". The trainee pilot of the other aircraft lost control of his craft immediately the planes collided; and both he and his passenger, John Distin Hill, successfully bailed out. However, despite being instructed to bail out by the pilot McGuire his passenger Brock did not jump -- McGuire stated that "Brock must have felt the crash and known what happened, but still did not jump".
Coroner's verdict
The coroner's finding was one of accidental death.
Funeral
His funeral was held on Monday, 4 August 1941, at the Springvale Crematorium. His remains were cremated.
