[ventus45]

Further to point 6.

I wonder why the ATSB did not specify the Line Number where that specific fastener was introduced, and the last Line number that it was used on. After all, Boeing would certainly know, and could have told them.

Perhaps it was all too hard.

Why ?

Possibly because there may be differences in that panel (and thus it's attachment points, and thus possibly the fasteners used) between different B-777 "models".

The production line sequence, is a mixture of different models and configurations for different airlines to meet contracted delivery schedules.

Thus, the subject fastener may not be used on all aircraft produced between Line Number X and Line Number Y. 

But putting my Logistician's hat back on (after many years) Boeing would certainly be able to say when that fastener was introduced (on Date A) and when it was last used (on Date B), and of course, which "models" it was used on. It would then be a simple matter to work out how many aircraft, indeed, which specific aircraft, were so fitted.

Obviously too hard for the ATSB though.

Then of course, look at the photos, of the marvelous condition of the "recovered" fastener, compared to the rather less than marvelous condition of the "405" fastener.

One might ask, how did the ATSB get a photograph of that fastener on the top surface of the starboard horizontal stabilizer of (405) ?


Now, that aircraft (405) was still in service in 2016. 


Where is it now ?

In any case, an examination of the Boeing B-777 Line Number Production List is interesting, might provide a clue, perhaps.

Consider Line Numbers 403, 404 and 405.

See Page 7 here, and just for fun, this.