61-20-02: Exhaust Stack Reinforcement

61-20-02 PIPER: Amdt. 336 Part 507 Federal Register September 20, 1961. Applies to Model PA-24 "250" Aircraft Serial Numbers 24-103 to 24-1629 Inclusive, Which Do Not Have a Reinforcing Plate Welded to the Stack in the Area Where the Rear Engine Cylinder Stack is Welded to the Exhaust Stack Assembly. Compliance required as indicated. Due to incidents of cracks occurring in the exhaust stack assembly, right side, P/N 21664-03, the following inspections and reinforcement must be accomplished: (a) Within 25 hours' time in service after effective date of this AD, remove the carburetor heat shroud assembly, P/N 21664-03, for any indication of cracks or deterioration particularly in the area where the rear engine cylinder exhaust stack is welded to the exhaust stack assembly. If evidence of cracks or deterioration is noted, the assembly must be replaced with a new assembly prior to further flight. The provisions of this paragraph shall be reaccomplished at intervals of50 hours' time in service until such time as the installation in paragraph (b) is accomplished. (b) Within 100 hours' time in service after initial compliance with paragraph (a), a clamp-on reinforcement Piper Kit No. 754396 or equivalent, shall be installed on the exhaust stack assembly, P/N 21664-03. After installation of the clamp-on reinforcement, the provisions of paragraph (a) are no longer applicable. (Piper Service Bulletin 202 dated May 22, 1961, applies to this subject.) This directive effective October 20, 1961.