Section 450.143 - Safety-critical system design, test, and documentation(a)Applicability. This section applies to all safety-critical systems, except for- (1) Highly reliable flight safety systems covered under § 450.145 ; or(2) Safety-critical systems for which an operator demonstrates through its flight hazard analysis that the likelihood of any hazardous condition specifically associated with the system that may cause death or serious injury to the public is extremely remote, pursuant to § 450.109(b)(3) .(b)Design. An operator must design safety-critical systems such that no credible fault can lead to increased risk to the public beyond nominal safety-critical system operation.(c)Qualification testing of design. An operator must functionally demonstrate the design of the vehicle's safety-critical systems at conditions beyond its predicted operating environments. The operator must select environmental test levels that ensure the design is sufficiently stressed to demonstrate that system performance is not degraded due to design tolerances, manufacturing variances, or uncertainties in the environment.(d)Acceptance of hardware. An operator must-(1) Functionally demonstrate any safety-critical system, while exposed to its predicted operating environments with margin, is free of defects, free of integration and workmanship errors, and ready for operational use; or(2) Combine in-process controls and a quality assurance process to ensure functional capability of any safety-critical system during its service life.(e)Lifecycle of safety-critical systems.(1) The predicted operating environments must be based on conditions predicted to be encountered in all phases of flight, recovery, and transportation.(2) An operator must monitor the flight environments experienced by safety-critical system components to the extent necessary to-(i) Validate the predicted operating environments; and(ii) Assess the actual component life remaining or adjust any inspection period.(f)Application requirements. An applicant must submit to the FAA the following as part of its application:(1) A list and description of each safety-critical system;(2) Drawings and schematics for each safety-critical system;(3) A summary of the analysis to determine the predicted operating environments and duration to be applied to qualification and acceptance testing covering the service life of any safety-critical system;(4) A description of any method used to validate the predicted operating environments;(5) A description of any instrumentation or inspection processes to monitor aging of any safety-critical system;(6) The criteria and procedures for disposal or refurbishment for service life extension of safety-critical system components; and(7) A description of the standards used in all phases of the lifecycle of each safety-critical system.