RE: Hyperveloce (#3971)
(How is the "acceptable relation" between 1)-2) & 3)-4) & the overall flight safety impact defined or evaluated ?).
How it's done? Read Appendix A in this document (see for example page 86):
NTSB safety report no. SR-06/02
Safety Report on the Treatment of Safety-Critical Systems in Transport Airplanes
http://www.ntsb.gov/publictn/2006/SR0602.pdf
(Link originally provided by SPA83 in his post #3841 on page 193 (23-07-09), thank you SPA83)
Two quotes from the "Executive Summary":
The Safety Board recognizes that the findings in this report are presented during one of the safest periods in commercial aviation history and acknowledges that FAA’s certification process has contributed significantly to that level of safety. However, the Board notes that there is room for improvement. The report includes three recommendations in two areas.
The second area focuses on the ongoing assessment of safety-critical systems throughout the life of the airplane. The Board concluded that a program must be in place, once the type certification process is completed, to ensure the ongoing assessment of risks to safety-critical systems. Such a program must recognize that ongoing decisions about design, operations, maintenance, and continued airworthiness must be done in light of operational data, service history, lessons learned, and new knowledge, for designs that are derivatives of previously certificated airplanes.
regards,
HN39