Arfur: I can think of cost, (but is that in CAA's remit?) but who at CAA would have the experience to start with a clean sheet of paper and devise suitable rules/regs for a DA? Surely, if they have no experience they should go to those that have and consult: i.e. ask RAF what their criteria are and consider. They might be slightly more lenient, but.... What are the RAF rules and by how much does the CAA differ? Would the RAF regs be workable in a civil role?