AIRWORTHINESS DIRECTIVE
For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B747/251 and issues the following 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/B747/251
Amdt 1
Fuel Quantity Indicating System Wiring 4/2004
Applicability: All Model 747-100, -200, -300, -SP and -SR series aeroplanes.
Requirement: Replace all the fuel quantity indication system (FQIS) wiring outside of the fuel tanks and surge tank with shielded wiring and install the new wiring so as to provide separation of that wiring from other aeroplane systems wiring in accordance with a method approved by Manager, Seattle Aircraft Certification Office, Federal Aviation Administration (FAA), Transport Airplane Directorate.
Installations of Smiths Industries Transient Suppression Units in accordance with Boeing SB 747-28-2233 dated 22 February 2001 (FAA STC ST00181SE refers), or in accordance with methods approved in FAA Letters 130S-00-0391 or 130S-03-375 are considered acceptable means of compliance with this Directive.
Note: FAA AD 98-20-40 Amdt 39-10808 refers.
Compliance: Remains unchanged as ‘Before 31 December 2001’.
This Amendment becomes effective on 15 April 2004.
Background: The FAA issued AD 98-20-40 following a failure analysis of the FQIS system and testing, which revealed that excessive energy levels in the electrical wiring and probes of the fuel system could be induced by electrical transients. The original Directive required actions intended to prevent electrical transients, introduced by electromagnetic interference or electrical short circuits from causing arcing of the FQIS electrical wiring or probes in the fuel tank(s). Such arcing could result in ignition of the fuel tank(s). The Directive also included FAA STC ST00181SE as an alternate method of compliance.
This amendment introduces an additional alternate method of compliance to allow the use of alternate indicators in previously modified aeroplanes.
Boeing 747 Series Aeroplanes
AD/B747/251 Amdt 1 (continued)
The original issue of this Directive became effective on 9 August 2001.
James Coyne
Delegate of the Civil Aviation Safety Authority 4 March 2004
The above AD is notified in the Commonwealth of Australia Gazette on 24 March 2004.
Overview
The Civil Aviation Safety Authority (CASA) introduced the Airworthiness Directive (AD) AD/B747/251 Amdt 1 in 2004 to address safety concerns related to the fuel quantity indication system (FQIS) wiring of Boeing 747 series aeroplanes. This AD was issued under subregulation 39.1 (1) of the Civil Aviation Safety Regulations 1998. It was enacted in response to findings that electrical transients in the FQIS system could lead to arcing and potential ignition of fuel tanks, posing significant safety risks. The primary policy objective of this AD is to ensure the safe operation of Boeing 747 aeroplanes by mandating the replacement of FQIS wiring with shielded wiring and ensuring proper separation from other aircraft systems. This amendment provides additional compliance methods, including the installation of Smiths Industries Transient Suppression Units, to accommodate previously modified aeroplanes.
Scope and Application
The Airworthiness Directive (AD) issued under subregulation 39.1 (1) of the Civil Aviation Safety Regulations 1998 pertains to all Model 747-100, -200, -300, -SP, and -SR series aeroplanes. This directive, issued by a delegate of the Civil Aviation Safety Authority (CASA), mandates specific actions to address identified safety concerns regarding the fuel quantity indication system (FQIS) wiring. The directive applies to these aircraft models and requires the replacement of the FQIS wiring outside of the fuel tanks and surge tank with shielded wiring, installed in a manner that separates it from other aeroplane systems wiring. This must be done in accordance with an approved method, either through the installation of Smiths Industries Transient Suppression Units in line with specified Boeing Service Bulletins or FAA Letters, or as otherwise approved by the FAA. This AD is applicable within the jurisdictional scope of the Commonwealth of Australia, with its provisions communicated through the Commonwealth of Australia Gazette. Notably, the compliance deadline for these requirements remains unchanged from the original AD issued on 9 August 2001, mandating action before 31 December 2001. This amendment, effective from 15 April 2004, introduces additional acceptable means of compliance to accommodate previously modified aeroplanes.
Key Provisions
The Airworthiness Directive (AD) AD/B747/251 Amdt 1, issued by the Civil Aviation Safety Authority (CASA) delegate, applies to all Model 747-100, -200, -300, -SP, and -SR series aeroplanes. The directive mandates the replacement of all fuel quantity indication system (FQIS) wiring outside of the fuel tanks and surge tank with shielded wiring. This new wiring must be installed in such a way that it is separated from other aeroplane systems wiring, in accordance with a method approved by the Manager, Seattle Aircraft Certification Office, Federal Aviation Administration (FAA), Transport Airplane Directorate. Additionally, installations of Smiths Industries Transient Suppression Units in accordance with Boeing Service Bulletin 747-28-2233 dated 22 February 2001 (FAA STC ST00181SE) or in accordance with methods approved in FAA Letters 130S-00-0391 or 130S-03-375, are considered acceptable means of compliance with this directive. The directive was originally issued on 9 August 2001 and was amended on 4 March 2004 to include an additional alternate method of compliance, allowing the use of alternate indicators in previously modified aeroplanes.
The obligations imposed on the parties governed by this AD include ensuring that the specified modifications to the FQIS wiring are made in accordance with the instructions provided by the FAA. Specifically, operators of the affected Boeing 747 series aeroplanes must replace the fuel quantity indication system wiring with shielded wiring that is separated from other aeroplane systems wiring, and they must do so in a manner approved by the FAA. This directive aims to address a safety concern related to the potential for electrical transients to cause arcing in the fuel system, which could result in ignition of the fuel tank(s). Compliance with this AD is mandatory and must be achieved before 31 December 2001. The AD was effective as of 15 April 2004.
Failure to comply with the requirements of this AD can result in serious safety hazards, as the directive was issued to correct an unsafe condition identified in the fuel quantity indication system wiring. The potential consequences of non-compliance include the risk of electrical transients causing arcing in the fuel system, which could lead to ignition of the fuel tank(s) and subsequent catastrophic failure of the aircraft. The AD does not specify particular offences or penalties, but non-compliance with CASA directives can lead to enforcement actions, including fines, suspension of airworthiness certificates, or other regulatory penalties as deemed appropriate by CASA. The maximum penalties for non-compliance with CASA regulations can include substantial financial penalties and potential criminal charges if the non-compliance results in a serious aviation accident or incident.