Leaving aside the details of your concerns with the application of administrative process and the roles of a regulator/accrediting body. I have no skin in the game or knowledge on that front, I have no CASA connection and empathise with your frustrations. It looks like you've not had a pleasant experience.
Nevertheless, you had a flight safety relevant condition which was treated using novel (i.e. new techniques) for which a significant body of long term evidence has not been generated. Your specialist opinions did not address the specific questions required in order to make a sound risk based decision. You then further complicated the process by acting as your own medical advocate with the avmed unit. Where was your DAME or GP in this process? Further complicating this you sought out 'tests' to provide secondary proof against a negative, which can't really logically ever be done i.e. "prove it won't happen"
There's an element of fixation around 12 months being 'required' to make a decision. Without diving into a large amount of academic papers, generally, any instrumentation of your brain, its vascular sctructures and the cavity it sits in has a significant risk of generating a (new) source of future seizures (i.e. risk) and causing damage/infection/bleeding. This risk is generally realised within the first 12 months if it is to occur and the corollary is that if its occurrence rate is less than once/year then it should generally be acceptable under most aviation contexts (or have mitigations applied to make it so).
There is no evidence that can be provided in the intervening time period as there is no clinical/investigatory test able to stratify the cohort- there is generally only evidence/results of higher risk i.e. a bleed/neurological symptoms/infection etc. or immediate short term 'treatment' success. That you have normal post intervention tests is reassuring you are not at a higher risk than baseline however the condition has risks of recurrence/treatment failure/complication that no test other than the passage of time exists to prove non-occurrence. A 12 month period is somewhat arbitrary but it is the objective statistical risk standard/threshold for decision making and there is some evidence for that period roughly correlating with a period of recovery healing/rehab and then physiological stabilisation (more towards the 6-12month time period). Much argument can be had over the 1% rule and its origins/assumptions but it is what is used and sets part of the standard.
The phrasing/process in the corro out of CASA, from your position, would not be compliant with admin process law or some similar position. It doesn't strike me as particularly troublesome in providing an independent opinion. Very specific hypothesis/questions/risk scenarios/assumptions need to be addressed with rigour. Provision of a supporting or dissenting opinion (with academic clinical research/analysis to support) against these is critical in coming to a reasonable decision against a risk framework (Meta-analysis, single quality study, other cohort research and then expert opinion form the hierarchy with most weighting to the former). The absence of an opinion (against not just "fit to fly today" but time based risk and long term consequences with quality research to back it up), as would appear to have occurred with your earlier reports has led to the ambiguity/lack of probabilistic statements against the risks. I would be very surprised if any reasonable person would then afford you the 'benefit of the doubt' rather than take the conservative position.
I'd likely consider you recommendable to be fit to fly Class 2 with restrictions after 12 months from your narrative but can't offer an opinion on an incomplete picture. The other question I would ask is that why not fly under an RPL or Basic Class 2 - if you VFR day fly only for your own pleasure? The emotional effort and time to 'fight' for a principle or against perceived slights is not going to be healthy for you in the long term.
Last edited by Nowluke; 6th Dec 2018 at 23:59.
Reason: Grammar error