AD/B737/299 Electrical Bonding (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/B737/299 Electrical Bonding 3/2007

Applicability:	Model 737-600, -700, -700C, -800 and -900 series aeroplanes, as identified in Boeing Special Attention Service Bulletin (SB) 737-28-1225, Revision 1, dated 30 October 2006.
Requirement:	1.    Test the electrical resistance of the bond between the bulkhead fitting for the fuel feed line and the wing front spar on the left and right wings and carry out a general visual inspection of adjacent bonding jumpers to make sure they are installed correctly.  Both actions are to be accomplished in accordance with the SB 737-28-1225, Revision 1.
2.    Carry out all applicable corrective actions in accordance with SB 737-28-1225, Revision 1.
Actions accomplished before the effective date of this Directive in accordance with Boeing Special Attention Service Bulletin 737-28-1225 dated 12 January 2006, are considered acceptable for compliance with the actions required by this Directive.
Later revisions of the above SB, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2007-02-14, are considered acceptable for compliance with the equivalent Requirements of this Directive.
Note:  FAA AD 2007-02-14 refers.
Compliance:	For Requirement 1 - Within 60 months after the effective date of this Directive.
For Requirement 2 - Before further flight after the Requirement 1 electrical resistance test.
This Airworthiness Directive becomes effective on 15 March 2007.

Background: This Directive requires testing the electrical resistance of the bond between the bulkhead fitting for the fuel feed line and the front spar of the left and right wings, inspecting an adjacent bonding jumper to make sure it is installed correctly and, if necessary, performing corrective and other specified actions as applicable.  The Directive is issued to prevent arcing or sparking in the fuel tank in the event of a lightning strike, which could result in an uncontrolled fire or explosion.

James Coyne
Delegate of the Civil Aviation Safety Authority

1 February 2007