[foobarqux]

Thanks that document is somewhat helpful.

> FAA generally won't force you to do it a specific way.

I don't know if they "force" but practically you cannot certify commercial aircraft without adhering to DO-178 and a bunch of other standards.

So my question is what mandates or recommends use of those standards and will the same apply to UAS?

edit: Found it: http://www.faa.gov/documentLibrary/media/Advisory_Circular/A...

Turns out you are correct, using DO-178B is optional but I can't imagine anyone implementing alternative means given the complexity of DO-178.

The question that remains for me is do UASes have or will have the same or similar airworthiness requirements as other aircraft?