AD/B747/312 - Fire Extinguisher System Tube (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 39.1 (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 747 Series Aeroplanes

AD/B747/312 Fire Extinguisher System Tube 10/2004

Applicability: Model 747-400 and 747-400D series aeroplanes, as listed in Boeing Service Bulletin (SB) 747-26A2270, Revision 2 dated 26 June 2003.

Requirement: Either inspect or pressure test the fire extinguishing system tube as detailed in Requirement 1 or 3 of this Directive.

1. Perform a detailed inspection of the fire extinguishing system tube and clamps for correct installation, either using an inspection hole and boroscope or with the floor panel removed, per Boeing SB 747-26A2270 Revision 2. If the fire extinguishing system tube is installed correctly no further action is required by this Directive.

2. If the fire extinguishing system tube is installed incorrectly, remove the fire extinguishing system tube and perform a detailed inspection of the fire extinguishing system tube for chafing/damage per Boeing SB 747-26A2270 Revision 2.

1. If no chafing/damage is found, install the existing fire extinguishing system tube per Figure 3 of Boeing SB 747-26A2270 Revision 2.