Hello
In EASA land, a fresh aircraft weighing can only be done in an approved maintenance facility.
Can an independant part 66 mechanics update a valid WB sheet, after an aircraft modification, if the incidence on WB can be known by calculation / documented in the STC ?
“IN” or “BY” an approved maintenance facility?
At least “by” (meaning signed by), and perhaps “in”
Whatever, as it is just calculation, I wonder if we can avoid approved maintenance facility by all means.
Who is responsible for the airworthiness? You or a CAO/CAMO?
If you are, you could do it. If you know how to do it.
I am
I know how to.
Can you provide reference ?
I have this model of earlier modification, done by a Part 145 years ago.
Since this mod, a full new weighing was performed.
Now, new mods were added, and data for calculation are available
No I cannot provide a reference stating that you are allowed to do it. But I cannot find anything regarding limited pilot owner maintenance in Part-ML stating that you can’t either.
A lot of paperwork would fall under the responsibility of the airworthiness management. In this case it would be you. But maybe you should ask the person signing your next ARC, if they don’t like it you probably should let someone else do it.
Recalculating W&B for small changes in in the acceptable list of pilot-owner maintenance in AMC1 to Appendix II to Part-ML for gliders but not for aeroplane. But that is only an AMC and not the law.
In the case of the OP, I think independant Part 66 is ok. Not much reference of weighing in part ML but quite a few in part 66 on training and examination.
Fly310 wrote:
A lot of paperwork would fall under the responsibility of the airworthiness management. In this case it would be you. But maybe you should ask the person signing your next ARC, if they don’t like it you probably should let someone else do it.
Speaking from experience… 
I inquired the inspector.
I will report when I have the answer.
