Commonwealth legislation

AD/CESSNA 120/12 - Carburettor and Cabin air heater muffs

In ForceCTH

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

3/10 complexity

This Airworthiness Directive requires owners/operators of Cessna 120 and 140 aeroplanes fitted with welded exhaust muffler assemblies to remove and inspect the carburettor and cabin heater muffs for cracks and to change any placard inspection interval from 100 to 25 flight hours (Applicability; Requirement; Compliance). Inspections must begin within 25 flight hours and repeat every 25 hours to address the risk of hazardous gases entering the cockpit if muffs crack (Background). Owners/operators bear inspection and repair costs; CASA issued the directive (Requirement; Compliance).

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AIRWORTHINESS DIRECTIVE

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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.

View image in the official source

Cessna 120 and 140 Series Aeroplanes

AD/CESSNA 120/12 Carburettor and Cabin A

AD/CESSNA 120/12 Carburettor and Cabin Air Heater Muffs 12/2003

Applicability: All Cessna 120 and 140 aeroplanes equipped with Cessna welded exhaust muffler assemblies where the exhaust muffler assemblies are fabricated by welding the exhaust stacks to the muffler.

Requirement: 1. Remove the carburettor air heater muff and cabin heater muff and inspect the muffler assemblies for evidence of cracks paying particular attention to the areas of the mufflers and stacks adjacent to where the exhaust stacks and tailpipe are welded to the muffler assembly.

Any placard calling for an inspection of the mufflers every 100 flight hours should be revised to call for the inspection every 25 flight hours.

Note: FAA AD 48-25-02 refers.

Compliance: 1. Initial inspection within 25 flight hours from effective date of this Directive, or 25 flight hours from the last inspection, thereafter at intervals of 25 hours.

At the first inspection of the muffler assemblies detailed in this Directive. This Airworthiness Directive becomes effective on 27 November 2003.

Background: Cracking of the heater muff could lead to hazardous gases entering the cockpit.

View image in the official source

Jim Coyne

Delegate of the Civil Aviation Safety Authority 14 October 2003

View image in the official source

The above AD is notified in the Commonwealth of Australia Gazette on 5 November 2003.

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

AIRWORTHINESS DIRECTIVE AIRWORTHINESS DIRECTIVE

AIRWORTHINESS DIRECTIVE

Cessna 120 and 140 Series Aeroplanes

AD/CESSNA 120/12 Carburettor and Cabin A AD/CESSNA 120/12 Carburettor and Cabin Air Heater Muffs 12/2003

AD/CESSNA 120/12 Carburettor and Cabin Air Heater Muffs 12/2003

Any placard calling for an inspection of the mufflers every 100 flight hours should be revised to call for the inspection every 25 flight hours.

Note: FAA AD 48-25-02 refers.

Compliance: 1. Initial inspection within 25 flight hours from effective date of this Directive, or 25 flight hours from the last inspection, thereafter at intervals of 25 hours.

At the first inspection of the muffler assemblies detailed in this Directive. This Airworthiness Directive becomes effective on 27 November 2003.

Background: Cracking of the heater muff could lead to hazardous gases entering the cockpit.

Jim Coyne

Delegate of the Civil Aviation Safety Authority 14 October 2003

The above AD is notified in the Commonwealth of Australia Gazette on 5 November 2003.