AD/XL/1 Muffler Cracking (Cth)

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 39.001(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.

Liberty Aerospace XL Series Aeroplanes

AD/XL/1 Muffler Cracking 6/2009 DM

Applicability:

Liberty Aerospace Incorporated Model XL-2 aeroplanes, serial numbers 0007, 0009, and subsequent.

Requirement:

1.    Inspect the following:

a)    The exhaust muffler for cracks. There are two different exhaust systems available for the affected aeroplanes. They are:

i)     Standard exhaust system, part number (P/N) DEL200201-002 that incorporates muffler P/N DEL200201-101; and

ii)    Reduced sound exhaust system, P/N DEL200201-003 that incorporates muffler P/N 200201-104.

b)    The tail pipe and the tail pipe opening in the lower cowl for a 0.5-inch minimum clearance.

c)    Inspect the propeller for proper propeller clocking position.

2.    As a result of the inspections detailed in Requirement 1b) and 1c) of this AD:

a)    If the clearance between the tail pipe and the tail pipe opening is less than the required 0.5-inch minimum, trim the lower cowl as needed to achieve the minimum clearance.

b)    If there is a discrepancy in the propeller clocking position, remove and reinstall the propeller at the correct position.

3.    As a result of the initial inspection detailed in Requirement 1a) of this AD or any repetitive inspection as detailed in Requirement 5 of this AD, if a crack is found, replace the exhaust muffler.

a)    The manufacturer will provide the replacement exhaust system.

b)    A reduced sound exhaust system may be replaced with a standard exhaust system.

c)    Installing a reduced sound exhaust system as a replacement part also requires installing a bypass SCAT tube and a "Do Not Use" placard on or near the heater knob.

4.    If the aeroplane is equipped with a reduced sound exhaust system and no cracks are found during the initial inspection detailed in Requirement 1 of this AD, install a bypass SCAT tube and a "Do Not Use" placard on or near the heater knob.

5.    Carry out repetitive inspections if no cracks are found in the exhaust muffler during the initial inspection detailed in Requirement 1 of this AD or if the exhaust muffler was replaced as detailed in Requirement 3 of this AD.

6.    Report the results of the following inspections required in this AD to CASA via the service difficulty reporting system.  A reporting form is included in Appendix 1 for your convenience.

a)    Initial inspection as detailed in Requirement 1 of this AD.

b)    Repetitive inspections as detailed in Requirement 5 of this AD only if cracks are found.

Note:  FAA AD 2009-08-05 Amdt 39-15878 dated 3 April 2009 refers.

Compliance:

For Requirement 1 - Initially inspect within the next 10 hours time-in-service (TIS) after the effective date of this AD or at the next annual inspection, whichever occurs first. Repetitively inspect the exhaust muffler thereafter as specified Requirement 5 of this AD.

For Requirement 2 - Before further flight.

For Requirement 3 - Before further flight after the initial inspection detailed in Requirement 1a) of this AD and before further flight after any repetitive inspection as specified Requirement 5 of this AD.

For Requirement 4 - Within the next 10 hours TIS after the effective date of this AD.

For Requirement 5 - For aeroplanes equipped with a standard exhaust system and the optional bypass SCAT tube has not been installed, repetitively inspect thereafter every 25 hours TIS or every 12 months, whichever occurs first; and

For aeroplanes equipped with a standard exhaust system and the optional bypass SCAT tube has been installed, repetitively inspect thereafter every 50 hours TIS or every 12 months, whichever occurs first; and

For aeroplanes equipped with a reduced sound exhaust system and the required bypass SCAT tube has been installed, repetitively inspect thereafter every 50 hours TIS or every 12 months, whichever occurs first.

For Requirement 6 - Within 7 days after completion of the relevant inspection.

This Airworthiness Directive becomes effective on 21 April 2009.

Background:

This AD is the result of reports that eight cracks have been found in the exhaust muffler during maintenance and service inspections.  The issuing of this AD is intended to detect and correct cracks in the exhaust muffler, which could result in carbon monoxide entering the cabin heating system.  This condition could lead to incapacitation of the pilot.

James Coyne
Delegate of the Civil Aviation Safety Authority

17 April 2009

AD/XL/1
Appendix 1 Muffler Cracking 6/2009 DM

Inspection Report
Aeroplane Serial Number
Aeroplane Tach Hours at time of inspection
Propeller type (circle one)	MT	Sensenich
Propeller Tach Hours at time of inspection
Exhaust Type (circle one)	Standard	Reduced Sound
Is exhaust cracked?	Yes	No
Did lower cowl require trimming at the tail pipe opening ?(circle one) Not applicable after the initial inspection	Yes	No
Did the propeller clocking position need to be corrected? (circle one) Not applicable after the initial inspection	Yes	No
Were any other discrepancies noticed during the inspection