Before an aircraft is given its Certificate of Airworthiness the aircraft constructor has to satisfy the Air Registration Board that the standards laid down in the British Civil Airworthiness Requirements (B.C.A.R.s) have been met. However, if you go to B.C.A.R. and try and find something under Instrument Approach Criteria, you will be unlucky. This is because the requirements for low weather minima and blind landing operations are still in the form of A.R.B. Technical Notes and working drafts. This state of affairs has come about because of A.R.B.'s reluctance to become bureaucratic and devise arbitrary rules and regulations concerning an operation as new as automatic landing.