AD/B737/121 Amdt 1 - Fuel Boost Pump Wiring

Administered by Department of Infrastructure, Transport, Regional Development, Communications, Sport and the Arts

Legislation au F2006B02823 Not in force Legislative Instrument

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Boeing 737 Series Aeroplanes

 

AIRWORTHINESS DIRECTIVE


For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B737/121 and issues the following AD under subregulation 39.1 (1) of CAR 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 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.

 

AD/B737/121

Amdt 1


Fuel Boost Pump Wiring 3/2000

 

Applicability: All model 737-100 -200, -300, -400 and -500 series aeroplanes.

 

Requirement: 1. For all aeroplanes that have accumulated 20,000 or more hours total time in service and less than 30,000 hours total time in service, as of the effective date of this Directive - Unless previously accomplished in accordance with AD/B737/119, Amdt 1 or Amdt 2 remove the fuel boost pump wiring from the

in-tank conduit for the aft boost pumps in main tanks numbers 1 and 2 and centre tanks left and right boost pumps; then perform a detailed visual inspection to detect damage of the wiring, in accordance with the procedures specified in Boeing Alert Service Bulletin (ASB) 737-28A1120 dated 24 April 1998, as revised by Notice of Status Change (NSC) 01 dated 7 May 1998, NSC 02 dated 8

May 1998 and NSC 03 dated 9 May 1998; ASB 737-28A1120 Revision 1 dated

28 May 1998 or Revision 2 dated 26 November 1998.

 

2.          If red, yellow, blue or green wire insulation cannot be seen through the outer jacket of the electrical cable during the Requirement 1 inspection, accomplish the following actions in accordance with the procedures specified in Boeing ASB 737-28A1120 dated 24 April 1998, as revised by NSC 01 dated 7 May 1998, NSC 02 dated 8 May 1998 and NSC 03 dated 9 May 1998; ASB 737-28A1120 Revision 1 dated 28 May 1998 or Revision 2 dated 26 November 1998.

 

  1. Install Teflon sleeving over the electrical cable and reinstall the cable, or

 

b.    Reinstall the electrical cable without Teflon sleeving over the cable, or

 

c.    Replace the electrical cable with new cable without Teflon sleeving.

 

3.          If Requirement 2.b is applied, repeat the Requirement 1 inspection and then install Teflon sleeving over the cable.

 

4.          If Requirement 2.c is applied, repeat the Requirement 1 inspection and then install Teflon sleeving over the cable.

 

 

5.          If red, yellow, blue or green wire insulation can be seen through the outer jacket of the electrical cable during the Requirement 1, 2, 3 or 4 inspections, but no evidence of electrical arcing is found, accomplish the following actions in accordance with the procedures specified in Boeing ASB 737-28A1120 dated 24 April 1998, as revised by NSC 01 dated 7 May 1998, NSC 02 dated 8 May 1998 and NSC 03 dated 9 May 1998; ASB 737-28A1120 Revision 1 dated 28 May 1998 or Revision 2 dated 26 November 1998:

 

  1. Replace the electrical cable with a new cable, install Teflon sleeving over the cable and reinstall the cable, or

 

b.    Replace the electrical cable with a new cable without Teflon sleeving.

 

6.          If Requirement 5.b is applied, repeat the Requirement 1 inspection and then install Teflon sleeving over the cable.

 

7.          If any evidence of electrical arcing, but no evidence of fuel leakage is found on the removed cable during the Requirement 1 inspection, accomplish the following actions in accordance with the procedures specified in Boeing ASB 737-28A1120 dated 24 April 1998, as revised by NSC 01 dated 7 May 1998, NSC 02 dated 8 May 1998 and NSC 03 dated 9 May 1998; ASB 737-28A1120 Revision 1 dated 28 May 1998 or Revision 2 dated 26 November 1998:

 

  1. Verify the integrity of the conduit in accordance with the instructions contained in either NSC 03, ASB 737-28A1120 Revision 1 or Revision 2 of the ASB, and

 

b.    Accomplish either of the following actions:

 

(i)       Replace the damaged electrical cable with a new cable, install Teflon sleeving over the cable and reinstall the cable, or

 

(ii)    Replace the electrical cable with a new cable without Teflon sleeving.

 

8.          If Requirement 7.b.(ii) is applied, repeat the Requirement 1 inspection and then install Teflon sleeving over the cable.

 

9.          If any evidence of fuel is found on the removed cable during the Requirement 1 inspection, accomplish the following actions in accordance with the procedures specified in Boeing ASB 737-28A1120 dated 24 April 1998, as revised by NSC 01 dated 7 May 1998, NSC 02 dated 8 May 1998 and NSC 03 dated 9 May 1998; ASB 737-28A1120 Revision 1 dated 28 May 1998 or Revision 2 dated 26 November 1998:

 

  1. Replace the conduit section where the arcing was found, and

 

 

b.    Accomplish either of the following actions:

 

(i)       Replace the damaged electrical cable with a new cable, install Teflon sleeving over the cable and reinstall the cable, or

 

(ii)     Replace the electrical cable with a new cable without Teflon sleeving.

 

10.     If Requirement 9.b.(ii) is applied, repeat the Requirement 1 inspection and then install Teflon sleeving over the cable.

 

11.     For Groups 1 and 2 aeroplanes, as identified in Boeing ASB 737-28A1120 dated 24 April 1998, replace the case ground wire with a new wire in accordance with Boeing ASB 737-28A1120 dated 24 April 1998, as revised by NSC 01 dated 7 May 1998, NSC 02 dated 8 May 1998 and NSC 03 dated 9 May 1998; ASB 737- 28A1120 Revision 1 dated 28 May 1998 or Revision 2 dated 26 November 1998.

 

12.      Deleted.

 

Note: FAA AD 99-21-15 Amdt 39-111360 refers.

 

Compliance: For Requirement 1 - Prior to 14 December 1998 (the date required by the original issue of this Directive) and thereafter at intervals not to exceed 30,000 hours time in service.

 

For Requirement 2 - Prior to further flight, immediately following the Requirement 1 inspection.

 

For Requirement 3 - Within 500 hours time in service after the cable reinstallation.

 

For Requirement 4 - Within 18 months or 6,000 hours time in service, which ever occurs first, after the cable replacement.

 

For Requirement 5 - Prior to further flight, immediately following the Requirement 1 inspection.

 

For Requirement 6 - Within 18 months or 6,000 hours time in service, which ever occurs first, after the cable replacement.

 

For Requirement 7 - Prior to further flight, immediately following the Requirement 1 inspection.

 

For Requirement 8 - Within 18 months or 6,000 hours time in service, which ever occurs first, after the cable replacement.

 

For Requirement 9 - Prior to further flight, immediately following the Requirement 1 inspection.

 

 

For Requirement 10 - Within 18 months or 6,000 hours time in service, which ever occurs first, after the cable replacement.

 

For Requirement 11 - Prior to further flight, immediately following the Requirement 1 inspection.

 

This Amendment becomes effective on 23 March 2000.

 

Background This amendment introduces minor formatting changes, makes the Requirement 1 inspection repetitive, which removes the optional Teflon sleeving terminating action, deletes Requirement 12 and adds ASB Revision 2 to the requirement statements.

 

Since the issuing of FAA AD T98-11-52, the FAA has received additional reports of severe wear of fuel boost pump wiring on model 737 series aeroplanes that had accumulated 29,000 and 35,000 hours total time in service. Some of the aeroplanes had accumulated fewer hours total time in service than the number of hours specified as the inspection threshold in AD T98-11-52, as a result, the FAA has expanded the inspection requirements to include aircraft that have accumulated between 20,000 and 30,00 hours total time in service.

 

This original issue of this Directive did not supersede AD/B737/119 Amdt 1, but introduced inspections for aircraft that had accumulated between 20,000 and 30,00 hours total time in service.

 

The original issue of this directive became effective on 14 October 1998.


 

Eugene Paul Holzapfel

Delegate of the Civil Aviation Safety Authority 15 February 2000

 

 

 

 

 

 

 

 

 

 

 

 


The above AD is notified in the Commonwealth of Australia Gazette on 23 February 2000.

Overview

The Civil Aviation Safety Authority Act 1997 was enacted to provide for the safety of civil aviation within Australia. This Act established the Civil Aviation Safety Authority (CASA) to regulate the safety aspects of civil aviation, including the issuance of airworthiness directives to address identified safety issues. The Boeing 737 Series Aeroplanes Airworthiness Directive (AD/B737/121) issued by CASA in 2000 is an example of such measures aimed at mitigating safety risks associated with specific aircraft models. This particular directive was introduced to address the issue of severe wear of fuel boost pump wiring on Boeing 737 series aeroplanes, which had accumulated between 20,000 and 30,000 hours of total time in service. The policy objective of this directive is to ensure the continued airworthiness and safety of the affected aircraft by mandating specific inspections and corrective actions as outlined in the directive.

Scope and Application

This Airworthiness Directive (AD) issued by the Civil Aviation Safety Authority (CASA) applies specifically to Boeing 737 Series aeroplanes, including models 737-100, -200, -300, -400, and -500. The directive mandates certain actions to correct an unsafe condition identified in the wiring of the fuel boost pump in these aeroplanes. The AD applies to all such aeroplanes that have accumulated between 20,000 and 30,000 hours of total time in service. The specified actions include the removal of the fuel boost pump wiring from designated conduits, conducting a detailed visual inspection of the wiring for damage, and performing subsequent corrective actions based on the findings of the inspection. The directive outlines precise procedures to be followed, referencing specific Boeing Alert Service Bulletins and their revisions, and mandates specific timelines for compliance with the AD's requirements. The AD does not supersede existing directives but introduces additional inspection requirements for the specified aeroplanes within the defined time in service range.

Key Provisions

The main operative sections of this Airworthiness Directive (AD) mandate specific actions to ensure the safety of Boeing 737 series aeroplanes. Section (a) of the applicability section identifies the aircraft subject to the AD, specifically all model 737-100, -200, -300, -400, and -500 series aeroplanes. The requirement section outlines detailed actions to be taken under specific circumstances, such as the removal of fuel boost pump wiring, inspections for damage or electrical arcing, and replacement of affected components. Compliance with these requirements is essential to maintain the airworthiness of the specified aircraft. The AD imposes several obligations on the parties it governs. Operators and owners of the specified Boeing 737 series aeroplanes must ensure that the actions outlined in the requirement section are carried out. This includes conducting detailed visual inspections of the fuel boost pump wiring, as per the procedures specified in the Boeing Alert Service Bulletin (ASB) 737-28A1120 and its revisions. Furthermore, the AD mandates that any identified issues, such as damaged wiring or electrical arcing, must be addressed immediately or within specified time frames to maintain compliance. Operators must also adhere to the compliance timelines provided, ensuring that inspections and corrective actions are completed within the prescribed intervals or flight hours. Failure to comply with the requirements of this AD can result in significant consequences. The AD does not explicitly state penalties but implies that non-compliance could lead to the grounding of the aircraft until the necessary actions are taken, which could result in operational disruptions and financial losses. Additionally, continued operation of an aircraft that does not meet the airworthiness standards set by this AD could result in severe safety risks, potentially leading to accidents or incidents that could endanger lives and property. Therefore, adherence to this AD is critical to ensure the safe operation of the affected Boeing 737 series aeroplanes.

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