COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Boeing 737 Series Aeroplanes
AD/B737/19 Engine Overheat, Fire Detection and
Fire Extinguishing Systems
Applicability: All 737-200, -300 and -400 aeroplanes.
Requirement: “FIRE EXTINGUISHER BOTTLE CROSS-CONNECTION”
- The routing of the electrical wiring to the fire extinguisher bottles is to be
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permanently modified in such a manner that inadvertent cross-connection of any explosive squib electrical connectors is impossible.
Note: Boeing Service Letter 737-SL-24-57 refers.
ENGINE OVERHEAT, FIRE DETECTION AND FIRE EXTINGUISHING SYSTEMS
2. 737-200 series aircraft. Carry out a functional check of each system in accordance with Boeing Telex M-7272-89-0532 dated 31 January 1989.
3. 737-300 and -400 series aircraft. Carry out a functional check of each system in accordance with Boeing Telex M-7272-89-0530 dated 31 January 1989.
Note 1: Operators of models 737-300 and -400 series aircraft that have completed a functional check of one engine’s overheat and fire detection system, and a continuity check of the second engine’s overheat and fire protection system to comply with FAA AD 89-01-51 dated 11 January 1989, are only required to complete the functional check on the second engine, and the “Fire Extinguishing Wire” portion of the functional test procedure detailed in Boeing Telex M-7272-89-0530 (Requirement 3 above).
Note 2: Boeing have superseded Telex 0156 with 0530.
Note 3: FAA Telegraphic AD T89-03-51 refers to Requirements 2 and 3.
Compliance: Requirement 1: Within 25 days from 7 February 1989.
2 and 3: Within 25 days from 7 February 1989, and thereafter before next flight following any maintenance action involving engine overheat, fire detection and/or fire extinguishing systems which could possibly result in cross-connection or mis- connection of any system wiring or plumbing.
Background: Requirement 1: Boeing have advised that the possibility exists that the electrical connectors for the fire bottle explosive squibs can be cross-connected. Under some circumstances this could result in the fire extinguisher bottle being dispensed to both engines simultaneously. Note that unlike, Boeing Service Letter 737-SL-24-57, applicability is not limited to a specific line position number.
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Requirements 2 and 3: There have been reports in the last several months of improperly installed wiring and/or plumbing in the engine and cargo compartment Fire Protection System on various model Boeing aircraft. Whilst the cause of these problems has not been identified in each case, the FAA has determined that, due to design similarity or common production lines, these conditions are likely to exist on other fire protection systems of other Boeing aircraft not covered by previous AD action, and that as a precautionary measure, checks must be performed on specified aircraft.
Overview
The Civil Aviation Regulations 1998, as amended, form the foundation of Australian civil aviation safety law, and Part 39 - 105, which includes the Schedule of Airworthiness Directives, is particularly significant in ensuring the safety of aeroplanes in service. This legislative instrument, enacted by the Commonwealth of Australia, aims to address specific safety concerns identified in Boeing 737 Series aeroplanes, particularly focusing on engine overheat, fire detection, and fire extinguishing systems. The directive mandates modifications and checks to prevent the risk of electrical cross-connections that could lead to the simultaneous dispensing of fire extinguisher bottles, a situation that could exacerbate engine fires. Compliance with these directives is essential to mitigate potential hazards and maintain the airworthiness of the specified aircraft models.
Scope and Application
The Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives under the Civil Aviation Regulations 1998 applies specifically to Boeing 737 Series Aeroplanes, including the 737-200, -300, and -400 models. This legislation mandates modifications to the electrical wiring of the fire extinguisher bottles to prevent inadvertent cross-connection, which could lead to simultaneous dispensing of fire extinguishers to both engines. The requirements are stringent, demanding that the wiring modifications be completed within 25 days from 7 February 1989. Additionally, functional checks of the engine overheat, fire detection, and fire extinguishing systems are mandated for the specified 737 models, with checks to be performed within 25 days from the same date and before the next flight following any maintenance action involving these systems. This directive ensures safety by addressing identified risks of wiring misconnections, which could compromise the effectiveness of fire suppression systems on board these aircraft.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, includes an Airworthiness Directive (AD) for Boeing 737 Series Aeroplanes, focusing on engine overheat, fire detection, and fire extinguishing systems. Section AD/B737/19 mandates modifications to the routing of electrical wiring to fire extinguisher bottles to prevent inadvertent cross-connection of explosive squib electrical connectors. This applies to all 737-200, -300, and -400 aeroplanes and is to be completed within 25 days from 7 February 1989. Additionally, operators must carry out functional checks of the systems in accordance with specific Boeing Telex communications: Telex M-7272-89-0532 for 737-200 series aircraft and Telex M-7272-89-0530 for 737-300 and -400 series aircraft.
The AD imposes obligations on aircraft operators to ensure the specified modifications are completed and functional checks are conducted. For 737-300 and -400 series aircraft, if a functional check has already been completed on one engine's system, and a continuity check has been done on the second engine's system, operators are only required to complete the functional check on the second engine and the "Fire Extinguishing Wire" portion of the test. These checks must be carried out within 25 days from 7 February 1989 and before the next flight following any maintenance action that could result in cross-connection or misconnection of system wiring or plumbing.
Failure to comply with the requirements of AD/B737/19 may result in serious safety issues, including the risk of simultaneous dispensing of fire extinguisher bottles to both engines, which could lead to catastrophic consequences. Although specific penalties are not outlined in the AD, non-compliance with Civil Aviation Regulations could lead to enforcement actions by the Civil Aviation Safety Authority, including fines, suspension of airworthiness certificates, or other regulatory actions. These consequences underscore the importance of adhering to the AD to ensure the safety and airworthiness of Boeing 737 Series Aeroplanes.