Originally Posted by
Lonewolf_50
As I read through tdracer's post (quoted by punkalover) and then your post AAKEE, I will observe that 'catastrophic' for the FAA cite you made is within the context of airworthiness, while a hull loss might be seen as 'catastrophic' (despite nobody being hurt in that incident) by the bean counters.
I thought I wouldn’t need to bore thread followers with all the regulation text,
but, this is the appropriate text from the Advisory Circular (
AC ):
7.2.2.3.2 Nevertheless, some failures within airplane systems common to multiple engines may cause a catastrophic multiple engine thrust loss. These should be assessed by the applicant to ensure that they meet the “no singlefailure” and “extremely improbable” criteria of §§ 25.901(c) and 25.1309(b), as well as the engine-to-engine isolation criteria of § 25.903(b). Systems to be considered include, but are not limited to:
From how I read this, and how the basical principle for certification according to FAR/CS25 and 29 you should not be able to certify a system that from a single failure ends up in a catastropic failure.
The designer needs to make a System Safety Assessment and would need to find that the single sensor could end up with both engines lost in flight. Which could not be accepted of course.