AD/J4100/24 Fuel Boost Pump and Fuel Tank High Level Sensor Wiring (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.

BAe Systems (Operations) Jetstream 4100 Series Aeroplanes

AD/J4100/24 Fuel Boost Pump and Fuel Tank
High Level Sensor Wiring 5/2008 DM

Applicability:

Jetstream 4100 series aeroplanes, all models, all serial numbers.

Requirement:

1.    Modify the left (LH) and right (RH) wing fuel boost pump wiring in accordance with paragraphs 2B and 2C of BAE Systems (Operations) Ltd Service Bulletin (SB) J41-28-014 Revision 1 dated 21 December 2007.

2.    Inspect the LH and RH wing fuel high level sensor wiring in accordance with paragraph 2D of SB J41-28-014 Revision 1.

3.    If excess wiring and/or damaged wiring is found during the Requirement 2 inspection, accomplish the corrective actions as specified in paragraph 2D
SB J41-28-014 Revision 1.

Later revisions of SB J41-28-014, approved by the European Aviation Safety Agency (EASA), are acceptable for compliance with the requirements of this Directive.

Note:  EASA AD 2008-0041 refers.

Compliance:

For Requirement 1 and 2 - At the next major inspection or wing tank access, or within 24 months after the effective date of this Directive, whichever occurs first.

For Requirement 3 - Before the next flight after the Requirement 2 inspection.

This Airworthiness Directive becomes effective on 14 March 2008.

Background:

Following the assessment of fuel tank wiring installations required by SFAR 88 and equivalent JAA/EASA policy, BAE Systems identified two features in the Jetstream 4100 where the need for design changes was apparent.  One of these is addressed by SB J41-28-014 which introduces changes to the wiring harness installations to the LH and RH fuel boost pumps, identified by modification number JM41672.  In addition, to detect excessive cable lengths and evidence of chafing damage, SB J41-28-014 provides instructions to inspect and correct, as necessary, the internal fuel tank wiring routed to the LH and RH high level sensors.

Internal fuel tank wiring chafing damage, if not corrected, could lead to ignition of fuel vapours and subsequent fuel tank explosion.

For the reason stated above, this Directive requires the replacement of the (LH and RH) fuel boost pump metallic conduit assemblies with loom assemblies and the inspection of internal fuel tank high level sensor wiring, together with corrective actions, as necessary.

David Punshon
Delegate of the Civil Aviation Safety Authority

5 March 2008