Well by now I suspect that most readers have just learned to skip over this thread as it is probably a trifle boring to the normal PPrune.

Eyes in your backside refers to "excellent hindsight" rather than convincing forsight..

If you mean by experiencing a "far lower" failure rate, that the manufacturers were overly optomistic in their non-credible design assumptions used in the FMEA's I can agree with you in the reverser case. The problem was partly to do with lack of oversight of the many vendors' QA programs.

Regarding your comments on Service Buletins (SB) they are issued for a variety of reasons and in the case of the burner cans it was more for the rectification of shortfalls in presumed maintenance than it was to correct design defficiencies.

And as the person responsible for developing the rules by which system safety progresses forward by incorporating "lessons learned" I can tell you that time and money do not enter into the equations once the rule is promulgated.

But then again revisited.
 

To: lomapaseo

Once the lesson is learned the educational process tends to deviate. The NTSB learns the lesson from a standpoint of safety and they try to minimize or totally eliminate the possibility of the accident or incident from ever happening again by recommending to the FAA what must be done. This can take the form of a fleet grounding or a very expensive retrofit program. The FAA on the other hand learns the lesson from the point of view of the operators and as such very seldom follows the recommendations of the NTSB.

Here is how the FAA determines if an operator or operators must incorporate a necessary design change as a means of preventing a reoccurrence of the problem. The FAA will perform a cost benefit analysis to determine if it is cheaper to incorporate a fix as opposed to not incorporating that same fix. They determine the cost in human lives if that same accident were to happen again. A branch of the department of transportation the parent of the FAA makes an annual determination of what a human life is worth. This figure along with the cost to the operators related to downing their fleet, the cost of the new equipment or new system design times the number of aircraft in the fleet and the financial loss to the airline caused by the loss of their aircraft due to the grounding. If the cost of making the change is more expensive than not making the change the FAA will vote against the NTSB recommendation to make the change.

And, these are the guardians of our safety.

I see that we have made excellent progress in understanding.

We finally have a government of the people, by the people ... that we can blame this on. :)