SAFETY CRITERIA FOR FAIL-OPERATIONAL AUTOLAND SYSTEMS AND THEIR APPLICATION

The airworthiness requirements for the certification of automatic landing systems in civil aircraft include an explicit statement of the safety level to be achieved. For compliance with these requirements a safety assessment of the system must be made, and accepted by the airworthiness authority. It must contain a logical analysis which identifies all critical failure conditions of the system and shows that the probability of each is appropriate to the degree of hazard associated with it. It should also examine the factors which influence the performance of the system and show by means of analysis, simulation, and flight testing that the safety level will be acceptable. The analysis will establish the maintenance checks necessary together with their frequency, and any other limitations on the use of the system.