Boeing assessed that the likelihood of occurrence of cell venting would be about one in ten million flight hours.”
Aaarrrggh...everything the FAA does requires a statistical probably of 10
-9 RELATED to itself, or the system.
Cell venting is a DEPENDENT variable, not independent, so the relationship is based on the CUMULATION of ALL events related to the battery, takeoff/landing, startup, charging/discharging, BMS, etc.
The issue is not 1 in 10 million flight hours, but a statistical relationship of all of the related events, and that the statistical average of ALL of the events to happen at the same time is 10 to the minus 9.
Of course, just so you are aware, your aircraft has a 10
-9 capability to stay within the selected RNP level...
edit..and really, quoting Gates???..