AD/B737/121 Amdt 2 Fuel Boost Pump Wiring (Cth)

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B737/121 Amdt 1 and issues the following 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/B737/121 Amdt 2 Fuel Boost Pump Wiring 13/2006

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.
a.    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:

a.    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:

a.    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:

a.    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.
Later revisions of the above SBs, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 99-21-15, are considered acceptable for compliance with the equivalent Requirements of this Directive.
Note:  FAA AD 99-21-15 Amdt 39-11360 refers.
Compliance:	For Requirement 1 - Remains unchanged as ‘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 21 December 2006.
Background	This amendment allows compliance in accordance with later revisions of certain service bulletins.
Amendment 1 introduced minor formatting changes, maked the Requirement 1 inspection repetitive, which removed the optional Teflon sleeving terminating action, deleted Requirement 12 and added 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 30,000 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 30,000 hours total time in service.
The original issue of this Directive became effective on 14 October 1998.
Amendment 1 became effective on 23 March 2000.

James Coyne
Delegate of the Civil Aviation Safety Authority

9 November 2006