Tandemrotor. .. .I was familiar with the BOI, but not with the Crew strengths of the Detatchment as they did not form part of the BOI.. .. .Your explanation is, however, very interesting.. .. .The BOI seem to have been in no doubt that the Flight Planning for the fatal sortie had been done by Flt Lt T. Just one reference, out of several, will suffice:- para 67c “ as Flt Lt T had carried out the flight planning for the sortie, including calculating the Safety Altitude for each leg, he would have been familiar with the intended route.” The BOI came to their conclusion on the basis of the evidence given to them during their investigation.. .. .At the FAI it appears that Lt K gave evidence that HE had carried out the Flight Planning for the sortie. Certainly the photocopy of the chart left behind showed that the writing of the person who prepared it did NOT correspond with the handwriting of eiher Pilot on the fatal flight. Some have suggested that the copy of the chart left behind was only an illustration and not a definitive statement of their Flight Plan. I would say “why leave a photocopy and not the chart”?. .. .The next question is, if as it appears from the evidence given to the FAI, the other crew did the Flight Planning; why did the RN exchange Pilot do it instead of the Navigator? . .. .The final question is how did the BOI, on the basis of the sworn evidence given to it, reach the conclusion that Flt Lt T had planned the sortie the previous evening?