A guy I went to high school with went through the medical evaluation process for becoming a W01 flying helos for the Army. They found something in his eyes that would have affected his night vision 15 years out and told him couldn't fly helicopters but, they encouraged him to enlist to become a helo mechanic. He went off to FAA ATC school instead. This was around the time that Uncle Ronnie bounced the striking FAA ATCs.
When I took the FAST test they actually had a warrant officer maintenance program. It was similar to the pilot program only obviously the HS grad they took in went to learn squadron maintenance instead but still did the nine month WO school.