This changes everything.
If the pilot had a similar level of carboxyhaemoglobin to Emiliano , which seems certain , then he'd probably have passed out at the controls or at least been unable to co ordinate his movements. Thus, all the other factors become superfluous to the actual cause of the accident, and are relegated to free standing potential criminal offences and health and safety infringements.

In the absence of toxicology for the pilot, it cannot be absolutely proven though, and so I'd anticipate an open verdict at the inquest.

The legal argument now will be between the alternatives of poor maintainance and some " act of God" such as a rupture in an exhaust system which couldn't have been anticipated. It doesn't make a finding of some liability on the part of the club impossible , but it makes that less likely.