bombinha
I have never worked for Boeing but I do know from friends that they went into design overload after the Lauda Air incident to redesign the reverser systems.
I'm surprised the PW4000 reverser was certified for in-flight deployment in the first place - may be an ex Boeing person could clue us in on this.
I agree on the "no perfect system" since the only truely safe aircraft is the one that never flies (even then you could trip over the landing gear I suppose
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The science is to produce a system that has a probability of inadvertant deployment so low as to be acceptable to our good friends at the FAA.
Going back to certification by controllability, the TR has proven by testing and/or analysis that it is structurally adequate during deployment at certain prescribed airspeeds and power settings, maybe the Lauda Air TR was certified using system redundancy - that is pure speculation on my part.
I've been away from reversers for a while but the probability numbers (for inadvertant deployment) generated by the system Failure Modes and Effect Analysis (FMEA) need to be extremely small.
I guess what I am rambling on about is that we endeavor to reduce/mitigate the risk to an acceptable level....by definition it cannot be eliminated.
Apologies for any spelling errors - I'm asn engineer, we are not supposed to be able to spell
