COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Electrical Equipment
AD/ELECT/42
Amdt 1
Bendix Impulse Couplings 1/86
Applicability: All Bendix Magnetos with type designations as follows:
S4LN-21/1225/1227, S4RN-21/1225/1227, S6LN-21/23/25/1225/1227, S6RN- 21/23/25/1225/1227, S4LN-200 P/N 10-163005-7 D-2021/2031. All D-3000 except
Bendix Blue Label Impulse Coupled Magnetos Serial Number 8236001 and above and except Bendix Red Label Impulse Coupled Magnetos with the following Serial Numbers and above:
S-20 Series B-001171 or A297043. S-200 Series B-001732 or A297043.
S-1200 Series B-001162 or A297043. D-2000 Series 35550.
D-3000 Series B-000249 or 5806.
Requirement: Bendix Service Bulletin No. 623 A and FAA AD 82-20-0 refer. For all affected impulse couplings having less than 300 operating hours -
- Remove magneto from the engine in accordance with engine/aircraft manufacturers published instructions.
2. Place the magneto in a suitable work stand with the impulse coupling facing up.
3. Use finger pressure to push inward on the toe of each flyweight so that the flyweight heel protrudes outward.
4. Using a fine number 1 double cut 1/2 inch wide file at least 3/32 inch thick pass the file across the heel of the flyweight attempting to remove material. If the flyweight has been properly heat treated the file will glide smoothly over the heel of the flyweight removing no material. If the flyweight is not properly heat treated (soft) the file will not glide easily across the surface of the flyweight heel and material will be removed.
5. If an improperly heat treated (soft) flyweight is found, immediately remove and replace the cam assembly and/or the impulse coupling assembly with an assembly meeting the requirement of this AD, following procedures in the Magneto Overhaul Instructions and paying strict attention to Notes and Cautions.
6. Inspect the impulse coupling stop pins for wear and replace as necessary.
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
7. After flyweights have been identified, stop pins inspected, and the impulse coupling reinstalled on the magneto; if removed; identify the magneto by stamping a 1/16 inch letter F in the upper right corner of the identification plate to indicate that this AD and Bendix Service Bulletin No. 623A have been complied with.
8. Reinstall the magneto following manufacturer's published procedures.
9. Make an appropriate engine log book entry recording magneto serial number to indicate that this AD and Bendix Service Bulletin No. 623A have been complied with.
10. Inspect all spare impulse coupling assemblies, cam assemblies and magnetos following the same procedures described in Steps 3 and 4 of this Airworthiness Directive. If both flyweights are found acceptable, identify the cam assembly by applying yellow Dykem or yellow lacquer to the heel of each flyweight. Stamp F on Data plate as described in Step 7.
Note 1. The magneto should be removed from the engine only to the extent necessary to perform the inspection described herein. Depending on the engine application it may not be necessary to remove the harness from the magneto for the inspection procedure.
Note 2. All magnetos with the impulse coupling recessed into the magneto flange must have the impulse coupling removed from the magneto to perform the inspection. This is a bench operation and will require the magneto to be removed from the engine and the harness removed from the magneto.
Note 3. Whenever an impulse coupling is removed from a magneto, it must be removed following manufacturer's published procedures paying strict attention to Notes and Conditions. Follow manufacturers published procedures, cautions and torque settings upon re-assembly. The cotter pin Bendix P/N 10-90751-18 removed during disassembly must be discarded and replaced.
Note 4. FAA Emergency AD82-20-0 specifies the above checks “For impulse couplings having less than 300 operating hours”. Compliance with AD/ELEC/27B should ensure detection of excessive wear in longer time components
Compliance: Within next 100 hours of engine operation after 30 November, 1982.
Background: 1 This Directive is amended to highlight the latest revision to the referenced Service Bulletin. Torque figures and procedures are revised.
2. Engine stoppage, attributed to failure of the magneto impulse coupling, has occurred in two aircraft (less than 200 hours operating time). It was found that the impulse coupling flyweights had been improperly heat treated (soft) and had worn rapidly and jammed. It is believed this damaged the engine accessory drive resulting in engine failure.
Overview
The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority (CASA), encompass various safety directives to ensure airworthiness and safety in aviation. One such directive is AD/ELECT/42 Amendment 1, addressing the issue of improperly heat-treated flyweights in Bendix magnetos. This directive was introduced to mitigate the risk of engine stoppage and potential engine failure due to the jamming of impulse coupling flyweights. The problem it addresses stems from instances where the flyweights in certain Bendix magnetos were not properly heat-treated, leading to rapid wear and subsequent jamming that could cause engine malfunctions. The policy objective is to enhance aviation safety by ensuring that all affected magnetos undergo the necessary inspections and repairs to prevent such failures.
The directive mandates specific procedures for the inspection and potential replacement of impulse coupling components in Bendix magnetos, particularly focusing on flyweights and stop pins. Compliance with the directive is required within 100 hours of engine operation following the specified date. This ensures that all affected aircraft are promptly brought into compliance, thereby reducing the risk of engine stoppage and enhancing overall flight safety. The detailed procedures outlined in the directive ensure that all inspections and repairs are carried out in accordance with the manufacturer's instructions and industry standards.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 107, mandates the application of Airworthiness Directives (AD) to ensure the safety of civil aviation. AD/ELECT/42 Amendment 1 pertains to Bendix Magnetos with specified type designations and serial numbers, necessitating checks and maintenance on their impulse couplings to prevent engine stoppages due to wear and failure. This directive applies to all aircraft operators and maintenance personnel working on aircraft engines equipped with the affected Bendix Magnetos. Geographically, the regulations apply across the Commonwealth of Australia, enforced by the Civil Aviation Safety Authority (CASA). The directive outlines specific inspection and maintenance procedures for magnetos with less than 300 operating hours, requiring the removal of magnetos from the engine for detailed inspection and maintenance of impulse coupling components. Exemptions or exclusions are not explicitly stated within the text, implying that all specified magnetos must comply with the directive. The regulation extends its application through subordinate instruments that detail specific technical procedures and standards, ensuring uniformity in compliance and maintenance practices across the industry.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39, Section 107, mandates that all Bendix Magnetos with specific type designations must adhere to the Airworthiness Directive AD/ELECT/42 Amendment 1. This directive applies to certain Bendix Magnetos, excluding some with specific serial numbers. The primary requirement outlined in the directive involves a thorough inspection and possible modification of the impulse coupling assemblies, particularly for those magnetos with less than 300 operating hours. The directive stipulates that the magneto should be removed from the engine and placed in a suitable work stand, with the impulse coupling facing up. The inspection process involves using a fine file to test the hardness of the flyweight heels; if the file removes material, the flyweight is deemed improperly heat-treated and must be replaced. Additionally, the directive mandates the inspection and replacement of the impulse coupling stop pins as necessary and requires identification markings on the magneto to indicate compliance with the directive and relevant service bulletins. Following the inspection and any necessary repairs, the magneto must be reinstalled according to the manufacturer's instructions, and appropriate records must be made in the engine log book.
The Civil Aviation Safety Authority imposes several obligations on the parties governed by this directive. Operators and maintainers of aircraft equipped with the specified Bendix Magnetos must ensure that the required inspections and modifications are carried out within 100 hours of engine operation after the specified date. This includes following the detailed procedures outlined in the directive, such as the removal of the magneto from the engine, the inspection of the flyweights and stop pins, and the application of identification markings. The directive also requires adherence to the manufacturer's published procedures and cautions when performing these tasks. Operators and maintainers must ensure that all modifications are documented and recorded accurately in the engine log book. Furthermore, any spare impulse coupling assemblies, cam assemblies, and magnetos must also be inspected according to the same procedures.
Failure to comply with the requirements set forth in the Airworthiness Directive AD/ELECT/42 Amendment 1 may result in significant consequences. Although the specific penalties are not detailed in the text, non-compliance with Civil Aviation Regulations can generally lead to enforcement actions by the Civil Aviation Safety Authority. Such actions may include fines, operational restrictions, or other regulatory penalties. Additionally, failure to adhere to airworthiness directives can compromise the safety of the aircraft, potentially leading to engine failure and associated risks. Therefore, it is crucial for operators and maintainers to strictly follow the directive to ensure compliance and maintain the airworthiness of the aircraft.