AD/Aircon/14 Amdt 2 Zonal Drying System Regeneration Air Duct Overheat (Cth)
AIRWORTHINESS DIRECTIVE
On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/AIRCON/14 Amdt 1 and issues the following 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.
Airconditioning Equipment
| AD/AIRCON/14 Amdt 2 | Zonal Drying System Regeneration Air Duct Overheat | 12/2008 |
Applicability: | CTT Systems AB Zonal Drying System P/N 1000-001, 2000-000, 2000-005, Note 1: These are known to be installed in, but not limited to, Airbus A330-243 and A330-322; Boeing 737-700, 737-800, 747-400, and 767-300 series; Bombardier The following STCs have been identified to be affected by the requirements of this AD. The approval list for the installation of the affected Zonal Drying System in Table 1 may be not exhaustive. In case the relevant aircraft are not listed therein, this does not exempt any aircraft having an affected Zonal Drying System P/N installed from compliance with this directive. Table 1.
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Note 2: LBA.21E2.TA0636 was approved by EASA under Approval Number Note 3: RLD STC SA 0009 NL has been superseded by EASA.A.S.02547 on | |||||||||||||||||||||||||
Requirement: | Switch off the Zonal Drying System installed in accordance with one of the STCs listed in Table 1 of the Applicability section of this AD and set system inoperative by pulling and securing the affected circuit breaker in accordance with relevant maintenance instructions. Terminating Action. On aircraft where the following STCs are installed, the actions detailed in this AD are no longer applicable and the Zonal Drying System accordingly modified can be re-activated.
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| CTT Systems AB Information Letters IL06-01 dated 5 May 2006, IL06-02 issue 2 dated 8 May 2006 and IL06-03 dated 10 May 2006; and (for Lufthansa Technik STCs only) Lufthansa Technik AG Service Information Letter LHT 06-001, Revision IR dated 12 May 2006 pertains to this AD. The use of later approved revisions of these documents is acceptable for compliance with the requirements of this AD. Note 4: EASA AD 2006-0140R2 dated 2 October 2008 refers. | |
Compliance: | Remains unchanged as detailed in amendment 1 of this AD as: Before further flight after 19 May 2006, unless previously accomplished. |
| This Amendment becomes effective on 20 November 2008. | |
Background: | One incident had been reported where the regeneration air ducting downstream of a Zonal Drying System P/N 3000-002, installed in a Boeing 747-400 aircraft, showed signs of premature material failure. As the root cause for the failure was initially not known, all other Zonal Drying Systems of similar design could have been affected by the same unsafe condition, the original issue of this AD mandated their de-activation. Investigation showed that such failure was caused by combustion of contaminants in the dryer unit. This amendment is issued following the development of a new dryer unit which removes this combustion risk. The installation of the new dryer unit is now approved through the EASA STCs listed in Table 2 of the Required action and Compliance Time section of this AD and once installed in a subject aircraft corrects the unsafe condition and terminates the requirements of this AD. Consequently, the Zonal Drying System can be re-activated. Amendment 1 of this AD became effective on 26 May 2006. The original issue of this AD became effective on 19 May 2006. |
Charles Lenarcic
Delegate of the Civil Aviation Safety Authority
3 October 2008
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