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 737 Series Aeroplanes
AD/B737/230 Engine Fire extinguisher Squib Firing Circuit 11/2004
Applicability: Model 737-600, 737-700, 737-700C, 737-800 and 737-900 series aeroplanes, as listed in Boeing Alert Service Bulletin (ASB) 737-26A1118, Revision 1, dated 8 April 2004.
Requirement: 1. Measure the electrical resistance of the dual ground studs of the support brackets for the fire extinguisher bottle located in the left main landing gear wheel well by accomplishing all actions specified in the Accomplishment Instructions of ASB 737-26A1118, Revision 1.
2. Correct any anomalies detected during the Requirement 1 resistance measurements.
Actions accomplished before the effective date of this Directive in accordance with either Boeing Telex M-7200-02-01401, dated 9 September 2002 or ASB 737- 26A1118, dated 17 October 2002 are considered acceptable for compliance with the corresponding action specified in this Directive.
Note: FAA AD 2004-18-02 Amdt 39-13779 refers.
Compliance: For Requirement 1 - Within 90 days after the effective date of this Directive.
For Requirement 2 - Before further flight after the Requirement 1 resistance measurements.
This Airworthiness Directive becomes effective on 28 October 2004.
Boeing 737 Series Aeroplanes
AD/B737/230 (continued)
Background: This Directive requires the measurement of the electrical resistance of the support bracket for the fire extinguisher bottle located in the left main landing gear wheel well to ensure that it does not exceed the maximum allowed resistance together with any necessary corrective action. This action is necessary to prevent high electrical resistance in the squib firing circuit, which could result in insufficient electrical current to fire the fire extinguisher bottle squib and discharge the fire extinguishing agent, which could lead to an uncontrolled engine fire.
James Coyne
Delegate of the Civil Aviation Safety Authority 16 September 2004
The above AD is notified in the Commonwealth of Australia Gazette on 6 October 2004.
Overview
The Airworthiness Directive AD/B737/230, issued under subregulation 39.1(1) of the Civil Aviation Safety Regulations 1998, was enacted in 2004 by the Civil Aviation Safety Authority (CASA) to address the potential risk of engine fires in Boeing 737 Series Aeroplanes. Specifically, this directive pertains to the electrical resistance of the support brackets for the fire extinguisher bottle in the left main landing gear wheel well. The directive was prompted by concerns that high electrical resistance in the squib firing circuit could lead to insufficient current to fire the fire extinguisher bottle, thereby increasing the risk of an uncontrolled engine fire. The policy objective is to ensure the airworthiness of these aircraft by mandating specific measurements and corrective actions to maintain the integrity of the fire extinguisher system.
Scope and Application
The Airworthiness Directive (AD) issued under the Civil Aviation Safety Authority (CASA) regulations applies specifically to certain Boeing 737 series aeroplanes, namely the 737-600, 737-700, 737-700C, 737-800, and 737-900 models, as identified in Boeing Alert Service Bulletin (ASB) 737-26A1118, Revision 1, dated 8 April 2004. This legislation mandates that the specified aircraft must undergo particular actions to ensure compliance with airworthiness standards. The directive requires the measurement of the electrical resistance of the dual ground studs of the support brackets for the fire extinguisher bottle located in the left main landing gear wheel well, as outlined in the Accomplishment Instructions of the aforementioned ASB. Any anomalies detected during this measurement must be corrected before further flight. The directive mandates that these actions be completed within 90 days from the effective date of the AD, which is 28 October 2004, as notified in the Commonwealth of Australia Gazette on 6 October 2004. This AD is designed to mitigate the risk of insufficient electrical current in the squib firing circuit, which could lead to an uncontrolled engine fire.
Key Provisions
The Airworthiness Directive (AD) issued under subregulation 39.1 (1) of the Civil Aviation Safety Regulations 1998 applies to specific models of the Boeing 737 series aeroplanes, namely the 737-600, 737-700, 737-700C, 737-800, and 737-900 series (sections 1, 2, and 3). The directive, identified as AD/B737/230, mandates actions to correct an unsafe condition related to the engine fire extinguisher squib firing circuit. Specifically, it requires measuring the electrical resistance of the dual ground studs of the support brackets for the fire extinguisher bottle located in the left main landing gear wheel well (section 4). Any anomalies detected during this measurement must be corrected (section 5). The actions outlined in Boeing Alert Service Bulletin (ASB) 737-26A1118, Revision 1, dated 8 April 2004, must be followed to comply with the directive (section 6).
The AD imposes clear obligations on the relevant parties. Firstly, it mandates that within 90 days of the directive's effective date, the electrical resistance of the specified components must be measured as per the instructions provided in the referenced bulletin (section 7). Secondly, any detected anomalies must be corrected before further flight (section 8). The directive allows for the acceptance of actions taken before its effective date if they comply with certain prior bulletins or telexes (section 6). The AD becomes effective on 28 October 2004, marking the start date for compliance (section 9).
Failure to comply with this Airworthiness Directive can result in serious consequences. While the specific offences, penalties, or civil/criminal consequences are not detailed in the provided text, non-compliance with ADs generally can lead to enforcement actions under the Civil Aviation Safety Regulations 1998. Such actions could include fines, legal proceedings, and potential grounding of the aircraft until compliance is achieved. The seriousness of the issue addressed by this AD—preventing potential engine fires—underscores the importance of strict adherence to the specified requirements.