Now that we are pondering over dctyke's 2nd post re in situ removal of the shackle bolt, I thought it might help if we remind ourselves of what he said first time round (sorry dct, pennies are at last beginning to drop) :-
In 1991 that seat would have been serviced every 12 months. If the crack testing was being done then it would have been in the seat bay. The shackle bolt would never have been fitted/removed/fitted in-situ as it is done now. Even in 1999 this was the case. Sometime after that a decision was made to extend seat servicing to two, then three years. Someone devised the new proceedure of removing the shackle bolt in-situ to accomodate crack testing as it's phase was shorter than the extended seat bay servicing times.
So for most of its life this seat was removed from the aircraft to be serviced in the station seat bay once a year. Then the savings at the expense of we know what kick in, and it stays in the aircraft for two years, then three years, then it is taken to some far away centralised servicing depot.
In the meantime it becomes necessary to perform testing for beam cracks at more frequent intervals, ie while the seat is in the aircraft. Can't be done because the shackle is in the way and the scissor shackle can't be opened to release it. So undo the bolt and remove it that way, carry out the test and then replace the shackle and do up the bolt. Simples! Only trouble is MB didn't design it for that procedure. So what I would like to know is what is the process required to ensure that the new procedure is safe, before it is cleared to be carried out on the line?