The potential to catch fire must still be one in one BILLION flight hours,
again...aaaarrrgggh!
Per FAA AC23-1309 SYSTEM SAFETY ANALYSIS AND ASSESSMENT FOR
PART 23 AIRPLANES
Step 1: Determination of the "average flight;"
Step 2: Calculation of the probability of a failure condition for a certain "average flight;"
Step 3: Calculation of the "average probability per flight" of a failure condition; and
Step 4: Calculation of the "
average probability per flight hour" of a failure condition.
The failure mode must be statistically 10
-9 (1 in a billion) for
EACH FLIGHT HOUR.