AD 98-14-51

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) T98-14-51 that was sent previously to all known U.S. owners and operators of CFM International CFM56-7B series turbofan engines by individual telegrams. This AD requires checks of the Accessory Gearbox (AGB)/Transfer Gearbox (TGB) Magnetic Chip Detector (MCD) for abnormal magnetic particles that indicate a pending starter gearshaft failure, and, removal from service of suspect starter gearshafts and replacement with serviceable parts. This amendment is prompted by reports of 2 inflight engine shutdowns due to uncontained failures of the AGB starter gearshafts. The actions specified by this AD are intended to prevent a dual inflight engine shutdown event, which could result in a forced landing and loss of the aircraft.

Final rule, request for comments

98-14-51 CFM INTERNATIONAL: Amendment 39-10758. Docket 98-ANE-50-AD.
Applicability: CFM International (CFMI) CFM56-7B series turbofan engines, identified by engine serial number (ESN) in CFMI CFM56-7B Service Bulletin (SB) No. 72-130, dated June 29, 1998. These engines are installed on but not limited to Boeing 737-600, 737-700, and 737-800 series aircraft.
Note 1: This airworthiness directive (AD) applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (f) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
Compliance: Required as indicated, unless accomplished previously.
To prevent a possible dual inflight engine shutdown event, which could result in a forced landing and loss of the aircraft, accomplish the following:
(a) Prior to further flight, check the accessory gearbox (AGB)/ transfer gearbox (TGB) magnetic chip detector (MCD) on the No. 2 engine of the aircraft for abnormal magnetic particles that indicate a pending starter gearshaft failure, in accordance with CFMI CFM56-7B SB No. 72-132, dated July 2, 1998, as follows:
(1) If magnetic particles are found to be abnormal in accordance with CFMI CFM56-7B SB No. 72-132, dated July 2, 1998, prior to further flight, remove from service starter gearshafts, part number (P/N) 340-055-202-0, and replace with a serviceable part not identified by S/N in Table 1 of CFMI CFM56-7B SB No. 72-130, dated June29, 1998.
(2) On the next calendar day after checking the No. 2 engine of the aircraft, perform an AGB/TGB MCD check of the No. 1 engine of the aircraft, and, if necessary, remove from service starter gearshafts and replace with serviceable parts in accordance with paragraph (a)(1) of this AD.
(3) Thereafter, perform AGB/TGB MCD checks alternately, every other calendar day, between the No. 2 and No. 1 engines of the aircraft, and, if necessary, remove from service starter gearshafts and replace with serviceable parts in accordance with paragraph (a)(1) of this AD.
(b) Within 350 hours time in service (TIS) after the effective date of this AD, or by August 1, 1998, whichever occurs first, on aircraft with two affected engines installed identified by ESN in Table 1 of CFMI CFM56-7B SB No. 72-130, dated June 29, 1998, remove from service suspect starter gearshafts on the No. 2 engine and replace with a serviceable part not identified by S/N in Table 1 of that SB.
(c) Within725 hours TIS after the effective date of this AD, or by September 1, 1998, whichever occurs first, on aircraft with only one affected engine identified by ESN in Table 1 of CFMI CFM56-7B SB No. 72-130, dated June 29, 1998, remove from service suspect starter gearshafts and replace with a serviceable part not identified by S/N in Table 1 of that SB.
(d) Installation of serviceable starter gearshafts not identified by S/N in Table 1 of CFMI CFM56-7B SB No. 72-130, dated June 29, 1998, constitutes terminating action to the repetitive AGB/TGB MCD checks required by paragraph (a) of this AD.
(e) Report to the Manager of the Engine Certification Office of the FAA within 5 working days of replacement of the starter gearshaft if the ESN listed in Table 1 of CFMI CFM56-7B SB No. 72-130, dated June 29, 1998, does not directly correspond to the adjoining starter gearshaft serial number to verify that all affected parts have been removed from service. The address is: Manager, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; fax (781) 238-7199. Reporting requirements have been approved by the Office of Management and Budget and assigned OMB control number 2120-0056.
(f) 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, Engine Certification Office. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office.

Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.
(g) The actions required by this AD shall be accomplished in accordance with the following CFMI SBs:

Document No.
Pages
Date
CFM56-7B SB No. 72-130
1-33
June29, 1998.
Total pages: 33

CFM56-7B SB No. 72-132
1-12
July 2, 1998
Total pages: 12

This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from CFM International, Technical Publications Department, 1 Neumann Way, Cincinnati, OH 45215; telephone (513) 552-2981, fax (513) 552-2816. Copies may be inspected at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
(h) This amendment becomes effective October 1, 1998, to all persons except those persons to whom it was made immediately effective by telegraphic AD T98-14-51, issued July 2, 1998, which contained the requirements of this amendment.

On July 2, 1998, the Federal Aviation Administration (FAA) issued telegraphic airworthiness directive (AD) T98-14-51, applicable to CFM International (CFMI) CFM56-7B series turbofan engines, which requires checks of the Accessory Gearbox (AGB)/Transfer Gearbox (TGB) Magnetic Chip Detector (MCD) for abnormal magnetic particles that indicate a pending starter gearshaft failure, and, removal from service of suspect starter gearshafts and replacement with serviceable parts. That action was prompted by reports of 2 inflight engine shutdowns on CFM56-7B series turbofan engines installed on Boeing 737-700 series aircraft. The cause of the inflight engine shutdowns were due to uncontained failures of the AGB starter gearshafts. The investigation revealed that the gearshafts failed due to inadequate fatigue capability caused by high residual tensile stresses introduced during the manufacturing process, coupled with the elimination of shotpeening in the gearshaft hub. The manufacturing process has since been modified. The starter gearshaft, part number (P/N) 340-055-202-0, involved in the events are part of a lot of 237 parts manufactured. All of the production engines currently in revenue service or as spares incorporate these suspect starter gearshafts. The engines have been identified by engine serial number (ESN) in Table 1 of CFMI CFM56-7B Service Bulletin (SB) No. 72-130, dated June 29, 1998, and the suspect starter gearshafts have also been identified by serial number (S/N) in that table. Currently, all revenue service Boeing 737-700 and 737-800 series aircraft have the suspect starter gearshafts installed in both engines; therefore, this condition, if not corrected, could result in a dual inflight engine shutdown event, which could result in a forced landing and loss of the aircraft.
The FAA has reviewed and approved the technical contents of CFMI CFM56-7B SB No. 72-130, dated June 29, 1998, that describes procedures for removalfrom service of suspect starter gearshafts and replacement with serviceable parts; and CFMI CFM56-7B SB No. 72-132, dated July 2, 1998, that describes procedures for checks of the AGB/ TGB MCD for abnormal magnetic particles that indicate a pending starter gearshaft failure.
Since the unsafe condition described is likely to exist or develop on other engines of the same type design, the FAA issued Telegraphic AD T98-14-51 to prevent a dual inflight engine shutdown event. The AD requires, prior to further flight, a check of the AGB/TGB MCD on the No. 2 engine of the aircraft for abnormal magnetic particles that indicate a pending starter gearshaft failure. If abnormal magnetic particles are discovered, this AD requires, prior to further flight, removal from service of the starter gearshaft and replacement with a serviceable part not identified by S/N in Table 1 of CFMI CFM56-7B SB No. 72-130, dated June 29, 1998. The required actions are required for the No. 2 engine first becausethe AGB is located on the inboard side of the No. 2 engine. An uncontained starter gearshaft failure on the No. 2 engine would expose the aircraft to a higher risk of damage than an uncontained starter gearshaft failure on the No. 1 engine. This AD also requires, on the next calendar day after checking the No. 2 engine of the aircraft, an AGB/TGB MCD check of the No. 1 engine of the aircraft, and, if necessary, removal from service of starter gearshafts. Thereafter, the AGB/TGB MCD checks must be alternated, every other calendar day, between the No. 2 and No. 1 engines of the aircraft.
This AD also requires, within 350 hours time in service (TIS) after the effective date of this AD, or by August 1, 1998, whichever occurs first, on aircraft with two affected engines installed identified by ESN in Table 1 of CFMI CFM56-7B SB No. 72-130, dated June 29, 1998, on the No. 2 engine of that aircraft, removal from service of suspect starter gearshafts and replacement with a serviceable part not identified by S/N in Table 1 of that SB. On aircraft with only one affected engine identified by ESN in Table 1 of that SB, this AD requires removal from service of suspect starter gearshafts and replacement with a serviceable part not identified by S/N in Table 1 of that SB within 725 hours TIS after the effective date of this AD, or by September 1, 1998, whichever occurs first. Installation of replacement serviceable starter gearshafts constitutes terminating action to the repetitive AGB/TGB MCD checks. The calendar end-dates were determined based upon risk analysis and parts availability.
Finally, this AD requires reporting to the Engine Certification Office of the FAA within 5 working days of replacement of the starter gearshaft; if the ESN listed in Table 1 of CFMI CFM56-7B SB No. 72-130, dated June 29, 1998, does not directly correspond to the adjoining starter gearshaft serial number, in order to verify that all affected parts have been removed from service. The actions are required to be accomplished in accordance with the Accomplishment Instructions in the SBs described previously.
Since it was found that immediate corrective action was required, notice and opportunity for prior public comment thereon were impracticable and contrary to the public interest, and good cause existed to make the AD effective immediately by individual telegrams issued on July 2, 1998, to all known U.S. owners and operators of CFMI CFM56-7B series turbofan engines. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to Section 39.13 of part 39 of the Federal Aviation Regulations (14 CFR part 39) to make it effective to all persons.
Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on thisrule 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 under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.
Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with the substance of this ADwill 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 98-ANE-50-AD." The postcard will be date stamped and returned to the commenter.
The regulations adopted herein will 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 final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES." List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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. 106(g), 40113, 44701. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: