SPA sent out a mandatory Service Bulletin calling for installation of a brace to support the flap detent mounting point, to prevent potential breakage at the weld on early frame weldments.
To satisfy this bulletin, I fabricated an aluminum support bracket from aluminum angle that attaches to the upper flap detent plate mounting bolt, and extends back to, and is riveted to the fuselage floor tube behind the flap system.
Flap Detent Plate Brace
Brace Riveted to Fuselage Tube Behind the Flap Detent Plate