Except for physical access, the engineer need not design maintenance into design. If you are required to spec out the equipment, which isn't always the case, then the manufacturer is on the hook for service while under warramty. A PE doesn't crawl around and service air handlers. Jeez.
Let say you want to put a 3000 CFM air handler on the roof of a factory. If the roof can't handle the load then yes the design is wrong. Maybe 2 smaller ones instead. But a PE doesn't install and maintain air handlers.
You must be a wonderful draftsman. Don’t be surprised when you’re out of a job because the computer does it better