AD/B737/331 Airworthiness Limitations and Inspections Fuel Systems (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.

Boeing 737 Series Aeroplanes

AD/B737/331 Airworthiness Limitations
and Inspections - Fuel Systems 7/2008

Applicability:	Model 737-100, -200, -200C, - 300, -400 and -500 series aeroplanes.
Requirement:	1.    Revise the approved maintenance program to incorporate the information specified the subsections below; except that the initial inspection specified in Requirement 2 must be done at the applicable compliance time specified in that Requirement.
Note 1:  The term "Revision March 2008 of Document D6-38278-CMR", as used in this Directive, means Boeing 737-100/200/200C/300/400/500 Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs), D6-38278-CMR, Revision March 2008.
a.     For Model 737-100, -200 and -200C series aeroplanes - Section C, "FUEL SYSTEMS AIRWORTHINESS LIMITATIONS," including AWLs No. 28-AWL-01 through No. 28-AWL-20 inclusive, of Revision March 2008 of Document D6-38278-CMR.  As an optional action, AWLs No. 28-AWL-21 through No. 28-AWL-23 inclusive, as identified in Section C of Revision March 2008 of Document D6-38278-CMR, also may be incorporated into the approved maintenance program.
b.    For Model 737-300, -400 and -500 series aeroplanes - Section C, "FUEL SYSTEMS AIRWORTHINESS LIMITATIONS," including AWLs No. 28-AWL-01 through No. 28-AWL-19 inclusive, Revision March 2008 of Document D6-38278-CMR.  As an optional action, AWLs No. 28-AWL-20 through No. 28-AWL-22 inclusive, as identified in Section C of Revision March 2008 of Document D6-38278-CMR, also may be incorporated into the approved maintenance program.
Accomplishing the revisions in accordance with a later revision of Document D6-38278-CMR is an acceptable method of compliance if the revision is approved by the Manager, Seattle Aircraft Certification Office (ACO) of the United States Federal Aviation Administration (FAA).

2.    For the aeroplanes identified in the "Applicability" column of AWL No.
28-AWL-03 of Section C of Revision March 2008 of Document
D6-38278-CMR - Carry out a special detailed inspection of the lightning shield to ground termination on the out-of-tank fuel quantity indication system (FQIS) wiring to verify functional integrity, in accordance with AWL No. 28-AWL-03 of Section C of Revision March 2008 of Document D6-38278-CMR.

Accomplishing the actions required by Requirement 2 in accordance with a later revision of Document D6-38278-CMR is an acceptable method of compliance if the revision is approved by the Manager, Seattle ACO.

Accomplishing AWL No. 28-AWL-03 as part of an approved maintenance program before the applicable compliance time specified for Requirement 2 constitutes compliance with that Requirement.

Note 2:  For the purposes of this Directive, a special detailed inspection is: "An intensive examination of a specific item, installation or assembly to detect damage, failure or irregularity.  The examination is likely to make extensive use of specialised inspection techniques and/or equipment.  Intricate cleaning and substantial access or disassembly procedure may be required."

3.    Repair any discrepancy found during any Requirement 2 inspection in accordance with AWL No. 28-AWL-03 of Section C of Revision March 2008 of Document D6-38278-CMR.

Accomplishing the actions required by Requirement 3 in accordance with a later revision of Document D6-38278-CMR is an acceptable method of compliance if the revision is approved by the Manager, Seattle ACO.

After accomplishing the applicable actions specified in Requirements 1 to 3 inclusive, no alternative inspections, inspection intervals or Critical Design Configuration Control Limitations (CDCCL) may be used unless the inspections, intervals or CDCCLs are part of a later revision of the Revision March 2008 of Document
D6-38278-CMR that is approved by the Manager, Seattle ACO; or unless the inspections, intervals or CDCCLs are approved as an alternate method of compliance (AMOC) to FAA AD 2008-10-09.

Actions accomplished before the effective date of this Directive in accordance with the Boeing 737-100/200/200C/300/400/500 Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs), D6-38278-CMR, Revision
May 2006, Revision September 2006 or Revision November 2007 are acceptable for compliance against the corresponding elements of Requirements 1, 2 and 3.

Note 3:  FAA AD 2008-10-09 Amdt 39-15515 refers.

Compliance:	For Requirement 1 - Before 16 December 2008.
For Requirement 2 - At the later of the following times:
a.     Within 120 months since the date of issue of the original certificate of airworthiness or the date of issue of the original export certificate of airworthiness.
b.    Within 24 months after the effective date of this Directive.
For Requirement 3 - Before further flight after the Requirement 2 inspections.
This Airworthiness Directive becomes effective on 3 July 2008.
Background:	This Directive results from a design review of the fuel tank systems.  The Directive is issued to prevent the potential for ignition sources inside fuel tanks caused by latent failures, alterations, repairs or maintenance actions, which, in combination with flammable fuel vapours, could result in a fuel tank explosion and consequent loss of the aeroplane.

James Coyne
Delegate of the Civil Aviation Safety Authority

22 May 2008