Airworthiness Directives; CFM International CFM56-7B Series Turbofan Engines

[Federal Register Volume 63, Number 179 (Wednesday, September 16, 1998)]
[Rules and Regulations]
[Pages 49423-49425]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-24644]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-50-AD; Amendment 39-10758; AD 98-14-51]
RIN 2120-AA64


Airworthiness Directives; CFM International CFM56-7B Series 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule, request for comments.

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SUMMARY: 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.

DATES: 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.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of October 1, 1998.
    Comments for inclusion in the Rules Docket must be received on or 
before November 16, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 98-ANE-50-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may also be sent 
via the Internet using the following address: ``9-ad-
[email protected]''. Comments sent via the Internet must contain 
the docket number in the subject line.
    The applicable service information may be obtained from CFM 
International, Technical Publications Department, 1 Neumann Way, 
Cincinnati, OH 45215; telephone (513) 552-2981, fax (513) 552-2816. 
This information may be examined 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; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., Suite 700, Washington, DC 
20001.

FOR FURTHER INFORMATION CONTACT: Glorianne Messemer, Aerospace 
Engineer, Engine Certification Office, FAA, Engine and Propeller 
Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; 
telephone (781) 238-7132, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: 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

[[Page 49424]]

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 removal from 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 because the 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 
Sec. 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 this 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 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 
AD 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 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

[[Page 49425]]

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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

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 
June 29, 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) Within 725 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  June 29, 1998.             
Total pages: 33.                                                        
CFM56-7B SB No. 72-132.............    1-12  July 2, 1998.              
Total pages: 12.                                                        
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    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.

    Issued in Burlington, Massachusetts, on September 8, 1998.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 98-24644 Filed 9-15-98; 8:45 am]
BILLING CODE 4910-13-U

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