Walter
You are referring to the crash of Sunderland Mk3 W4026. There was a survivor (Sgt Jack the rear gunner) who gave evidence to the Inquiry and you have also failed to mention that the Navigator was not the normal Navigator for this crew - indeed he was not even from the same Squadron. He came from 423 Sqn RCAF.
So please tell us - what exactly was the new piece of navigational equipment that was used to induce that particular crash?
That crash happened during a war for survival when training time was limited and casualties were high - from first to last the RAF lost 70,253 Officers, NCO's and Airmen killed or missing on Operations of whom 55,573 were aircrew. Bomber Command alone lost 8305 Aircrew on non operational flights.