What many contributors to this thread ignore is that when the BOI arrived at HQ1Gp for "Staffing" it already contained a finding of negligence from the Stn Cdr at RAF Odiham who stated in his remarks that Flt Lt Tapper, as the Aircraft Captain, had a Duty of Care in the conduct of the flight and that he had failed in that Duty.
My Dictionary defines negligence as " Omission of duty, especially such care for the interests of others as the law may require".
AOC 1Gp extended that verdict to include Flt Lt Cook who was the Handling Pilot.