AD/CHA/27 - Exhaust Stack 'Y' Junction (Cth)

COMMONWEALTH OF AUSTRALIA (Civil Aviation Safety Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

American Champion (Aeronca, Bellanca) Series Aeroplanes

AD/CHA/27 Exhaust Stack 'Y' Junction 12/2003

Applicability: Aeronca 7AC aeroplanes with Serial Number (S/N) prior to No. 7AC-6797 and 11AC aeroplanes with S/N prior to No. 11AC-1697 fitted with mild steel exhaust stacks part numbers 7-485 and 7-486.

Requirement: Visually inspect the exhaust stacks in the vicinity of the "Y" junction for evidence of burning or flaking, tap with a hammer for evidence of soft spots, and inspect to determine whether the stack is obstructed in any way in accordance with Champion Aircraft Corporation service helps and hints #25 Revision 1.

Note: FAA AD 47-30-05 refers.

Compliance: At repetitive intervals not to exceed 50 flight hours from the effective date of this Directive.

This Airworthiness Directive becomes effective on 27 November 2003.

Background: Difficulty in the manufacture of the mild steel "Y" stacks has lead to failure of the stacks through cracking, burning, and obstruction of the "Y" stack. Failure of the stack can lead to exhaust gases entering the cabin and/or carburettor heater muffs.