That is a very sound suggestion.
23 years ago I lost my licence after suffering what was initially diagnosed In hospital as a TIA, although the immediate thoughts of my wife, a nurse, and my sister, a doctor, was that I had suffered a mini stroke.,
In fact, after extensive diagnoses it was ascribed to Transient Global Amnesia, part of my brain, the left temporal lobe dealing with memory, had simply shut down. I woke up, became normally aware, in hospital about 12 hours after the onset having no recollection of the hours between onset but full memory of all before that. Although CAA removed my licence, an ATPL as I was a 75/76 captain at the time, as the risk of recurrence was considered unacceptable, I was eventually granted a PPL and gliding instructor’s certificate. Little is known about TGA because it us a rare occurrence and not considered life threatening unless you are a pilot, surgeon or train driver, I was told by my distinguished neurologist !
So, based on personal experience I would suggest TIA or TGA, (was anyone in the AAIB even aware of its existence ?) and about which I learned a lot is far more likely, in my opinion based on that experience, than cognitive impairment, something I never heard of in my entire flying career.
Perhaps the fact that little is known or understood about TGA is one reason its possibility was not raised in the investigation. I dont think the possibility could be discounted., but the likely remaining evidence of TGA can be a slightly abnormal EEG trace.
Last edited by RetiredBA/BY; 7th Jul 2020 at 20:19.