On Feb 24, 4:10 pm, Bob Noel
wrote:
In article ,
No. Cost is not part of the equation wrt reducing risk, at least as far
as the FAA is concerned. If you were an applicant and tried to get
an aircraft certified that didn't meet the standards in AC 23.1309 or
AC 25.1309 because it would cost too much, the FAA would deny
the application.

I see what you're getting at. Those ACs indeed specify a maximum
acceptable probability for e.g. a catastrophic failure, regardless of
the cost of keeping the probability within that bound. But that's
still consistent with my point about cost, for three reasons.

First, the decision where to set the acceptability threshold is
already informed by the FAA's knowledge of what threshold is
affordable. The ACs' acceptable probability of catastrophic failure,
especially for the less expensive classes of GA aircraft, is high
enough to allow many fatalities per year across the fleet. If much
higher safety were achievable at a reasonable cost, the FAA would
presumably have set the probability threshold lower.

Second, for the more expensive classes of GA aircraft, that threshold
IS set lower, by two or three orders of magnitude! Presumably, that's
in part because the bigger planes can afford to meet higher safety
standards--standards that would swamp the cost of the smaller planes.

Third, those ACs set a CEILING for acceptable failure probabilities.
Unless I've missed something, there's nothing in the ACs to prevent
the FAA from deciding that a particular item of safety equipment is
required for airworthiness, even if the absence of that equipment
would still leave the catastrophe probabilities within the standards
set by the ACs. And cost is surely a factor in making THOSE decisions.
(For example, if ADS-B technology cost $500,000 per plane, the FAA
would not be proposing to require it.)