80-21-06: Muffler Core and Body Assembly

80-21-06 BELLANCA (CHAMPION): Amendment 39-3939. Applies to Bellanca (Champion) Models 7GC, 7GCB, 7HC, 7KC, 7GCA, 7GCBA, 7ECA (Serial Numbers prior to 985-74), 7GCAA (Serial Numbers prior to 280-74), 7GCBC (Serial Numbers prior to 604-74), 7KCAB (Serial Numbers prior to 405-74), and 8KCAB (Serial Numbers prior to 120-74). Compliance is required within the next 25 hours time in service, or 60 days after the effective date of this AD, whichever occurs first, and thereafter at intervals not to exceed 100 hours time in service, or 12 months from the last inspection, whichever occurs first. To prevent a degradation of the induction system icing protection or partial engine power loss, accomplish the following: (1) Visually inspect the baffle installation within the muffler core and body assemblies, Bellanca (Champion) P/Ns 3-1079 or 3-1493, for cracking or deterioration, with the mufflers removed from the aircraft. Replace any muffler where baffle cracking or deteriorationis evident, with an airworthy muffler core and body assembly of the same or other FAA approved part number. (2) If an airplane is at an unsuitable base when compliance with this AD is required, the airplane may be issued a special flight permit in accordance with FAR 21.197 and 21.199 for the purpose of flying to a base where the required inspection may be performed. (3) Equivalent methods of complying with this AD, including the installation of different exhaust systems, must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Great Lakes Region. This amendment becomes effective October 16, 1980.