# Airworthiness Directives; Teledyne Continental Motors (formerly Bendix) S-20, S-1200, D-2000, and D-3000 Series Magnetos > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/fr%3A94-28375 ## Record - **Collection:** Federal Register - **Document type:** Uncategorized Document - **Published:** November 17, 1994 ## Text SUMMARY: This notice revises an earlier proposed airworthiness directive (AD), applicable to Teledyne Continental Motors (TCM) (formerly Bendix) S-20, S-1200, D-2000, and D-3000 series magnetos equipped with impulse couplings, that would have superseded an AD that currently requires inspections for wear, and replacement, if necessary, of the impulse coupling assemblies. The proposed rule would have retained the repetitive inspections for wear required by the current AD, but would have also required replacement, if necessary, of riveted impulse coupling assemblies with newly designed, improved, snap ring impulse coupling assemblies. In addition, the proposed AD would have required marking the magneto data plate to indicate installation of a snap ring impulse coupling assembly. Installation of snap ring impulse coupling assemblies would have constituted terminating action to the inspection requirements of the AD. That proposal was prompted by availability of an improved design for the impulse coupling assembly. This action revises the proposed rule by retaining the 500 hour repetitive inspections for wear required by the current AD but makes them effective for the snap ring couplings as well. The actions specified by this proposed AD are intended to prevent magneto failure and subsequent engine failure. DATES: Comments must be received by January 17, 1995. ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Assistant Chief Counsel, Attention: Rules Docket No. 93-ANE-07, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may be inspected at this location between 8:00 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. The service information referenced in the proposed rule may be obtained from Teledyne Continental Motors, P.O. Box 90, Mobile, AL 36601; telephone (205) 438-3411. This information may be examined at the FAA, New England Region, Office of the Assistant Chief Counsel, 12 New England Executive Park, Burlington, MA. FOR FURTHER INFORMATION CONTACT: Jerry Robinette, Aerospace Engineer, Atlanta Aircraft Certification Office, FAA, Small Airplane Directorate, 1669 Phoenix Parkway, Suite 210C, Atlanta, GA 30349; telephone (404) 991-3810, fax (404) 991-3606. SUPPLEMENTARY INFORMATION: Comments Invited Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received. Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket. Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 93-ANE-07.'' The postcard will be date stamped and returned to the commenter. Availability of NPRMs Any person may obtain a copy of this NPRM by submitting a request to the FAA, New England Region, Office of the Assistant Chief Counsel, Attention: Rules Docket No. 93-ANE-07, 12 New England Executive Park, Burlington, MA 01803-5299. Discussion On January 4, 1983, the Federal Aviation Administration (FAA) issued airworthiness directive (AD) 78-09-07 R3, Amendment 39-4538 (48 FR 1482, January 13, 1983), to require inspections for wear, and replacement, if necessary, of the impulse coupling assemblies on certain Teledyne Continental Motors (TCM) (formerly Bendix) S-20, S- 1200, D-2000, and D-3000 series magnetos equipped with impulse couplings. That action was prompted by reports of numerous magneto failures. That condition, if not corrected, could result in magneto failure and subsequent engine failure. A proposal to amend part 39 of the Federal Aviation Regulations was published as a notice of proposed rulemaking (NPRM) in the Federal Register on September 21, 1993 (58 FR 48987). That NPRM would have retained the repetitive inspections for wear required by the current AD, but would have also required replacement, if necessary, of the riveted impulse coupling assembly with newly designed, improved, snap ring impulse coupling assemblies. In addition, the proposed AD would have required marking the magneto data plate to indicate installation of a snap ring impulse coupling assembly. Installation of snap ring impulse coupling assemblies would have constituted terminating action to the inspection requirements of this AD. That NPRM was prompted by the manufacturer redesigning the impulse coupling assembly to include snap ring fastening technology which strengthens the cam axle and reduces wear. The snap ring impulse coupling assembly was believed not to have the failure mode of the previous design. Since the issuance of that NPRM, the FAA has received reports of snap ring impulse coupling assemblies being worn beyond limits. This supplemental proposed AD would therefore retain the 500 hour repetitive inspections for wear required by the current AD, but would require these inspections for magnetos equipped with snap ring impulse coupling assemblies as well. Since this change expands the scope of the originally proposed rule, the FAA has determined that it is necessary to reopen the comment period to provide additional opportunity for public comment. The FAA has reviewed and approved the technical contents of TCM Mandatory Service Bulletin (MSB) No. MSB645, dated April 4, 1994, that describes procedures for inspection of the impulse coupling assemblies for wear; and TCM SB No. 639, dated March 1993, that clarifies procedures for installation of impulse coupling assemblies. The FAA estimates that 130,000 magnetos would be affected by this proposed AD, that the required inspection would take 1 work hour, plus 1 work hour to change the impulse coupling, and that the average labor rate is $55 per work hour. The average utilization of the fleet of these airplanes is estimated to be evenly divided between commercial/ commuter service and private owners. The commercial/commuter service population is estimated to operate 500 hours time in service (TIS) per year; therefore the cost to perform the inspections required by the proposed AD would be approximately $3,575,000 per year. The FAA estimates that private owners operate their aircraft between 50 and 100 hours TIS per year; therefore it will take approximately 5 to 10 years to reach 500 hours time in service. The estimated cost for these owners would also be $3,575,000 spread over a time period of 5 to 10 years or 715,000 per year for 5 years or $357,500 for 10 years. The cost to replace the impulse coupling assembly is $125 per magneto plus one work hour at $55 per work hour for a total of $180 per magneto. While all the riveted impulse coupling assemblies will eventually have to be replaced, it is not possible to estimate the cost per year. The total cost for replacement for U.S. operators would be $23,400,000. The regulations proposed herein would not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with Executive Order 12612, it is determined that this proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. For the reasons discussed above, I certify that this proposed regulation (1) is not a ``significant regulatory action'' under Executive Order 12866; (2) is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES. List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Safety. The Proposed Amendment Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: PART 39--AIRWORTHINESS DIRECTIVES 1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89. Sec. 39.13 [Amended] 2. Section 39.13 is amended by adding the following new airworthiness directive: Teledyne Continental Motors: Docket No. 93-ANE-07. Applicability: Teledyne Continental Motors (TCM) (formerly Bendix) S-20, S-1200, D-2000, and D-3000 series magnetos equipped with impulse couplings, installed on but not limited to reciprocating engine powered aircraft manufactured by Beech, Cessna, Mooney, and Piper. Note: The Federal Aviation Administration (FAA) has received reports of some confusion as to what is meant by S-20, S-1200, D- 2000, and D-3000 series magnetos as referenced in TCM Mandatory Service Bulletin (MSB) No. MSB645, dated April 4, 1994, and this airworthiness directive (AD). A typical example is S6RN-25, where the S designates single type ignition unit (a D designates a dual ignition unit), the 6 designates the number of cylinders, the R designates right hand rotation, the N is the manufacturer designation (this did not change when TCM purchased the Bendix magneto product line), and the number after the dash indicates the series (a-25 is a S-20 series magneto while a-3200 is a D-3000 series magneto, etc.). Compliance: Required as indicated, unless accomplished previously. To prevent magneto failure and subsequent engine failure, accomplish the following: (a) For magnetos with riveted or snap ring impulse coupling assemblies, having less than 450 hours time in service (TIS) since new, or overhaul, or since last inspection, on the effective date of this AD, accomplish the following: (1) Prior to the accumulation of 500 hours TIS since new, or overhaul, or since last inspection, inspect riveted or snap ring impulse coupling assemblies for wear, and replace, if necessary, prior to further flight, with serviceable snap ring impulse coupling assemblies, in accordance with the Detailed Instructions of TCM MSB No. MSB645, dated April 4, 1994, and TCM SB No. 639, dated March 1993. (2) Thereafter, at intervals not to exceed 500 hours TIS since the last inspection, inspect riveted or snap ring impulse coupling assemblies for wear, and replace, if necessary, prior to further flight, with serviceable snap ring impulse coupling assemblies, in accordance with the Detailed Instructions of TCM MSB No. MSB645, dated April 4, 1994, and TCM SB No. 639, dated March 1993. (b) For magnetos with riveted or snap ring impulse coupling assemblies, having 450 or more hours TIS since new, or overhaul, or since last inspection, on the effective date of this AD, or an unknown TIS on the effective date of this AD, accomplish the following: (1) Within the next 50 hours TIS after the effective date of this AD, inspect riveted or snap ring impulse coupling assemblies for wear, and replace, if necessary, prior to further flight, with serviceable snap ring impulse coupling assemblies in accordance with the Detailed Instructions of TCM MSB No. MSB645, dated April 4, 1994, and TCM SB No. 639, dated March 1993. (2) Thereafter, at intervals not to exceed 500 hours TIS since the last inspection, inspect riveted or snap ring impulse coupling assemblies for wear, and replace, if necessary, prior to further flight, with serviceable snap ring impulse coupling assemblies, in accordance with the Detailed Instruction of TCM MSB No. MSB645, dated April 4, 1994, and TCM SB No. 639, dated March 1993. (c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Atlanta Aircraft Certification Office. The request should be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Atlanta Aircraft Certification Office. Note: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Atlanta Aircraft Certification Office. (d) Special flight permits may be issued in accordance with Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the aircraft to a location where the requirements of this AD can be accomplished. Issued in Burlington, Massachusetts, on November 9, 1994. James C. Jones, Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service. [FR Doc. 94-28375 Filed 11-16-94; 8:45 am] BILLING CODE 4910-13-P --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A94-28375. Public record. Not legal advice.