Document ID: chunk:federal_register_of_legislation:F2008L04604:body:0:p2
Version: federal_register_of_legislation:F2008L04604
Segment Type: other
Provision Reference: 
Character Range: 3597–6656

the effective date of this AD.

             For Requirement 2 - Before 16 December 2009.
             This Airworthiness Directive becomes effective on 15 January 2009.
Background:  This AD requires deactivation of PATS Aircraft, LLC, auxiliary fuel tanks.  This AD results from fuel system reviews conducted by the manufacturer, which identified unsafe conditions for which the manufacturer has not provided corrective actions.  The issuing of this AD is intended to prevent the potential of ignition sources inside fuel tanks, which, in combination with flammable fuel vapours, could result in fuel tank explosions and consequent loss of the aeroplane.

James Coyne
Delegate of the Civil Aviation Safety Authority

27 November 2008

AD/B737/350  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