COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
CFM International Turbine Engines - CFM56 Series
AD/CFM56/11 Accessory and Transfer Gearbox Replacement
6/98 TX
Applicability: CFM International (CFMI) CFM 56-5, 56-5B and 56-5C, all models, turbofan engines with serial numbers as listed below (Warning: some engines may appear in more than one list):
List 1A: (First batch of CFM56-5 Engines with suspect gearshaft cluster spur assembly 31x71 teeth (line 2) in the accessory gearbox (AGB). Engines Serial Number (ESN): 731951, 731954, 731955, 731959, 731960, 731962, 731963,
731966, 731969 (See Service Bulletin CFM56-5 S/B 72-523 Revision 1).
List 1B: (Second batch of CFM56-5 engines with suspect gearshaft cluster spur assembly 31x71 teeth (line 2) in the accessory gearbox (AGB). ESN 731943 to 731948, 731952, 731953, 731956 to 731958, 731973. (See Service Bulletin CFM56-5
S/B 72-523 Revision 1).
List 2A: (First batch of CFM56-5B Engines with suspect gearshaft cluster spur assembly 31x71 teeth (line 2) in the accessory gearbox (AGB). ESN: 779316, 779318, 779322, 779323, 779330, 779332, 779339 (See Service Bulletin CFM56-5B
S/B 72-211 Revision 1).
List 2B: (Second batch of CFM56-5B Engines with suspect gearshaft cluster spur assembly 31x71 teeth (line 2) in the accessory gearbox(AGB). ESN 779307 to 779315, 779317, 779327 (See Service Bulletin CFM56-5B S/B 72-211 Revision 1).
List 3A: (First batch of CFM56-5C engines with suspect gearshaft cluster spur assembly 31x71 teeth (line 2) in the accessory gearbox (AGB) ESN: 741666, 741668, 741670 to 741674, 741676, 741677, 741680, 741682, 741684 (see Service
Bulletin CFM56-5C S/B 72-350 Revision 1).
List 3B: (Second batch of CFM56-5C engines with suspect gearshaft cluster spur assembly 31x71 teeth (line 2) in the accessory gearbox (AGB). ESN: 741653, 741655, 741665, 741667, 741669, 741675, 741678, 741679, 741681 (see Service
Bulletin CFM56-5C S/B 72-350 Revision 1).
Requirement: 1. For all engines in Lists 1A and 1B above, remove from service the gearshaft cluster spur assembly (31x71 teeth) in the AGB in accordance with the instructions of Service Bulletin CFM56-5 S/B 72-523 Revision 1.
2. For all engines in Lists 2A and 2B above, remove from service the gearshaft cluster spur assembly (31x 71 teeth) in the AGB in accordance with the instructions of Service Bulletin CFM56-5B S/B 72-211 Revision 1.
3. For all engines in Lists 3A and 3B above, remove from service the gearshaft cluster spur assembly (31x 71 teeth) in the AGB in accordance with the instructions of Service Bulletin CFM56-5C S/B 72-350 Revision 1.
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
4. For twin engined aircraft, with both engines applicable, all suspect gearshafts on one of the engines must be replaced in accordance with actions 1-2 above.
5. For four engined aircraft which have more than one engine applicable to the provisions of this directive, replace all suspect gearshafts, on all applicable engines (in accordance with actions 2-7 above), such that no more than one applicable engine with suspect gearshafts remains in service on any four engined aircraft.
Note 1: Actions listed above which have already been completed under AD/CFM- 56/8 need not be repeated under this directive.
Note 2: DGAC T98-097 (B) dated 25 February 1998 refers.
Compliance: 1. Before 01 February 1998.
2. Engines on List 2A before 01 February 1998; engines on List 2B before 15 April 1998.
3. Engines on List 3A before 01 February 1998; engines on List 3B before 15 April 1998.
4. Before next flight.
5. Before next flight.
This airworthiness directive becomes effective on 26 March 1998.
Background: Three in flight shut downs were experienced due to failure of starter gearshafts in the accessory gearbox (AGB). The first analysis results shows also a risk of failure of the conical gearshafts of the transfer gearbox (TGB) which could lead to an in flight shut down. This directive supersedes the CFM56-5 requirements of AD/CFM-56/8 which has been cancelled.
Overview
The Civil Aviation Regulations 1998, enacted by the Commonwealth of Australia, address various aspects of civil aviation safety, including the issue of airworthiness directives for specific aircraft components. The problem this legislation aimed to address was the in-flight shut downs caused by failures in the starter gearshafts of the accessory gearbox (AGB) in CFM International CFM56 Series engines. This risk extended to the conical gearshafts of the transfer gearbox (TGB), which could also lead to in-flight shut downs. The objective of the policy was to ensure that these engines are maintained and operated safely by mandating the replacement of specified components. The regulations were enacted to provide a framework for maintaining the airworthiness of aircraft, thereby enhancing safety standards in civil aviation.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 106, under the Civil Aviation Safety Authority, mandates the replacement of certain components in CFM International Turbine Engines - CFM56 Series to ensure airworthiness. This directive applies to CFM56-5, 56-5B and 56-5C turbofan engines with specific serial numbers outlined in three distinct lists, which are identified based on their potential risk due to suspected gearshaft cluster spur assembly issues in the accessory gearbox. The directive is jurisdictional in scope, applying throughout Australia under the Commonwealth's civil aviation regulations. The requirements vary depending on the model of the engine and its serial number, necessitating the removal of specified components in accordance with detailed service bulletins. Compliance with the directive must be achieved before specific dates, and for twin and four-engined aircraft, specific conditions apply regarding the number of engines that must be compliant before the next flight. Notably, actions already completed under previous directives do not need to be repeated. This directive extends its application through the referenced service bulletins and other subordinate instruments, ensuring that all applicable engines are subject to the specified maintenance actions to mitigate the identified safety risks.
Key Provisions
The Civil Aviation Regulations 1998, under PART 39 - 106, outline specific requirements for the maintenance and operation of CFM International Turbine Engines, specifically the CFM56 Series, as detailed in AD/CFM56/11 (6/98 TX). The directive focuses on the removal and replacement of certain gearshaft cluster spur assemblies in the accessory gearbox (AGB) of affected engines. Section 1 of the directive mandates the removal of the 31x71 teeth gearshaft cluster spur assembly from service for specific serial numbers listed in different categories: List 1A and 1B for CFM56-5 engines, List 2A and 2B for CFM56-5B engines, and List 3A and 3B for CFM56-5C engines. Each category of engines must follow specific Service Bulletins for the removal process.
The directive imposes clear obligations on operators and maintenance personnel. Operators must ensure that the specified gearshaft cluster spur assemblies are removed and replaced according to the outlined instructions and timelines. Maintenance personnel must follow the guidance in the relevant Service Bulletins (CFM56-5 S/B 72-523 Revision 1, CFM56-5B S/B 72-211 Revision 1, and CFM56-5C S/B 72-350 Revision 1) to perform the replacements. The directive also specifies that twin-engined aircraft must replace the suspect gearshafts on one engine, while four-engined aircraft must ensure that no more than one engine with suspect gearshafts remains in service at any time.
Failure to comply with the requirements set forth in this directive can lead to serious consequences. The directive highlights the critical nature of the issue by referencing in-flight shutdowns caused by failures in the starter gearshafts of the accessory gearbox (AGB). The regulations do not explicitly state penalties, but non-compliance could potentially lead to safety violations and aircraft being grounded until the necessary repairs are made, which could result in significant operational disruptions and financial losses for the operators.