Originally Posted by
Bell_ringer
Thats daft since part 91 is a big contributor to accidents in robboland.
It has been mandatory for some time in most civilised parts of the world
The FAA get a lot right but they seem determined to get a lot wrong.
Actually,
no service bulletin is "mandatory" unless there is an accompanying AD - that's not just for Part 91.
Problem is, before they can issue an AD, by law, the FAA needs a cost/benefit analysis to show that the benefit outweighs the cost. That's always tricky for crashworthiness changes since they only come into play
after the aircraft has already crashed - makes it's hard to define lives saved. It's much easier for airworthiness changes since you can say it'll prevent a crash (note that this isn't the case for new regulations as they only apply to new certifications - not retrofit - no cost/benefit required).