On the 14 March 1950 a number of Royal Air Force, Avro Lincoln's from No. 230 Operational Conversion Unit RAF took off from RAF Scampton bound for RAF Hemswel, England on an night time cross country exercises. In the early hours of the 15 March a controller at RAF Barton Hall instructed three of the Lincoln's to divert to RAF Valley, Anglesey, Wales due to bad weather at RAF Scampton. It was at 2:55am GMT that one of the Avro Lincoln's (RF511) had gone missing & the other two aircraft landed safely Five minutes later. The wreckage of RF511 was found at 5:20 GMT on Carnedd Llewelyn & confirmed all Six crew had died. The subsequent Court of Inquiry determined that the likely cause of the crash was the pilot error. The crew had turned onto a southeasterly course over Anglesey instead of the reciprocal out to sea. The pilot misheard the instruction to turn 180 degrees as turn 80 degrees resulting in a Controlled flight into terrain.