Fuselage inspection in external doubler installation

[fjcobo]

Hi all,

I’m working in the installation of a external doubler on a pressurized fuselage (for an antenna installation). I have suddenly realized today, in the installation drawing, that the doubler is covering partially four existing rivets (between stringers and skin).
So the result is that, there are four rivets which head is partially hidden by the doubler (about 50%) and not possible to do a fully visual inspection on them.

Does anybody know if this installation is acceptable and it could be enough to include these four rivets in the ultrasounds/Eddy current inspection planned for the doubler fasteners and antenna hole? (this inspection is issued from the damage tolerance analysis).

Or it should be necessary to trim the doubler flange in order to keep clear an visible the rivets heads?

Thanks in advance

 

[FastMouse]

I guess that this is not a SRM repair. Without knowing all of the details, it is difficult to say anything definitive. Obviously, the ideal situation to to avoid creating inspectability issues, but this is not always possible.

Does anybody know if this installation is acceptable and it could be enough to include these four rivets in the ultrasounds/Eddy current inspection planned for the doubler fasteners and antenna hole?

I assume that the SDI will find damage in the 2nd layer, so that the hidden portions of the holes can be inspected through the doubler. If you think that it's acceptable, your CVE/DER/DRE thinks it's acceptable, your regulatory body thinks it's acceptable, and the client thinks it's acceptable, then yes, it's acceptable. It sounds like the way to go to me. Uncomplicated to substantiate, straight-forward to implement, routine(ish) to perform.

 

[Sparweb]

The fact that the partially covered rivets are on the installation drawing is an indication that the authorities are aware of it, and/or it was accounted for in the evaluation of the repair. They may have evaluated the effect of extending the doubler design to pick them up, and found that it wasn't worthwhile. Have you queried them about this feature of the design?

STF

 

[fjcobo]

Thank you for your answers. After check this issue with the engineering team, the solution will be to reduce dimensions of doubler so the existing rivets remain visible.
Thanks again for your help.
FJ

 

[rb1957]

i would strongly suggest not covering the 4 rivets, but project them onto your doubler.

if you want to inspect the buried rivets then you have to prove your inspection works ... a lot of work.

btw, you'll also need to inspect the fuselage under the dblr in any case ...

Quando Omni Flunkus Moritati