You should have put a section in your safety management plan that said something like this:
When we do a safety investigation we have an action item to develop a plan to forward to the Manager about when we plan to have the investigation report to the Manager, and we assume that plan would be done in the next couple of months. We would be hopeful that it would not be long after that most of the draft investigation report would be delivered to the Manager. For the purposes of this section, “not long after” means at least 13 years.
If it’s good enough for an erstwhile DAS to say that about the regulatory ‘reform’ program in 2005, it’s good enough for an air operator’s SMP.