To: lomapaseo
Technically, you are correct. AC-25-1309 states the following: Between 10 7 to 10 9 fleet flight hours you can incur serious injury to or death of a relatively small proportion of the occupants as well as reduction of the aircraft capability or of the crew ability to cope with adverse operating conditions.
From 10 9 and beyond it states; Prevention of continued safe flight of the aircraft to include loss of the aircraft and / or fatalities meaning, more than a relatively small proportion of the occupants.
However there is one problem. 1309 addresses the aircraft and it alludes to 10 9 applying to the aircraft. In actuality 10 9th applies to a system problem that can escalate upwards and cause loss of the aircraft. In my previous post I mentioned the use of Boolean algebra to determine the safety of a system going all the way up to 10 17th which is proved through the manipulation of reliability numbers that were derived from non representational data bases and massaged with K factors. In other words GIGO (Garbage in garbage out). If you applied the same logic to determining the safety of a large aircraft that may have as many as 30-35 systems that if they were to suffer a catastrophic failure it can be shown that at the aircraft level the safety is somewhere between 10 7 to 10 8 so now the aircraft potential for catastrophic failure is well below what 1309 requires yet the FAA does nothing about it.
