[Baron Munchausen]

A good way to avoid this mistake is to keep the components of your ship in a specific order. If you always put ship-control items first, THEN engines, THEN WEAPONS, etc... you are much less likely to 'forget' something vital. It can be a hassle to revise an old design and keep things in order, though. This is why I wish MM would return the 'replace' command to the ship design window so you can upgrade/change things without having to essentially re-assemble the entire design.