Originally Posted by
SLFstu
Clean Break?
Intruder asked "How do you get such a clean break all the way around that tail cone? Is that seam an engineered weak point?" (#594).
...to which oleostrut (#595) postulated that the original strength is largely in the skin, supported by ribs, frames, etc.
Actually, according to Airbus confidential drawings (thank you Mr google) the whole tailcone subassembly is bolted to the rest of the empennage via attachment lugs at 4 points. None of those large lugs is visible in the crash photos. In TylerMonkey's photo (#581) showing "better detail" of the tailcone front firewall, the location of 1 of the missing lugs would be expected in the top left of the photo - in the position of the triangular hole in the outermost frame.
Not sure if my original post is still in moderation or got binned. However, considering the above and subsequent drawings I'll repost.
2014-0177 : Fuselage – Rear Fuselage Clips, Shear Webs and Angles – Replacement
EASA Airworthiness Directives Publishing Tool
During the A320 fatigue test campaign for Extended Service Goal (ESG), it was determined that fatigue damage could appear on the clips, shear webs and angles at rear fuselage section 19, on Frame (FR) 72 and FR74.
This condition, if not detected and corrected, could affect the structural integrity of the aeroplane.
To address this potential unsafe condition, Airbus developed a modification,
which has been published through Airbus Service Bulletin (SB) A320-53-1266 for in-service application to allow aeroplanes to operate up to the new ESG limit.
For the reasons described above, this AD requires replacement of the affected clips, shear webs and angles at rear fuselage section 19, FR72 and FR74.
Not sure which specific area frames 72 and 74 are in. Is this the same thing you are talking about?