Document ID: chunk:federal_register_of_legislation:F2009L02244:body:0:p2
Version: federal_register_of_legislation:F2009L02244
Segment Type: other
Provision Reference: 
Character Range: 3284–6633

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              On aircraft where the following STCs are installed, the actions detailed in this AD are no longer applicable and the Zonal Drying System accordingly modified can be re-activated.

              Table 2.
              STC Number                 Issued by  Holder                Applicable to
              EASA.A.S.03502 Revision 1  EASA       Lufthansa Technik AG  Bombardier
                                                                          CL-600-2B19
              EASA.A.S.03504 Revision 1  EASA       Lufthansa Technik AG  Boeing 737-700
              EASA.A.S.03505 Revision 1  EASA       Lufthansa Technik AG  Boeing 737-800

             EASA.A.S.03506 Revision 1  EASA  Lufthansa Technik AG  Boeing 747-400
             EASA.A.S.03507 Revision 1  EASA  Lufthansa Technik AG  Airbus A330-200
             EASA.A.S.02547 Revision 2  EASA  CTT Systems AB        Boeing 767-300
             EASA.A.S03738              EASA  CTT Systems AB        Boeing MD 11
             EASA.A.S.03844 Revision 1  EASA  Jet Aviation          Boeing 737-100 IGW (S/N 32627)

             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 2006-0140R4 dated 17April 2009 refers.
Compliance:  Before further flight after the effective date of this AD, unless previously accomplished.
             This Amendment becomes effective on 2 July 2009.
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 4 includes additional STCs that are approved as terminating action to this AD and updates the revision status of STC EASA.A.A.02547 in Table 2 of this AD.

   Amendment 3 included additional STCs that are approved as terminating action to this AD.

   Amendment 2 became effective on 20 November 2008.

   Amendment 1 of this AD became effective on 26 May 2006.

   The original issue of this AD became effective on 19 May 2006.

James