The Air Line Pilots Assoc. (ALPA) submission to the NTSB docket on the Alaska Flight 261 crash case is at
this link. (a 750kb pdf file). It provides ample grist to support the case for retro-fit of a Fail-Safe Jackscrew. I would add a few thoughts:
The airplane is supposed to be certified against catastrophic failure, and the standard is to a probability of not more than 1 in a billion flights (1X10-9, or "extremely improbable"). If one is designing a system where maintenance is the failsafe mechanism, then we are in the realm of human error, which occurs more often than a rate of once every billion. Now we are talking "improbable" error rates in the range of one in a million 1X10-6) to once in 100 million (1x10-8). So timely and proper maintenance is not failsafe, since it can fail to be properly performed at orders of magnitude 1-3 times more often than the one in a billion standard.
As this document shows, the probability of failure was virtually one, since the work wasn't done. Given the potential for human failings, I believe one could credibly argue that any flight-critical system dependent on maintenance for safety is not failsafe - by definition.
You will note in this document that the FAA had no mechanism in place to track premature wear rates. Moreover, the FAA was a silent partner in the evolution of MSG-2 to MSG-3 maintenance protocols, by which inspection intervals were lengthened (and on the basis of virtually no in-service data; so much for "data-driven" safety). Note the artful wording
-- the FAA never "approved" the MSG-3 work. Rather, the FAA
acknowledged the revised practices -- which is to say it did not assume
responsibility and thereby seems to have neatly side-stepped the issue of being held
accountable for the revised MSG-3 practices.
You will find more in this well-crafted document. If anyone wished to contest the FAA position on the Failsafe Jackscrew, it would be worthwhile first to try and establish the FAA's actual position (i.e. write to John Hickey at TAD and ask - or go FOIA). The counter-arguments Mr. Hickey has made, the position he appears to be taking on behalf of the FAA is logically indefensible, and it might serve to point out publicly just what the inconsistencies are. We shall set aside for the moment the moral and ethical escapism suggested by the material contained in the ALPA analysis.