Crewing Vehicles & Certifications

[Cyber]

To fully crew a vehicle will all the occupants have to have the required certifications?

For example to crew a galaxy fully will you need 4 galaxy certified guys (1 pilot + 3 gunners) or is it simply the pilot who has to be certified...?

Same with a main battle tank or heavy buggy... would you need a certified person for each gun or would just 'any grunt who is wearing light enough armor to fit in the slot' apply as long as there was a certified driver...?

I hadn't seen anything specifically on this and was just curious if anyone knew how the addition crew positions worked as far as certifications. I think it would kinda suck to have to have 4 fully certified pilots to be able to fully man a transport...