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AD/B737/291 - Auxiliary Fuel Tank Float Switch
Boeing 737 Series AeroplanesBoeing 737 Series Aeroplanes
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Boeing 737 Series Aeroplanes
| AD/B737/291 | Auxiliary Fuel Tank Float Switch | 9/2006 |
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| Applicability: | Model 737-200, -300, and -400 series aeroplanes, equipped with auxiliary fuel tanks. |
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| Requirement: | 1. Replace the existing fuelling float switch in the auxiliary fuel tank with a new, improved fuelling float switch, install a new liner system inside the float switch conduit in accordance with Part A of the Accomplishment Instructions of Boeing Service Bulletin (SB) 737-28A1192, Revision 2, dated 27 April 2006. |
| Note 1: This Directive does not require doing the actions in Part B of the Accomplishment Instructions of Boeing Service Bulletin 737- 28A1192, Revision 2. | |
| Replacements and conduit liner system installations accomplished before the effective date of this Directive in accordance with Boeing Alert Service Bulletin 737-28A1192, dated 27 March 2003; or Boeing SB 737-28A1192, Revision 1, dated 21 August 2003; are acceptable for compliance with the requirements of this Directive. | |
| 2. Fuelling float switch part number (P/N) F8300-146 may not be installed on the auxiliary fuel tank of any aeroplane as a replacement spare. | |
| Note 2: FAA AD 2006-15-05 Amdt 39-14685 refers. | |
| Compliance: | For Requirement 1 - Within 24 months after the effective date of this Directive. |
| For Requirement 2 - As of the effective date of this Directive. | |
| This Airworthiness Directive becomes effective on 31 August 2006. |
| Background: | The United States Federal Aviation Administration (FAA) has received reports of chafing of the direct-current-powered float switch wiring insulation in the centre fuel tank. This Directive requires actions designed to prevent contamination of the fuelling float switch of the auxiliary fuel tank by moisture or fuel, together with chafing of the float switch wiring against the float switch conduit in the fuel tank, which could present an ignition source inside the fuel tank that could cause a fire or explosion. |
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Image unavailable in extracted text James Coyne Delegate of the Civil Aviation Safety Authority