challenge: What was the conclusion of the board of inquiry regarding Captain Hartley's actions in the 1953 Nutts Corner BEA Vickers Viking accident?
  
  A. He was not found to have made any mistakes in the lead-up to the accident
  B. He was found to be entirely at fault for the accident
  C. He made 'errors of judgement' but no moral blame was attached to him
  D. He was not considered responsible for the accident due to equipment failure
  Answer: 