Document ID: chunk:federal_register_of_legislation:F2008L04605:body:0:p2
Version: federal_register_of_legislation:F2008L04605
Segment Type: other
Provision Reference: 
Character Range: 2898–5687

27 November 2008

AD/B767/249  Auxiliary Fuel Tanks  1/2009
Appendix A

Deactivation Criteria

The auxiliary fuel tank deactivation procedure as detailed in Requirement 2 of this AD should address the following actions.

   1. Permanently drain auxiliary fuel tanks, and clear them of fuel vapours to eliminate the possibility of out-gassing of fuel vapours from the emptied auxiliary tank.

   2. Disconnect all electrical connections from the fuel quantity indication system (FQIS), fuel pumps if applicable, float switches, and all other electrical connections required for auxiliary tank operation, and stow them at the auxiliary tank interface.

   3. Disconnect all pneumatic connections if applicable, cap them at the pneumatic source, and secure them.

   4. Disconnect all fuel feed and fuel vent plumbing interfaces with aeroplane original equipment manufacturer (OEM) tanks, cap them at the aeroplane tank side, and secure them in accordance with a method approved by CASA; one approved method is specified in AC 25-8 Auxiliary Fuel System Installations.  In order to eliminate the possibility of structural deformation during cabin decompression, leave open and secure the disconnected auxiliary fuel tank vent lines.

   5. Pull and collar all circuit breakers used to operate the auxiliary tank.

   6. Revise the weight and balance document, if required, and obtain CASA approval.

   7. Amend the applicable sections of the applicable aeroplane flight manual (AFM) to indicate that the auxiliary fuel tank is deactivated.  Remove auxiliary fuel tank operating procedures to ensure that only the OEM fuel system operational procedures are contained in the AFM.  Amend the Limitations Section of the AFM to indicate that the AFM Supplement for the STC is not in effect.  Place a placard in the flight deck indicating that the auxiliary tank is deactivated.  The AFM revisions specified in this paragraph may be accomplished by inserting a copy of this AD into the AFM.

   8. Amend the applicable sections of the applicable aeroplane maintenance manual to remove auxiliary tank maintenance procedures.

   9. After the auxiliary fuel tank is deactivated, accomplish procedures such as leak checks and pressure checks deemed necessary before returning the aeroplane to service.  These procedures must include verification that the aeroplane FQIS and fuel distribution systems have not been adversely affected.

   10. Revise the instructions for continued airworthiness, as required, after deactivation.

   11. Include with the operator's proposed procedures any relevant information or additional steps that are deemed necessary by the operator to comply with the deactivation and return the aeroplane to service.